,,gilbert ,,weather ,,bureau 7,,meteorology7 ,,for ,,boys ,,by ,,alfred ,c4 ,,gilbert ,yale ,university1 #aiji ,published by ,,the ,a4 ,c4 ,,gilbert ,,company ,,new ,,haven1 ,,conn4 ,new ,york ,chicago ,san ,francisco ,toronto ,london ,copyright1 #aibj1 by ,a4 ,c4 ,,gilbert ,new ,haven1 ,conn4 ,,weather ,,indications ,a ,study of the ,weather ,in the minds of most people a very silly notion prevails about the weather and the weather man4 ,they have a general impression that the weather knows no laws--that it is lawless and reckless1 fickle and changeable2 that the weather man is a sort of conjurer1 and by some mysterious gift he is able to prophesy things that most people know nothing about4 ,nothing could be further from the truth4 ,after you have carried out the simple experiments described1 and have read this text1 whether you have a scientific trend of mind or not1 you will at least learn that the weather is a science1 like electricity1 chemistry1 or medicine2 that its laws are uniform1 constant1 and unchanging1 and there is really nothing mysterious about it4 ,the weather man is a scientist and by means of instruments1 which indicate certain things1 he comes to definite conclusions4 ,he is not a prophet2 he does not prophesy2 he forecasts4 ,if you are interested in having a ,weather ,bureau station of your own1 you will find it one of the most interesting things you ever acquired in your life4 ,you will soon gain a knowledge of a subject that most people are quite ignorant of1 and if you desire to stand for leadership among your boy friends1 it may be achieved by knowing about those things that to most boys1 and in fact to adults1 assume a mysterious and magical aspect4 ,a ,weather ,bureau station at your home will give you a source of pleasure1 fun1 and insight into a science that is intensely interesting1 easy to understand1 fascinating and worth while knowing4 ,the importance of the subject cannot be overestimated4 ,it has an influence on the whole world2 it affects our health2 it affects our comfort2 it means success or failure in farming2 it has an immense influence upon transportation4 ,when ready to move perishable goods1 the transporter must have indications of what the weather is going to be4 ,the weather observer is the guardian angel of the ships at sea2 some men have doubts as to whether medicine itself has saved more human lives than the study of the weather and the practice of weather observing4 ,it is not unusual for those who live along the coast to see ships hovering into cover long before a storm approaches1 for the wonderful weather bureau system operated by the ,united ,states ,government gives warnings and danger signals all over the country4 ,statistics show that losses have been reduced seventy-five to eighty per cent through this system4 ,the marine warnings are so perfect1 so prompt1 and so efficient that for a great many years no long or hard storms have ever reached any part of the ,united ,states without advance warnings and danger signals being shown beforehand4 ,when a storm is brewing1 the ,government's wonderful ,weather ,bureau organization watches every atmospheric change with the greatest care and concern1 and takes observations every few hours1 and telegraphs the indications to all places where a warning should be given4 ,thereby perishable goods that need protection can be looked after4 ,when extra hazardous storms and weather changes of a severe character are indicated1 hundreds of thousands of telegrams are sent out in a comparatively short time1 to all parts of the country1 so that interested parties may prepare for such conditions4 ,one can readily see the great service rendered and the satisfaction it must be to the shipper and the farmer to know that his property1 which might be destroyed by a bad storm or low temperature1 is being constantly and carefully guarded against danger4 ,not only storms and great cold waves have been forecasted1 but floods have been anticipated and warnings given4 ,this brings us to a study of the subject 8,weather10 and the best way to learn about the weather is to first learn about the air4 ,,the ,,air ,if you were to ask ninety-nine people out of a hundred to take the stopper out of a bottle1 to look into it1 and to smell its contents1 and then ask them if1 in their opinion1 it contained anything1 the invariable answer would be3 8,it contains nothing40 ,,experiment ,,no4 #a ,take the stopper out of a bottle and endeavor to pour water into it rapidly and see what happens4 7,see ,fig4 #a47 ,one of the laws in ,physics is that no two bodies can occupy the same space at the same time4 ,after doing this experiment1 you will come to the conclusion that the bottle does contain something1 and that 8something0 is matter1 and that matter is air4 ,there is in the bottle probably as important a thing as you could possibly conceive of1 because even this earth without its ocean of air would be a world of desolation2 for air sustains life itself1 and when agitated1 develops great strength4 ,it may be whirled about into a hurricane blast and assume such violent proportions that villages will be swept away1 and great waves of water will be raised1 upon which ships can be tossed about like so much chaff4 ,we all know that air can become so cold that great suffering will be caused1 and so hot that it will make life almost unbearable4 ,we really live in an ocean of air4 ,illustration3 ,fig4 #a ,illustration3 ,fig4 #b ,,the ,,ocean ,,of ,,air ,as the fishes live at the bottom of the ocean of water1 mankind lives at the bottom of an 8ocean of air40 7,see ,fig4 #b47 ,no one is absolutely certain about the depth of this air1 but it has been estimated as low as forty miles and as high as two hundred miles4 ,balloons have gone up to a height of nearly nineteen miles 7#ajj1cbj feet74 ,we do know that the higher we go1 the thinner the air becomes4 ,it is practically impossible for man to ascend into the air more than five or six miles1 owing to the fact that the air above that height is so thin that there is not enough to breathe4 ,naturally1 the air at the bottom is more compact because of the vast amount of air above4 ,the air is a great weight lying upon us--#ad4g pounds per square inch of surface4 ,,how ,,to ,,prove ,,by ,,experiment ,,that ,,air ,,has ,,weight ,the air-globe is a piece of apparatus for demonstrating that air has weight4 7,see ,fig4 #c47 ,first1 the air-globe is weighed and then the air is pumped into it2 its stop-cock is closed and the globe is reweighed4 ,it will be found to have gained in weight4 ,this is conclusive that air is matter and that it has weight4 ,illustration3 ,fig4 #c ,illustration3 ,fig4 #d ,of great importance to us in the study is the next fact1 that air exerts pressure on everything about us and upon ourselves4 ,,experiment ,,no4 #b ,a tumbler is filled with water and a piece of paper placed over the top of it4 ,the glass is then inverted1 holding the hand over the paper so that none of the water will come out4 ,on taking the hand away1 although the glass of water is inverted1 the contents do not leave the glass4 7,see ,fig4 #d47 ,illustration3 ,fig4 #e ,,conclusion ,it demonstrates that the air is exerting a pressure from below on the paper1 which is more than enough to support the weight of the water4 ,the tumbler may be placed in any position and yet the water will stay in4 ,this air pressure is exerted alike from all directions1 and this pressure1 which is #ad4g pounds to the square inch1 is weighed down by the air about it and may be likened very much to ordinary water in that it exerts pressure in all directions4 ,,experiment ,,no4 #c ,take an ordinary rubber sucker1 such as is used on the end of a dart1 and attach it to a string4 ,force this down on a piece of glass4 7,see ,fig4 #e47 ,the glass can then by lifted by the pressure of the air that holds the rubber to it4 ,we are indebted to a ,german experimental philosopher named ,otto ,von ,guericke for knowledge of atmospheric pressure4 ,guericke is distinguished by his original discoveries of the properties of the air4 ,he was born at ,magdeburg in ,prussian ,saxony1 ,november #bj1 #afjb4 ,he became interested at an early age in the politics of his city1 and in #afbg was elected alderman1 and in #afdf ,mayor of ,magdeburg4 ,while serving in the above capacities1 he devoted his leisure to science1 especially on the creation of a vacuum and the action of bodies in a vacuum4 ,his first experiments were conducted with a pump on a barrel of water4 ,after drawing off all the water1 he still found that air permeated the wood of the barrel1 so he substituted a globe of copper and pumped out air also4 ,he thus became the inventor of the air pump and illustrated in a simple but effective way the force of atmospheric pressure4 ,illustration3 ,fig4 #f ,by placing two hollow hemispheres of copper 7see ,fig4 #f7 together1 and exhausting the air1 he found that fifteen horses pulling one way and fifteen pulling the opposite were unable to pull the hemispheres apart4 ,he further demonstrated that in a vacuum all bodies fall equally fast1 that animals cannot exist therein1 or1 in fact1 living matter4 ,he is also credited with being the inventor of the air balance and a type of weather cock1 called the anemoscope4 ,he was interested also in astronomy4 ,illustration3 ,fig4 #g ,,experiment ,,no4 #d ,this experiment should interest you very much1 because it is going to lead up to the subject of weather instruments1 and is absolutely essential that you understand the fundamental principles in order to intelligently interpret these instruments4 ,this experiment will explain one of the principles of the barometer4 ,take a glass tube thirty-two inches long and one-quarter or one-eighth inch in diameter1 and fill it with mercury1 care being used to get rid of all the air bubbles4 ,the mercury should be poured in with an eye dropper1 one end of the tube being sealed1 until filled1 and then the finger is placed over the open end4 7,see ,fig4 #g;,a74 ,the tube is inverted and immersed in a reservoir of mercury and clamped to an upright stand4 ,immediately the mercury falls to about thirty inches4 7,see ,fig4 #g;,b74 ,ask yourself what held the mercury up in the tube4 ,again the answer is that the pressure of the air on the mercury in the reservoir causes it to rise and fall in the tube1 as the pressure of the air changes4 ,you will soon learn what causes these changes in the pressure of the air4 ,illustration3 ,fig4 #h ,,experiment ,,no4 #e ,have you ever asked yourself why it is that the wind blows8 ,why doesn't it stand still8 ,put your hand over a lamp chimney under which the lamp is lighted4 ,you will soon discover that the heat is rising4 ,four things in connection with this are of great importance3 #a4 ,air has weight4 #b4 ,when heated1 it rises4 #c4 ,air expands when heated4 #d4 ,warm air will gather and hold more moisture than cold air4 ,,experiment ,,no4 #f ,cut a piece of stiff cardboard in a spiral shape4 ,thread a piece of thread through a pinhole in the center point of the spiral and fasten this to a support so that it swings freely in the air4 7,see ,fig4 #h47 ,under this put a little alcohol lamp1 or put it over a gas jet or radiator4 ,,what ,,happens ,the cardboard will spin around rapidly4 ,ask yourself what causes this4 ,it is the force of the hot air rising which caused the spiral cardboard to turn in such an attractive manner4 ,,experiment ,,no4 #g ,illustration3 ,fig4 #i ,when you are in a warm room1 find out which air is the hottest1 that in the upper or that in the lower part of the room4 ,this answer you can get by placing the thermometer low down in the room and then putting it up near the ceiling4 ,this is another conclusive proof that hot air rises4 ,another experiment that is quite familiar to all of us is that of opening the windows of a heated room a few inches top and bottom1 and holding a lighted match or smoke paper at the bottom1 when you will find that it blows the flame or smoke inward4 ,then put it near the top of the window and it will be drawn out4 ,the same answer is true2 the cold air is rushing in from below to take the place of the hot air rising and going out at the top4 7,see ,fig4 #i47 ,illustration3 ,fig4 #aj ,,experiment ,,no4 #h ,this experiment is even more important than the preceding one1 and you should by all means do it1 for it is going to prove more conclusively than anything else what causes the wind1 and in miniature it is a real storm4 ,place a little alcohol lamp on the table1 or a wax candle will do4 ,over this place an ordinary lamp chimney1 lifting it a short distance off the table1 and it can be held in position by any little object4 7,see ,fig4 #aj47 ,over the chimney hold some smoke paper4 7,smoke paper is nothing more than filter paper1 or brown wrapping paper of a soft texture47 ,from the experiments already visualized to you1 you should know what to expect4 ,you will again see that the heated air is rising2 it has expanded and become light4 ,now what becomes of the air that is rising and where does it go8 ,in doing this experiment be careful not to make any unnatural movements that will change the current of wind4 ,stand perfectly still so that the experiment will be perfect1 because you are now producing in miniature a real storm1 or demonstrating the cause of wind4 ,the next observation--what happens at the bottom of the chimney8 ,here you will find the outside air is coming in1 the same as it did in the window experiment4 ,particularly1 notice however1 that the smoke enters underneath the chimney from all directions1 and the smoke paper should be moved away from the glass chimney to determine the distance at which the smoke flames will still be drawn into the chimney4 ,you now produced for yourself in miniature a storm and wind4 ,the air that has been heated rises over a heated area1 and cooler air from all directions around is passing into the space underneath the chimney and taking the place of the heated air that has gone up4 ,this experiment illustrates what takes place1 except on a smaller scale1 out in the atmosphere when a portion of the earth becomes heated4 ,if this is clear to you1 it will help you to understand the main principles underlying storms and winds1 which will be given later on4 ,,experiment ,,no4 #i ,equally important is the last part of the experiment1 which consists in lifting the lamp chimney off the table altogether and continuing with the smoke paper4 ,note results that you get now4 ,the smoke will spread out over a large area4 ,,what ,,is ,,the ,,weather8 ,by the weather we mean the temperature1 the amount of moisture in the air1 the pressure of the air1 the movement of the air1 and all the conditions that have to do with the atmosphere1 such as heat1 cold1 rain1 snow1 sleet1 fog1 frost1 dew1 etc4 ,it has to do with everything1 from calmness and clearness to cloudiness and blizzards4 ,,the ,,effect ,,of ,,the ,,sun ,the sun has a great deal to do with the regulation of the weather4 ,its heat causes evaporation2 it is the rays of the sun that raises the vapor from the water and brings it into the air2 it is the cooling of this vapor that produces the rain1 hail and sleet storms1 and its brilliancy causes a difference in air pressure at times4 ,it is this difference in air pressure that produces winds1 as you will learn later4 ,,humidity ,the state of the air with respect to the vapor that it contains is called its humidity4 ,the humidity is said to be high when the air is damp1 and low when the air is dry4 ,humidity and moisture in the air are important factors about the weather4 ,it is lack of humidity that has more to do with poor health1 colds1 and catarrh than anything else4 ,the importance of proper humidity in houses and buildings cannot be emphasized too greatly4 ,proper humidity will save twelve and one-half per cent in the cost of heating4 ,the great majority of people are under the impression that colds are caused by sudden change in temperature1 but the most colds are actually caused by stuffy1 hot rooms4 ,the reason that some people complain that #gj is not hot enough is because the humidity is too low1 but if the moisture is brought into the air at a proper degree1 the humidity is maintained4 ,you will find that #fh will be a proper temperature to maintain in a room4 ,the reason for this is that the air in the room is dry and the heat actually goes through it4 ,in other words1 it does not warm it2 moist air stops radiation4 ,consequently1 the result is that it warms it4 ,in other words1 moisture is nothing more than clothing1 and this accounts for the fact that in a hot room1 where there is no moisture1 we heat our rooms beyond the degree that is necessary in order to feel any reasonable amount of comfort4 ,dry air allows too much radiation from the body and too rapid evaporation1 which makes us cold4 ,the following experiment illustrates the above statement4 ,place a few drops of water on a smooth surface1 such as a table top or ordinary board1 and over this a watch glass1 containing a small quantity of ether4 ,in order to hasten evaporation1 blow a current of air across it1 and it will be found that the glass will be frozen to the board4 ,this is caused by the evaporation of the ether1 which uses up heat4 ,you know a great many times when you go out into the wind how cold it feels1 and yet if the wind would actually stop1 you would think it warm4 ,it is the wind that causes the rapid evaporation and makes the surface of the skin feel cold4 ,as it is true that the moisture in the air acts as a blanket to us in our homes1 it is likewise as true that the vapor in its natural form outside of the house acts as a blanket for the earth4 ,do you realize that without this blanket we would burn up in the summer and freeze to death in the winter8 ,,fogs ,water vapor in the air is transparent1 but when this water vapor becomes cooled1 a portion of it becomes precipitated1 which is no more or less than drops of water that are extremely small1 but yet large enough to become transparent1 and the atmosphere in this state is called fog4 ,in reality1 fogs are nothing more than clouds near the surface of the earth4 ,when the ground is at a higher temperature than the air1 it produces fogs4 ,they are also produced when a current of moist air and a current of hot air pass over a body of water at a lower temperature4 ,consequently1 you can easily see that fog will never form when it is dry4 ,,hail ,after rain drops have been formed and they freeze in their passage through the air1 they then become hailstones4 ,,snow ,when condensation of vapor in the air takes place at a temperature below #cb ,f41 a deposit is made in a solid condition1 either in the form of snow or hail4 ,snow is made up of crystals1 most of which have great beauty4 ,everyone should observe either by the naked eye or by a magnifying glass the little crystals caught before they are broken4 ,when you see extremely large snowflakes in the sky1 you can be sure the temperature is very near freezing1 for at this point the flakes are more or less damp and the snow is heavy and wet4 ,now if there is a slight wind1 the crystals become broken and separate flakes unite to form large masses of snow4 ,generally speaking1 ten inches of snow makes one inch of rain4 ,,dew ,if the temperature of the ground falls below the dew point of the air1 the air deposits on the cooler surface moisture in the form of small drops of water1 which we call dew drops4 ,where the temperature of the ground becomes cooler than the air above it1 a rapid cooling by radiation on a clear night has taken place2 and if the dew point or frost point has been reached by the ground1 the air just above the point is several degrees warmer4 ,,frost ,when the moisture in the air that is in contact with the earth is condensed above the freezing point1 dew is formed4 ,when below the freezing point1 frost is formed or deposited on the earth4 ,it is readily understood from this that the surface on which the frost is deposited is at a freezing temperature1 while the air above it may not be freezing4 ,naturally1 you can expect frost when the temperature falls to a point #h or #aj above the freezing point4 ,clear1 calm nights are favorable for frost1 because the absence of clouds helps radiation1 that is1 it draws heat away from the earth4 ,if there are clouds1 it prevents this radiation4 ,,thunder ,,and ,,lightning ,free electricity is always in the air4 ,during clear weather it is generally positive2 during cloudy weather it is negative4 ,this electricity is carried in the air by the moisture4 ,as dry air is a non-conductor of electricity1 in fair weather the electrified particles of air are insulated and therefore acquire very little intensity4 ,the clouds having been formed and being filled with moisture1 form an excellent conductor of electricity1 which acquires considerable intensity4 ,it is a well-known physical law that two bodies having opposite electricities attract each other1 and those having like charges repel each other4 ,from this1 two clouds having opposite charges rush together and produce the phenomena1 called lightning1 which is accompanied by an explosion called thunder4 ,often we see several flashes of lightning and then hear several thunder crashes1 which is caused by only one section of a cloud discharging its electricity at a time4 ,as a cloud attracts the opposite charge of electricity from the surface of the earth beneath it by inductive influence1 often we see a discharge of electricity from the cloud to the earth1 the charge usually being received by such objects as hills1 trees1 church spires1 high buildings1 etc4 ,bodies containing large quantities of moisture are susceptible to strokes of lightning1 as the moisture causes them to become good conductors of electricity4 ,also trees on the outer edge of a forest are more liable to be struck than those farther in4 ,there are several forms of lightning1 such as zigzag1 ball1 sheet1 and heat lightning4 ,zigzag lightning1 as the name implies1 follows an irregular course1 producing a long zigzag line of light1 sometimes ten miles in length1 and is caused by the air producing a field of resistance to the path of electricity1 causing it to seek a path of less resistance4 ,ball lightning appears like a large ball of fire1 usually accompanied by a terrific explosion4 ,this is the result of the bodies being charged with electricity of great intensity1 and travels in a straight path1 as it has enough strength to oppose any resistance placed in its path4 ,heat lightning is usually seen on warm evenings1 especially during the summer1 and very often unaccompanied by thunder1 due to the great distance of the lightning clouds from where we are located1 thus diminishing the intensity of the thunder4 ,the electricity of the clouds escape in flashes so feeble as to produce no audible sound4 ,sheet lightning is a diffused glare of light sometimes illuminating only the edges of a cloud1 and again spreading over its entire surface4 ,ordinary flashes of lightning last but the minutest part of a second4 ,thunder is the re-entrance of air into an empty space4 ,the vacuum is created by the lightning in its passage through the air4 ,the violence of thunder varies according to the intensity of the electrical flashes4 ,because of the fact that light is transmitted almost instantaneously1 while sound travels at a speed of eleven hundred feet per second1 the sound will not reach the ear for some few seconds after the flash of lightning4 ,average space of time between a flash and a report is about twelve seconds4 ,the longest interval is seventy-two seconds and the shortest one second4 ,prolonged peals of thunder are1 in some cases1 due to the effect of echoes4 ,these peals are especially noticeable in mountainous countries4 ,the echoes are also produced by the reflection of sound from the clouds4 ,thunder storms are distributed over certain sections of the globe1 occurring most frequently in the equatorial regions and diminishing as we approach the polar regions4 ,within the tropics1 where there are trade winds1 thunder storms are rare4 ,thunder storms are common in warm climates because evaporation supplies electricity in great abundance1 and thus precipitation of the air is brought about4 ,illustration3 ,fig4 #aa ,,tornadoes ,tornadoes are caused by the air becoming abnormally heated over certain areas4 ,likewise1 caused by a difference in pressure4 ,tornadoes are local whirlwinds of great energy1 generally formed within thunder storms4 ,they are most easily distinguished by a funnel-shaped cloud that hangs from the bottom of the larger thunder cloud mass above it4 ,the funnel is formed around a violent ascending mass of whirling winds2 its diameter sometimes reaching several hundred feet1 being larger above than below1 the winds themselves covering a greater space4 ,illustration3 ,fig4 #ab ,the whirling funnel advances generally to the east or northeast at a rate of twenty to forty miles an hour1 accompanied by a deafening noise1 destroying everything in its path4 ,the path is usually less than a quarter of a mile in width4 ,the winds in the vortex 7the apparent cavity or vacuum formed in the center of the whirling winds7 of the tornado attain an incredible violence1 and due to this fact houses are shattered1 trees uprooted1 and human lives lost1 besides other devastation of property and animal life4 ,it is1 therefore1 the vorticular whirl that causes the destruction produced by tornadoes4 ,tornadoes are more frequent in the southern states than anywhere else in the country1 and occur in the warmer months4 ,the velocity of the whirling winds in a tornado increase towards the center1 and it is because of this that the point of danger is only a small distance from the funnel cloud4 ,the direction of the whirling motion is from right to left4 ,from the appearance of the funnel formed in a tornado1 it looks as though the currents were descending from the cloud to the earth1 when in reality the currents are ascending4 ,the ascending current draws on the warm and moist air near the surface of the earth for its supply1 and this inrush of air in a spiral form into the low pressure core made by the higher whirl constitutes the destructive blast of the tornado4 ,tornadoes approach rapidly1 and it is therefore almost impossible for those who happen to be in their path to escape their violence4 ,a tornado at sea is termed a water spout4 ,,rainfall ,you will recall a preceding statement that evaporated humidity turns into water when it becomes cool below a certain point4 7,see page #ad1 ,effect of the ,sun47 ,a given amount of air will hold a certain amount of moisture4 ,for example1 let us assume that a cubic foot of air 7see ,fig4 #aa7 is saturated1 that is1 it is holding all the water it will retain4 ,now if this cubic foot of air is cooled1 it will contract1 and as a result there will not be enough room to hold both the air and moisture1 so the excess moisture will leak out4 7,see ,fig4 #ab47 ,the result of this reduction in temperature causes precipitation1 simply because the air cannot sustain the water that is in it4 ,therefor1 at any time when moisture in the air has reached the point of saturation and a chilling takes place1 due to the air becoming cold1 rain follows4 ,this may happen as a result of air rising into higher places or cooler levels1 or through its contact with cooler surfaces4 ,,why ,,we ,,get ,,such ,,heavy ,,rainfalls ,,sometimes ,,around ,,mountains ,the air becomes thoroughly saturated4 ,when air is comparatively warm1 it will expand1 and this air1 which is heavily saturated is brought up by breezes onto the mountain range1 which is cold1 causing the air to lose its heat and contract and really force the water out of the air4 ,the same principle applies to sea breezes bringing rain4 ,,winds ,winds are caused as a result of differences in temperature between the various layers of the atmosphere4 ,a certain amount of air becomes heated and rises1 and as explained before1 expands4 ,as the air expands1 it becomes lighter1 and because it is light it goes upward toward higher regions4 ,it also flows from hot to cold countries4 ,a good illustration of this is the sea breezes4 ,if you have lived around the seashore in the summer time1 you will have observed that during the hot part of the day the winds generally blow from the sea toward the land4 ,at night the direction of the wind is reversed1 that is1 it blows from the land to the sea4 ,why8 ,because the land during the day retains its heat1 while the water diffuses it4 ,what is the result8 ,the air on the land expands1 becomes light4 ,the air over the water being cool1 it does not expand1 and the result is that it presses toward the land4 ,at night the land loses its heat more rapidly than the water1 so that it is not long before the land is cooler than the water1 and when this happens1 the air over the land1 which has become cooler1 presses seaward4 ,,kinds ,,of ,,winds ,mountain ,breezes3 ,caused by the heating and cooling of the hills and valleys4 ,avalanche ,winds3 ,winds that are in front of a landslide1 caused by the movement of the snow forcing the air in front of it4 ,illustration3 ,fig4 #ac ,illustration3 ,fig4 #ad ,illustration3 ,fig4 #ae ,illustration3 ,fig4 #af ,illustration3 ,fig4 #ag ,volcanic ,winds3 ,due to volcanic eruption1 which produces an outrush of air4 ,a ,squall3 ,due to the sudden disturbance in temperature4 ,a ,simoon3 ,a desert wind4 ,,velocity ,,of ,,wind ,the wind blows a great deal harder on water than on land1 because on land it meets with various obstacles1 whereas it has very little friction on the water4 ,,the ,,force ,,of ,,the ,,winds ,wind blowing at #bj miles per hour has a force of #a lbs4 ,wind blowing at #ce miles per hour has a force of #f lbs4 ,wind blowing at #ej miles per hour has a force of #ac lbs4 ,wind blowing at #ge miles per hour has a force of #bh lbs4 ,wind blowing at #ij miles per hour has a force of #dj lbs4 ,,day ,,signals ,illustration3 ,fig4 #ah ,illustration3 ,fig4 #ai ,illustration3 ,fig4 #bj ,illustration3 ,fig4 #ba ,illustration3 ,fig4 #bb ,illustration3 ,fig4 #bc ,,night ,,signals ,illustration3 ,fig4 #ai;,a ,illustration3 ,fig4 #bj;,a ,illustration3 ,fig4 #ba;,a ,illustration3 ,fig4 #bb;,a ,illustration3 ,fig4 #bc;,a ,,name ,,of ,,winds ,beaufort's scale1 used in preparation of all ,weather ,bureau wind forecasts and storm warnings4 ,,force ,,designation ,,miles ,,per ,,hour #j ,calm ,from #j to #c #a ,light ,air ,over #c to #h #b ,light breeze 7or wind7 #h #ac #c ,gentle breeze 7or wind7 #ac #ah #d ,moderate breeze 7or wind7 #ah #bc #e ,fresh breeze 7or wind7 #bc #bh #f ,strong breeze 7or wind7 #bh #cd #g ,moderate gale #cd #dj #h ,fresh gale #dj #dh #i ,strong gale #dh #ef #aj ,whole gale #ef #fe #aa ,storm #fe #ge #ab ,hurricane #ge ,the following method of transmitting weather signals by means of flags was used for a number of years1 but the newspapers now convey the same news to the interested public3 #a4 ,a square white flag indicates fair weather4 7,see ,fig4 #ac47 #b4 ,a square blue flag indicates rain or snow4 7,see ,fig4 #ad47 #c4 ,a white and blue flag1 half white and half blue1 indicates local rain or snow4 7,see ,fig4 #ae47 #d4 ,black triangular flag indicates a change in temperature4 7,see ,fig4 #af47 #e4 ,white flag with a square black center indicates cold wave4 7,see ,fig4 #ag47 ,when ,no4 #d is placed above ,no4 #a1 #b1 or #c1 it indicates warmer weather2 when below1 colder2 when not displayed the temperature is expected to remain stationary4 ,the following flag warnings are used along the ,atlantic and ,gulf coasts to notify inhabitants of this section of the country of impending danger4 ,fig4 #ah4 ,the ,small ,craft ,warning4 ,a red pennant indicates that moderately strong winds that will interfere with the safe operation of small craft are expected4 ,no night display of small craft warnings is made4 ,fig4 #ai4 ,the ,northeast ,storm ,warning4 ,a red pennant above a square red flag with black center displayed by day1 or two red lanterns1 one above the other1 displayed by night 7,fig4 #ai;,a71 indicates the approach of a storm of marked violence1 with winds beginning from the northeast4 ,fig4 #bj4 ,the ,southeast ,storm ,warning4 ,a red pennant below a square red flag with black center displayed by day1 or one red lantern displayed by night 7,fig4 #bj;,a71 indicates the approach of a storm of marked violence with winds beginning from the southeast4 ,fig4 #ba4 ,the ,southwest ,storm ,warning4 ,a white pennant below a square red flag with black center displayed by day1 or a white lantern below a red lantern displayed by night 7,fig4 #ba;,a71 indicates the approach of a storm of marked violence1 with winds beginning from the southwest4 ,illustration3 ,fig4 #bd ,fig4 #bb4 ,the ,northwest ,storm ,warning4 ,a white pennant above a square red flag with black center displayed by day1 or a white lantern above a red lantern displayed by night 7,fig4 #bb;,a71 indicates the approach of a storm of marked violence1 with winds beginning from the northwest4 ,fig4 #bc4 ,hurricane1 or ,whole ,gale ,warning4 ,two square flags1 red with black centers1 one above the other1 displayed by day1 or two red lanterns1 with a white lantern between1 displayed by night 7,fig4 #bc71 indicate the approach of a tropical hurricane1 or of one of the extremely severe and dangerous storms which occasionally move across the ,great ,lakes and ,atlantic ,coast4 ,illustration3 ,fig4 #be ,we have installed at our manufacturing plant a high-class weather station1 with equipment of the latest ,united ,states ,weather ,bureau standard pattern1 and are able to send out weather signals by wireless from our own wireless station twice daily1 at #d ,p4 ,m4 and #g ,p4 ,m41 to all boys owning a wireless outfit4 ,the indications are taken from our own instruments4 ,a description of these instruments and the method of recording the indications will give you an insight into how the various government weather stations arrive at their forecasts4 ,illustration3 ,fig4 #bf ,on the roof of the factory is a weather vane 7,fig4 #cd7 twenty feet high1 which is connected electrically with a register in our weather office4 ,the register is of the quadruple type 7,fig4 #de71 and is capable of recording wind direction1 wind velocity1 rainfall1 and sunshine on the same form or sheet4 ,thus1 we know the wind direction and can deduce certain things relating to the weather4 ,mounted on the wind vane support is an anemometer 7,fig4 #cf71 an instrument for measuring the velocity of the wind4 ,a rain gauge 7,fig4 #di7 on the roof catches the precipitation1 and for every one hundredth of an inch of rainfall1 a small tipping bucket empties its contents into a receiver and a record is made on the form in the quadruple register4 ,the same pen that records the rainfall also records the number of hours of sunshine during a day1 for it is not a common thing to have rain and sunshine at the same time4 ,a hygrothermograph 7,fig4 #dc7 records on a form the temperature and amount of humidity in the atmosphere4 ,a barograph 7,fig4 #dd7 records the pressure of the atmosphere4 ,for determining the pressure1 we also have a mercurial and aneroid barometer1 which will be described later on4 ,you can readily see that it is a simple matter to obtain the weather indications4 ,illustration3 ,fig4 #bg ,,clouds ,the numberless kinds of clouds makes it quite difficult to describe and arrange them or illustrate them in any manner that makes it easy to recognize them4 ,although some may be recognized from description and with a fair amount of observation1 you will be able to classify them in their proper place4 ,for instance1 the thunder clouds most anyone recognizes without any experience whatever4 ,illustration3 ,fig4 #bh ,there are really four simple cloud formations and three compound formations3 #a4 ,the ,cirrus ,cloud4 7,fig4 #bd47 ,the ,cirrus cloud is always seen high in the sky and at a great elevation4 ,its formation is fibrous and it is particularly characterized for its many varieties of shapes4 ,it also has a marked delicacy of substance and it is pure white4 #b4 ,the ,cumulus ,cloud4 7,fig4 #be47 ,the ,cumulus cloud is of moderately low elevation4 ,it is a typical cloud of a summer day4 ,it may be recognized by little heaps or bushes rising from a horizontal base4 ,in summer-time we are all familiar with the cumulus clouds rising with the currents of air in huge masses4 ,they form one of the most accurate indications of fair weather when you see them gradually dissolving4 ,sometimes these clouds become very large1 and1 while the texture is generally of a woolly white1 naturally1 when they assume such large sizes1 they gradually change in color to a darkish tint4 #c4 ,the ,stratus ,cloud4 7,fig4 #bf47 ,this is the opposite of the ,cirrus cloud1 because it hangs the lowest of all1 in gray masses or sheets1 with a poorly-defined outline4 #d4 ,the ,nimbus ,cloud4 7,fig4 #bg47 ,any cloud can be classed as a nimbus cloud from which rain or snow is falling4 ,of the ,compound ,clouds we have3 ,illustration3 ,fig4 #bi #a4 ,the ,cirro-,cumulus ,cloud 7,fig4 #bh71 which has all the characteristics of both the ,cirrus and the ,cumulus4 ,the most characteristic form of this cloud1 and the one most commonly known1 is when these clouds form small round masses1 which appear to be cirrus bands broken up and curled up4 ,this is what people call the 8mackerel0 sky4 #b4 ,the ,cirro-,stratus ,cloud 7,fig4 #bi71 which is known when the clouds arrange themselves in thin horizontal layers at a great elevation4 ,illustration3 ,fig4 #cj #c4 ,the ,cumulo-,stratus 7,fig4 #cj7 is the cumulus and the stratus blended together4 ,their most remarkable form is in connection with approaching thunder storms1 and are often called thunder heads4 ,they rapidly change their outline and present a beautiful spectacle in the sky at times4 ,the ,cirrus1 ,cirro-,cumulus and ,cirro-,stratus are known as the upper clouds and the others are known as the lower4 ,,atmospheric ,,disturbances ,disturbances of the atmosphere are classified as follows3 ,cyclonic1 or low area storms1 or anti-cyclonic1 or high area storms4 ,illustration3 ,fig4 #ca ,the word 8cyclone0 to most people immediately means a terrific storm1 whereas in weather observing the cyclonic storm is not really a cyclone or hurricane at all4 ,it is a storm with an atmospheric pressure below average4 ,particularly important is the wind that blows about this area1 which is always spirally inward1 due to the rotation of the earth on its axis4 ,this is probably why it is given the name of cyclonic storm1 for it bears one of the important characteristics of a real cyclone4 ,as the wind is deflected and moves into the storm center1 it turns to the right and in the form of a whirlwind1 spirally1 moves around the storm center4 7,see ,fig #ca47 ,it is this whirling process that has given it the name1 cyclonic storm4 ,as the air rises over the point of low storm area1 or1 in other words1 the area of low pressure1 and travels into the atmosphere1 it is not permitted to rise to any great height1 because it is always acted upon by the force of gravity and is being pulled back to earth again4 ,we assume that because of this fact1 this rising air which has been pulled back to the earth again piles up in certain places1 causing the barometer to rise4 ,such a center as this is known as a high barometric center or the anti-cyclonic area4 ,here the circulation of the air is exactly opposite to that of the cyclonic area4 ,illustration3 ,fig4 #cb ,we are all more or less acquainted with these anti-cyclonic storms1 because in winter these great masses of air rise up from the warm areas1 pile up1 and form high pressure areas over the mountains of ,canada1 and soon this high pressure works down upon us as blizzards and cold waves4 ,we have described quite minutely the movement of the wind about these points of high pressure and low pressure and have shown you the map and have illustrated the high pressure and low pressure areas1 but there is still another feature that is of great importance to us1 and that is the movement of the storms and the fact that storms have a progressive movement from west to east4 ,these storms move more rapidly in the ,united ,states than elsewhere1 and are more rapid in their movement in winter than in summer4 ,their speed is almost one half again as great4 ,the average velocity of the low area storm in the ,united ,states is about twenty-five miles an hour in ,june1 ,july1 ,august1 and ,september1 and from ,october on they continue to increase4 ,,low ,,pressure ,we can summarize low pressure storms generally in the following manner3 ,they have a wind circulation inward and upward and are elliptical in form4 ,their velocity varies from six hundred to nine hundred miles per day1 moving in the same general direction4 ,they are characterized in their eastern quadrants by cloudy weather1 southerly and easterly winds1 precipitation1 temperature oppressive in summer and abnormally high in winter1 falling barometer1 increasing humidity and followed by clear weather1 rising barometer1 decreasing humidity and falling temperature in the western quadrants4 ,buys ,ballot's law of winds is1 that in the ,northern ,hemisphere if one stands with his back to the wind1 the low barometric pressure will be invariably to the left hand2 in the ,southern ,hemisphere the lowest pressure is always to the right4 ,this law explains one of the characteristics of low pressure storms4 ,,areas ,,of ,,high ,,pressure ,in speaking of low pressure storms we called them storm centers1 because nearly always they are of sufficient intensity to bear that name1 but in high pressure areas we do not speak of them as storm centers4 ,the ,buys ,ballot's law applies to anti-cyclonic as well as cyclonic storms1 that is1 when one's back is to the wind1 the lowest barometric pressure is at the left and the highest at the right4 ,this is probably understood by saying that in the cyclonic storms1 the winds blow inward1 contrary to the hands of a watch1 and in the anti-cyclonic they blow outward1 that is1 in the same direction to the direction of the hands of the watch4 ,in the ,united ,states1 the cyclonic storms are not as frequent as low pressure storms1 and it is safe to say that probably not more than one-third of the entire anti-cyclonic areas can be classed as storm areas4 ,,why ,,air ,,rises ,another very interesting experiment is to secure a long-stemmed glass bulb 7see ,fig4 #cb74 ,arrange this apparatus as illustrated1 with the stem of the bulb immersed in the water4 ,the glass bulb condenses the air4 ,when you first put it into the water nothing happens1 but as soon as you apply heat the air bubbles come out of the end of the tube4 ,this means that the air in the tube has expanded and part of it has come out through the stem of the tube and the remainder is lighter4 ,it is well to remember1 when air is heated it expands and becomes lighter4 ,this fact is extremely important to remember1 because it has a great deal to do with the important instrument1 the barometer1 which is used to measure the pressure of the atmosphere and is an important element in the question of humidity1 as you will learn later4 ,by this time you no doubt have learned that3 #a4 ,air has weight4 #b4 ,heated air expands1 becomes lighter1 and exerts less pressure4 #c4 ,cold air comes from the side to take the place of hot air that rises4 ,when the rays of the sun heat an area of the earth1 the air over such a place expands and becomes lighter1 naturally rising1 and the result of this is that the winds are produced by cool air moving in to take the place of the heated air4 ,this cool air moves in from all directions4 ,when such a thing happens at any point on the earth's surface1 it is known as a storm center1 an area of low pressure4 ,,what ,,is ,a ,,cyclonic ,,storm8 ,because of the rotation of the earth on its axis1 a force arises which tends to deflect to the right all motions in the northern hemisphere1 and to the left all motions in the southern hemisphere4 ,the winds flowing toward the storm center are turned to the right or left and move in a spiral around the storm center4 ,this system of whirling winds around a central region of low pressure produce what is termed a cyclonic storm4 ,storms have a tendency to move in an easterly or northeasterly direction1 and at a rate of from five hundred to seven hundred miles a day4 ,cyclonic storms1 although we look upon them as being very severe1 are very often mild and not of an intensive character4 ,,which ,,way ,,does ,,the ,,wind ,,blow ,,after ,a ,,storm8 ,from the descriptions and experiments preceding1 which illustrate the development of storms1 reference was made only to the winds blowing in toward the storm center4 ,naturally the question comes to your mind3 ,what happens to them after the cold air has taken the place of the warm air8 ,they change to other directions when the storm has passed away4 ,it is because of this fact that we look for a change in weather conditions when the wind changes--a very important sign that you will be interested in later on4 ,it is well to mention here a thing that is going to be very important to us when we study the barometer1 that is1 the pressure of the atmosphere4 ,should the pressure of the air1 which is normally at sea level #ad4g pounds to the square inch1 change1 that is1 become lighter1 it would not exert so much pressure on the column of mercury in the tube of the barometer and the mercury would drop in the tube4 7,see ,fig4 #g47 ,on the other hand1 if the weight of the air was increased1 that is1 if it became heavier1 it would force the mercury to rise in the tube4 ,this should be quite clear to you1 because it is the lightness and heaviness of the air that is going to interest us more particularly than any other part of the subject when we get into the study of the atmospheric changes1 what causes them1 and the indications that lead up to our conclusions4 ,in order that this principle is absolutely clear to you1 you should perform ,experiment #d1 or if you have not facilities for doing it1 it is well to see it performed in any physics laboratory4 ,immediately you ask yourself3 ,if air has such a tremendous pressure as #ad4g pounds to the square inch1 why is it that a weight of air amounting to thirty-five thousand pounds bearing down on the average individual does not cave the body in8 ,simply because air penetrates the body so easily that it exerts as much pressure on the inside as on the outside1 and thereby equalizes itself4 ,for instance1 if you go down into a subway or a caisson 7a water-tight box or chamber within which submarine construction is carried on under great air pressure to keep out the water71 where the pressure is sometimes greater than it is outside1 have you noticed the effect this pressure exerts on the ear drums8 ,as it becomes greater1 you may equalize it by swallowing1 which allows the air to get back of the ear drums through the ,eustachian tubes1 which lead from the mouth to the inner ear4 ,,moisture ,water vapor is always present in the air4 ,,experiment ,,no4 #aj ,expose a piece of dry potash to the air4 ,you will soon discover that the potash will dissolve4 ,it has taken up water from the air4 ,,experiment ,,no4 #aa ,put a piece of ice in a pitcher of water and allow it to stand in a warm room4 ,you will soon notice that little beads of perspiration collect on the outside of the pitcher4 ,this moisture is air being condensed4 ,water vapor is part of the atmosphere4 ,some of it is always present in the air4 ,the amount of vapor that the air can hold depends upon the temperature4 ,when the temperature is warm1 the air will hold more water4 ,for instance1 at #ajj ,f4 a cubic foot of air will hold #ai4gi grains of vapor2 at #hj ,f41 #aj4ie grains2 at #ej ,f41 #d4ji grains1 and #cb ,f41 #b4ag grains4 ,at #cb ,f4 is the freezing point on the ,fahrenheit scale4 ,air containing as much water vapor as it can hold is saturated4 ,if the air is suddenly cooled down1 that is1 if the temperature falls when the air is saturated1 air molecules are contracted1 and it must give up the water1 which produces rain4 ,the ocean and the ,great ,lakes are the source from which the air gets its water4 ,it rises into the air in the form of vapor1 that is1 vapor rising from the surface of the water1 and the wind distributes it over the land4 ,condensation turns it into clouds1 and when it is over-saturated1 or rather1 when the temperature drops and the air is unable to retain any more water1 then it forms into drops of water and falls as rain4 ,when the clouds get into the air1 below the freezing point of the water1 the drops of water are changed into ice crystals or snow flakes4 ,when the ice crystals are just at the point of melting into water1 due to the rise in temperature1 the snowflakes lose their form and the result is sleet4 ,,how ,,can ,,we ,,use ,,these ,,facts8 ,so far we have described1 in a general way1 certain facts about the elements of the air1 such as temperature1 pressure1 humidity1 precipitation1 evaporation1 clouds1 winds1 etc41 and these facts of the elements enter into a very interesting phase of weather observation which we will designate as prophesying without instruments or forecasting by physical science4 ,when we come to the more interesting and scientific part of weather observation1 we will drop the word 8prophecy10 because the instruments that are used to measure these elements are going to indicate certain things to us that will lead you to more definite conclusions4 ,hence1 the following observations are what have given an opportunity to the weather prophet or to those people who have been credited with some mysterious power to prophesy what the weather is going to be4 ,they are not definite or conclusive1 and they cannot always be depended upon1 but they certainly are significant and interesting1 and a description of weather would not be complete without a list in chronological order of a series of phenomena or physical signs of this character that have lead certain men to gain quite a reputation for prophesying what the weather is going to be4 ,illustration3 ,fig4 #cc ,,appearances ,various appearances that come in the sky4 ,for instance1 a good example is in the case of the thunder storm1 which can be determined at least a few hours in advance1 by the movement of the clouds and the forms they take4 ,in every locality there is a direction that clouds take that forecasts bad weather1 and there is a direction that clouds take that forecasts fair weather4 ,when you see a halo about the top of a mountain1 you know that bad weather is expected4 ,the same is true when a halo appears about the moon4 ,this indicates rain1 or if the lower clouds break up and the upper clouds1 or a second light covering of clouds1 are seen above the lower ones1 it speaks for continued bad weather4 ,in some localities if rainy weather is continuing for some time1 and a certain change in wind sets in1 it will indicate that good weather is coming4 ,these observations will be readily understood as being adapted for certain localities and are not general4 ,it is always necessary that the observer adapt himself to these localities and study them1 so that he can make prophecies accordingly4 ,it should be borne in mind that these prophecies are only possible from one day to another4 ,,what ,,the ,,clouds ,,indicate ,when high clouds are seen crossing the sun or the moon in a different direction from the lower clouds1 this indicates change of wind toward the direction of the higher clouds4 ,when you see hard-edged clouds1 look for wind4 ,when you see delicate soft clouds1 look for fine weather and probably moderate breeze or high breeze4 ,when you see gloomy dark clouds in a blue sky1 look for slight winds4 ,when you see a bright blue sky through fine clouds that are soft and delicate1 this indicates fine weather4 ,when you see soft-looking clouds1 you can expect less wind1 but probably rain4 ,but when the clouds become hard and ragged1 tufted and rolling in appearance1 stronger winds are coming4 ,when you see small clouds that are inky looking1 look for rain4 ,when you see light clouds traveling across heavy hard masses of clouds1 this indicates both wind and rain1 but if the light scud clouds are alone1 you may expect wind only4 ,misty clouds forming or hanging over the peaks of hills indicate both wind and rain4 ,if during a rainy spell they ascend or disperse the weather is pretty certain to clear up4 ,if there has been fine weather and you begin to see light streaks in the sky which are distant clouds1 and they continue to increase and grow into cloudiness1 this indicates rain4 ,,sunset ,,as ,,an ,,indication ,when the sun is setting and the sky in the west presents a color of whitish yellow or radiates out at a great height1 rain can be looked for during the next night or day4 ,gaudy colors where clouds are definitely outlined indicate probably wind and rain4 ,before setting1 if the sun looks diffused and the color is a brilliant white1 this forecasts storms4 ,when the sun sets in a slightly purple sky and the color at the zenith is a bright blue1 this indicates fine weather4 ,a red sunset generally indicates good weather1 whereas a ruddy or misty sunset indicates bad weather4 ,,what ,,the ,,sky ,,indicates ,when you see a dark1 dismal sky1 look for rain4 ,a sky with a greenish hue1 described as a sickly-looking sky1 is an indication of both rain and wind4 ,a sailor's sky1 which is red in the morning1 means either wind or rain1 and it makes no difference if the sky is cloudy or clear1 if at sunset it is rosy1 it indicates fine weather4 ,a gray sky in the morning indicates fine weather4 ,when daylight is first seen above a bank of clouds1 look for a good stiff wind4 ,wind is indicated if we have a bright yellow sky in the morning1 and rain is indicated if the sky takes on a pale yellow hue4 ,if the sky turns bright yellow late in the afternoon1 it generally indicates that rain is near at hand4 ,unusual colorations1 particularly of deep intense color1 indicate wind or rain4 ,the following appearances indicate a change in the weather3 ,when the atmosphere is clear and crystalline and the stars appear extremely bright2 when the background of the horizon seems to be pinned up against the foreground2 when the clouds form into delicate white film-like mist way up overhead4 7,fig4 #cc47 ,,what ,,fog ,,and ,,dew ,,indicate ,locality has considerable to do with what the fog indicates4 ,as a rule1 where you have fog1 there is not much wind1 and as a result it does not indicate stormy weather1 unless the fog becomes heavy with overhanging sky1 then it is apt to turn into rain1 but a heavy fog with a light sky indicates fine weather4 ,a fog in the morning generally indicates a fair day4 ,a rising fog is a good indication for fair weather4 ,illustration3 ,courtesy ,julien ,friez ,sons1 ,baltimore1 ,md4 ,fig4 #cd ,illustration3 ,fig4 #ce ,dew is a pretty good sign of fine weather4 ,when you can see and hear with remarkable clearness1 and everything is calm and still1 it is a pretty infallible sign that cold weather is due4 ,frost may be looked for on clear1 calm1 cloudless nights1 when the ground is apt to be cooler than the air4 ,,indications ,,from ,,cirrus ,,clouds ,when these clouds suddenly appear in the sky on a clear summer day1 they indicate wet weather4 ,especially if the weather ends turn upward1 which means that the clouds are coming down4 ,when moisture in the form of little drops cling to vegetation1 it is a pretty good indication that there is apt to be more rain4 ,when the sky assumes the appearance of a gray mass and the sun is observed shining through1 it is a pretty good indication that it will rain before night4 ,when overhead clouds are thick and grayish and the lower surface of them is lumpy1 this is an indication of rain4 ,whirlwinds of dust are also indications of rain4 ,,the ,,moon ,the rings that we see formed about the moon are caused by the delicate white clouds through which the moon is shining4 ,illustration3 ,courtesy ,julien ,friez ,sons1 ,baltimore1 ,md4 ,fig4 #cf ,,the ,,rainbow ,the morning rainbow indicates that a shower is in the west1 but if the rainbow is in the east it indicates that the shower has passed over4 ,,birds ,,and ,,storms ,there are certain actions of birds that indicate many things pertaining to the weather that are interesting4 ,it is probable that their ability to fly into the air gives them a view of the horizon1 that by instinct they have been able to determine the atmospheric changes4 ,for instance1 it is well known that if birds of long flight remain at their base1 it generally foretells a storm4 ,the sudden silence of birds has been referred to a great many times preceding a storm4 ,barnyard fowls do many peculiar things that foretell certain weather conditions4 ,the crow flies low and in great circles1 cawing loudly1 before approaching rain4 ,sometimes the house fly is a pretty good barometer4 ,generally before a storm they seem to light on everything1 particularly persons1 and we call them 8sticky40 ,generally at these times they congregate in swarms4 ,most everyone is familiar with the gnat4 ,they are one of the few insects that gives us indications and good signs1 and when you see them forming in groups and moving along in front of you1 you may expect fair weather4 ,there are many other interesting facts and fairy tales about indications by animals and insects1 but there is nothing scientific about them4 ,it has been demonstrated that there is nothing conclusive to be drawn from such signs1 so we will not attempt to waste pages of this book reiterating these fables4 ,certain actions of insects and animals give indications and enable the weather prophet to prophesy4 ,the spider is a good example of an insect prophet1 and if you will observe him carefully1 you will find that when stormy weather is going to come on he shortens his webs1 and if he anticipates a long1 hard storm1 he not only shortens the strings that hold up the web1 but he strengthens them as well1 and vice-versa1 when he anticipates fine weather1 he lengthens his strands of the web4 ,when you see the spider cease his activities and he hangs pretty close to his home1 which is the center of the web1 you will know that rain is approaching4 ,on the other hand1 if he continues to spread about during a storm1 you can be pretty certain that it is not going to be of very long duration4 ,the frog is a good example of an animal prophet4 ,there is a green frog which has been studied in ,germany1 which will come out of the water when rainy weather or cold is approaching4 ,some observers have placed these frogs in a glass jar with a landing provided so that he can come out of the water when he wants to1 and he is always observed high and dry above the water several hours in advance of a storm4 ,,definite ,,conclusions ,forecasting ,weather by ,means of ,instruments ,the first part of this book may not appeal to you1 if you are of a scientific trend of mind1 but it is quite essential that you possess a knowledge of the fundamentals treated in the earlier pages in order to thoroughly understand the weather instruments we will now describe4 ,these instruments are the scientific means of forecasting what the weather is going to be4 ,they definitely indicate certain things1 and from these indications you are going to be able to draw conclusions and become a scientist or meteorologist4 ,the success that you attain will depend upon the accuracy of the instruments and the care you use in reading them4 ,you will be able to rig up a ,weather ,bureau of your own1 and the use of these instruments will interest anyone in a study of the weather4 ,,the ,,weather ,,vane ,to make a forecast1 it is essential from what we have already written1 to know the direction of the wind1 and to determine the direction we must have a weather vane4 ,it is real important that the vane should be sensitive to the slightest movement of the wind and give actual wind directions4 ,at the same time it must possess the property of steadiness1 so that when it is set up it will be rigid4 ,fig4 #cd shows the standard weather vane used at all ,united ,states ,weather ,bureau ,stations and ,fig4 #ce shows the ,gilbert ,weather ,vane4 ,fig4 #ce4 ,the ,gilbert weather vane consists of a metal arrow pointer and a metal rod eight inches long and five thirty-seconds of an inch in diameter4 ,the rod is fastened by means of a few staples to the side of a pole1 or whatever is to be used as a support for the vane4 ,about three inches from the top of the rod is a collar with set screw1 which is tightened1 and the vane itself is then placed on the rod1 the rod passing through the small angles ,a and ,b1 between the sides of the vane4 ,it will be found that the vane will swing freely on this support1 and by constructing two crosspieces with letters ,n1 ,s1 ,e1 and ,w at each end of the pieces1 of course having ,n pointing directly north1 the vane will swing around and show the direction of the wind4 ,illustration3 ,fig4 #cg ,the standard ,united ,states ,weather ,bureau type hardly needs explanation1 as the illustration clearly shows all parts4 ,it is the old1 reliable1 standard iron1 combined wind vane and anemometer support complete1 twenty feet high2 iron contact box near base1 improved roller bearings for six-foot vane2 latter1 with electrical contacts shown enlarged at the right4 ,the vane is fastened securely to the roof of the building and held in a perfectly vertical position4 ,,the ,,anemometer4 ,fig4 #cf ,it is essential to know the velocity of the wind4 ,this is determined by means of an instrument called the anemometer4 ,fig4 #cf4 ,the ,standard ,u4 ,s4 ,weather ,bureau ,station ,anemometer4 ,this is the well-known standard ,robinson ,anemometer1 now in universal use throughout the world for the registration of wind velocity1 but of the latest improved construction4 ,it records electrically the miles or kilometers1 etc41 of wind movements on a register4 ,the standard pattern as furnished to ,weather ,bureau stations is made of brass1 highly polished and finished1 aluminum 7or copper reinforced7 cups1 steel spindle with hard steel bearings1 a ten-mile or kilometer indicator1 electrical contacts1 etc4 ,illustration3 ,fig4 #ch ,the four hollow hemispherical cups are mounted upon cross-arms at right angles to each other1 with the open sections vertical and facing the same way around the circumference4 ,the cross-arms are on a vertical axis1 which has at its lower end an endless screw4 ,this axis is supported so as to turn with as little friction as possible4 ,the endless screw is in gear with a wheel which moves two dials registering the number of revolutions of the cups4 ,the mechanisms are mounted in a suitable metal case with glass front1 as shown in the illustration1 well protected from the weather1 the whole being designed for outdoor use4 ,illustration3 ,courtesy ,julien ,friez ,sons1 ,baltimore1 ,md4 ,fig4 #ci ,the center of the cups moves with a velocity about one-third that of the wind which puts them in motion4 ,the cups are four inches in diameter4 ,the distance from center of cup to center of rotation or axis is #f4gb inches4 ,assuming that the wind-travel is exactly three times that of the center of the cup1 the dials are marked to register miles of wind travel1 five hundred revolutions of the cups corresponding to a mile4 ,the ratio of wind-travel to travel of cup is in reality variable1 depending on the velocity of the wind4 ,it is less for high than low velocities4 ,it varies also with the dimensions of the instrument1 being different for every different length of arm and diameter of cup4 ,on account of the great interference offered by buildings and other obstructions to the free movement of the wind1 its velocity is much less in the vicinity of these obstructions than beyond2 therefore1 in selecting the location for an anemometer1 preference should be given to the more elevated points in the vicinity of the station1 and some rigid support should be used to raise the instrument as far as practicable above the immediate influence of the office building itself4 ,the support must be set up so that the anemometer on top or on the cross-arm is as nearly vertical as possible4 ,the illustration shows clearly the appearance of an approved ,weather ,bureau pattern combined support for wind instruments1 similar to the one installed at our plant4 ,illustration3 ,fig4 #dj ,illustration3 ,courtesy ,taylor ,instrument ,companies ,rochester1 ,n4 ,y4 ,fig4 #da ,fig4 #cg4 ,the ,gilbert ,anemometer4 ,the ,gilbert ,anemometer consists of a case containing a spindle passing through a worm gear1 which turns a toothed gear4 ,this gear in its rotary motion makes a contact with a brass brush1 which is connected electrically with a flashlight4 ,the cross-arms1 with cups attached1 is placed on the spindle1 and as the wind blows1 it revolves the cups1 causing the contact4 ,the velocity of the wind is determined by counting the flashes for fifteen seconds1 thus giving you the number of miles per hour4 ,for instance1 if light flashes eight times in fifteen seconds1 this signifies that the wind is blowing eight miles an hour4 ,fig4 #ch4 ,how to ,connect the ,gilbert ,anemometer4 ,by referring to the diagram1 you will see that one wire which should be the annunciator wire1 or even a small electric light wire1 is connected from the wire at the anemometer case directly to one side of the lamp socket4 ,another piece of the same size wire connects the other side of the lamp socket to one terminal of your switch4 ,the second terminal of the switch should be connected to an outer post of one dry battery4 ,the inner post of this same dry battery should be connected to the outer post of the second dry battery4 ,complete the circuit by connecting the inner post of the second dry battery to any one of the screws at the bottom of the anemometer case4 ,the lamp used should be a small flashlight battery lamp for use on two and a half to three volts4 ,be sure in making the connections that the ends of your wire are scraped free from insulation and dirt4 ,this can be done by cutting off the insulation with a knife and then rubbing the copper wire bright by a piece of sandpaper or emery cloth1 or even a file4 ,the switch should be left open when you are not taking readings1 in order to prolong the life of your batteries4 ,by unloosening the little screw in the hub of the anemometer vanes1 you can remove them and also take off the brass cap on the anemometer case4 ,this should be taken apart once or twice a month1 and some machine oil used around the bearings to keep them from wearing out too quickly4 ,,the ,,standard ,,electrical ,,sunshine ,,recorder ,,and ,,the ,,gilbert ,,sunshine ,,recorder ,fig4 #ci4 ,the standard sunshine recorder is designed for recording the duration of sunshine electrically1 continuously1 and automatically1 on a register4 ,the instrument is essentially a differential air thermometer in the form of a straight glass tube with cylindrical bulbs at each end1 enclosed in a protecting glass sheath1 with suitable platinum wire electrodes fused in at the center1 the whole mounted in a metal socket on an adjustable support4 ,illustration3 ,courtesy ,taylor ,instrument ,companies1 ,rochester1 ,n4 ,y4 ,fig4 #db ,the base is secured to the support on the roof so that the glass tube points north and south1 with the blackened bulb toward the south and lowermost1 then the tube is inclined at such an angle that the instrument will begin and cease to record sunshine with the proper degree of cloudiness4 ,this inclination should be approximately #de from the vertical4 ,the machine should be adjusted at an hour when the sun is wholly obscured4 ,in temperate and cold climates1 slightly different adjustments will be found necessary at different seasons of the year4 ,fig4 #dj4 ,the ,gilbert ,sunshine ,recorder consists of a metal case1 cylindrical in form1 with a piece of metal turned up on the ends1 dividing the cylinder in half4 ,on each side of the case are small holes through which the sun casts its rays and records its movement and duration on a small piece of blue print paper inside the cylinder1 one piece of paper being in each compartment4 ,when the blue print paper is dipped in water1 it becomes entirely bleached1 with the exception of the path made by the sun1 which shows up in a blue line4 ,illustration3 ,courtesy ,julien ,friez ,sons1 ,baltimore1 ,md4 ,fig4 #dc ,illustration3 ,courtesy ,julien ,friez ,sons1 ,baltimore1 ,md4 ,fig4 #dd ,the sunshine recorder should be set up so that the ends point directly north and south4 ,the holes pierced in the sides of the case are nearer one end than the other4 ,the end that the holes are nearest should be toward the south4 ,it should be held firmly in place4 ,,the ,,barometer ,the barometer is used for measuring the pressure of the atmosphere4 ,the principle of this instrument was first discovered by ,torricelli1 a pupil of ,galileo1 the great ,italian philosopher and scientist1 in #afdc4 ,many and various types of instruments have been made1 but the two most generally used1 especially where accurate indications are desired1 are the mercurial and aneroid barometers4 ,either of these instruments are quite sensitive to changes in the weight or pressure of the earth's atmosphere1 and from their variations we are able to draw conclusions relative to changes in the weather4 ,figs4 ,no4 #da and #db illustrate the standard mercurial and aneroid barometers used most extensively today4 ,a description of these barometers will serve to make the photographs clearer to the readers of this text4 ,,the ,,mercurial ,,barometer 7,fig4 #da7 ,the mercurial barometer in use today is practically the same as that invented by ,torricelli4 ,of course1 many changes have been made in the case containing the tube of mercury1 adding to its attractiveness1 but the principle remains the same4 ,the standard mercurial barometer consists of a straight glass tube about thirty-two or thirty-three inches in length1 hermetically sealed at one end4 ,the tube is of half-inch bore and is filled with chemically pure mercury1 which has been boiled in the tube to insure the total exclusion of all air and moisture4 ,after the tube has been filled1 the open end is immersed in a cistern of mercury4 ,upon immersion the mercury drops in the tube to a height of #bi4ib inches at sea level1 or until counterbalanced by the weight of the surrounding atmosphere pressing upon the surface of the mercury in the cistern4 ,the space in the top of the tube is a perfect vacuum and is called the ,torricellian vacuum4 ,the glass mercury tube is enclosed in a brass case4 ,about two inches from the top of the case is an opening extending down the front and back for a distance of about eight inches4 ,on each side of this opening is a graduated scale1 one side being in inches and the other graduated in centimeters4 ,the opening is fitted with a sliding vernier scale graduated in millimeters1 thus permitting the reading of changes in the height of the mercury column most accurately1 as the sliding vernier may be adjusted to the level of the mercury by means of a thumb screw fitted on the side of the case4 ,the cistern containing the mercury is of glass1 with a soft leather or chamois bottom and an adjusting screw1 used to raise or lower the level of the mercury1 so that it just comes in contact with a small ivory point1 inserted in the top of the cistern1 and which is used to mark the zero of the scale4 ,observations of the changes in the atmospheric pressure should be taken at regular intervals1 and it is necessary to adjust the height of the mercury in the cistern before each observation4 ,this is done by bringing the ivory point in contact with the level of the mercury and then bringing the vernier scale absolutely level with the top of the column of mercury in the tube1 and then take the reading4 ,the mercurial barometer is a very delicate instrument and when once placed in the desired position should not be moved4 ,care should be taken that the room in which the barometer is placed is of nearly uniform temperature1 for if the temperature at the top of the barometer is different than the temperature at the bottom1 of course there will be an effect produced on the changes in the mercury column4 ,all other barometers are set by the mercurial4 ,,the ,,aneroid ,,barometer 7,fig4 #db74 ,the aneroid barometer is so constructed that it contains no liquid whatever1 and thus derives its name from the ,greek compound word 8aneroid10 meaning 8without fluid40 ,the essential parts of the instrument are a metallic case from which the air has been exhausted1 and which contains a spring4 ,the case of elastic metal is fastened to a base plate at the bottom and to the spring at the top4 ,the pressure of the atmosphere causes the case to expand and contract1 thus affecting the spring1 which is connected to a needle or dial1 causing the dial to move around on the scale on the face of the instrument and record the changes4 ,the scale is marked off in inches from #bh to #ca1 and besides a brass hand or pointer1 used to designate the changes in the atmospheric pressure1 there is a small index hand to set over the needle so that the amount of change in a certain period is easily known on consulting the instrument4 ,illustration3 ,courtesy ,julien ,friez ,sons1 ,baltimore1 ,md4 ,fig4 #de ,the dial of the barometer is marked with the words 8,fair10 8,change10 and 8,rain10 etc41 but these words have no significance1 and should be disregarded4 ,for instance1 #bi is marked 8,change02 #cj1 8,fair02 #ca1 8,very dry02 #bh1 8,rain40 ,if the barometer1 which has been standing at #cj4i1 suddenly drops down to #bi4i1 this is positive indication that a storm is approaching1 with strong winds1 yet1 according to the dial on the aneroid1 the reading would be 8,fair40 ,if the barometer were standing at #bh and rose to #bi1 this would actually indicate approach of cold1 dry weather1 and yet on the dial it reads 8,rain40 ,this simply goes to show that the readings on the dial are of no significance whatsoever1 and are not to be relied upon4 ,the aneroid is not as accurate an instrument as the mercurial1 so should be checked up occasionally with the mercurial barometer4 ,illustration3 ,courtesy ,taylor ,instrument ,companies ,rochester1 ,n4 ,y4 ,fig4 #df ,the aneroid type of barometer is also used in altitude work1 but must be compensated before using4 ,this type of barometer possesses several advantages over the mercurial in that it is portable and therefore used for altitude work2 at sea it is used because there is no fluid to become unsettled by the motion of the vessel2 it is used also in observatory work because the action is quicker than the mercurial barometer action1 and sudden changes likely to occur are indicated4 ,,indications ,,from ,,the ,,barometer ,a single observation reading of the barometer is of no significance4 ,readings must be taken at different intervals or the results will be misleading4 ,the important thing about the barometer is to watch the rise and fall1 particularly1 whether it is gradual or rapid4 ,from no single reading can you make an observation or a forecast4 ,a rapid rise indicates that a strong wind is apt to blow4 ,a rapid fall indicates that the weather will be unsettled1 and that strong winds are apt to blow4 ,both indicate a change in the weather1 depending upon many things1 particularly1 however1 the direction from which the wind blows4 ,if an observer stands with the wind blowing on his back1 the area of low barometric pressure will be at his left1 and that of high barometric pressure at his right4 ,with low pressure in the west and high pressure in the east1 the wind will be from the south2 but with low pressure in the east and high pressure in the west1 the wind will be from the north4 ,the barometer rises for northerly winds1 from northwest by the north to eastward1 for dry1 or less wet weather1 for less wind1 or for more than one of these changes--except on a few occasions1 when rain1 hail1 or snow comes from the northward with strong wind4 ,the barometer falls for southerly wind1 from southeast1 by the south1 to the westward1 for wet weather1 for stronger wind1 or for more than one of these changes1 except on a few occasions1 when moderate wind with rain or snow comes from the northward4 ,,relative ,,humidity ,,tables ,per ,cent ,fahrenheit ,temperatures ,difference in ,degrees ,between ,wet and ,dry ,bulb ,thermometers ,read-#a4jb4jc4jd4je4jf4jg4jh4ji4jaj4jaa 4jab4jac4jad4jae4jaf4jag4j ing of ,dry ,bulb ,ther- mom- eter #cb #ij #gi #fi #fj #ej #da #ca #bb #ac #d #cc #ij #hj #ga #fa #eb #db #cc #bd #af #g #cd #ij #ha #gb #fb #ec #dd #ce #bg #ah #i #a #ce #ia #hb #gc #fd #ee #df #cg #bi #bj #ab #d #cf #ia #hb #gc #fe #ef #dh #ci #ca #bc #ad #f #cg #ia #hc #gd #ff #eh #di #da #cc #be #ag #i #a #ch #ia #hc #ge #fg #ei #ea #dc #ce #bg #ai #ab #d #ci #ib #hd #gf #fh #fj #eb #dd #cg #bi #ba #ad #g #dj #ib #hd #gf #fh #fa #ec #df #ch #ca #bc #af #i #b #da #ib #hd #gg #fi #fb #ed #dg #dj #cc #bf #ah #aa #e #db #ib #he #gg #gj #fb #ee #dh #da #cd #bh #ba #ad #g #dc #ib #he #gh #gj #fc #ef #di #dc #cf #bi #bc #af #i #c #dd #ic #he #gh #ga #fd #eg #ea #dd #cg #ca #bd #ah #ab #e #de #ic #hf #gi #ga #fe #eh #eb #de #ci #cc #bf #bj #ad #h #b #df #ic #hf #gi #gb #fe #ei #ec #df #dj #cd #bh #bb #af #aj #d #dg #ic #hf #gi #gc #ff #fj #ed #dg #da #ce #bi #bc #ag #ab #f #a #dh #ic #hg #hj #gc #fg #fj #ed #dh #db #cf #ca #be #ai #ad #h #c #di #ic #hg #hj #gd #fg #fa #ee #di #dc #cg #cb #bf #ba #ae #aj #e #ej #ic #hg #ha #gd #fh #fb #ef #ej #dd #ci #cc #bh #bb #ag #ab #g #b #ea #id #hg #ha #ge #fi #fc #eg #ea #de #dj #ce #bi #bd #ai #ad #i #d #eb #id #hh #ha #ge #fi #fc #eh #eb #df #da #cf #cj #be #bj #ae #aj #f #ec #id #hh #hb #ge #gj #fd #eh #ec #dg #db #cg #cb #bg #bb #ag #ab #g #ed #id #hh #hb #gf #gj #fe #ei #ed #dh #dc #ch #cc #bh #bc #ah #ad #i #ee #id #hh #hb #gf #ga #fe #fj #ee #di #dd #ci #cd #bi #be #bj #ae #aa #ef #id #hh #hb #gg #ga #ff #fa #ee #ej #de #dj #ce #ca #bf #ba #ag #ab #eg #id #hh #hc #gg #gb #ff #fa #ef #ea #df #da #cf #cb #bg #bc #ah #ad #eh #id #hi #hc #gg #gb #fg #fb #eg #eb #dg #db #ch #cc #bh #bd #bj #ae #ei #id #hi #hc #gh #gc #fh #fc #eh #ec #dh #dc #ci #cd #cj #be #ba #ag #fj #id #hi #hd #gh #gc #fh #fc #eh #ec #di #dd #dj #ce #ca #bg #bb #ah #fa #id #hi #hd #gi #gd #fh #fd #ei #ed #ej #de #dj #cf #cb #bh #bd #bj #fb #id #hi #hd #gi #gd #fi #fd #fj #ee #ej #df #da #cg #cc #bi #be #ba #fc #ie #ij #hd #gi #gd #gj #fe #fj #ef #ea #dg #db #ch #cd #cj #bf #bb #fd #ie #ij #he #gi #ge #gj #ff #fa #ef #eb #dh #dc #ci #ce #ca #bg #bc #fe #ie #ij #he #hj #ge #gj #ff #fb #eg #ec #dh #dd #dj #cf #cb #bh #be #ff #ie #ij #he #hj #gf #ga #ff #fb #eh #ec #di #de #da #cg #cc #bi #bf #fg #ie #ij #he #hj #gf #ga #fg #fb #eh #ed #ej #df #db #ch #cd #cj #bg #fh #ie #ij #he #ha #gf #gb #fg #fc #ei #ee #ea #dg #dc #ci #ce #ca #bh #fi #ie #ij #hf #ha #gg #gb #fh #fd #ei #ee #ea #dg #dd #dj #cf #cb #bi #gj #ie #ij #hf #ha #gg #gb #fh #fd #fj #ef #eb #dh #dd #dj #cg #cc #cj #ga #ie #ij #hf #hb #gg #gc #fi #fd #fj #ef #ec #di #de #da #ch #cd #ca #gb #ie #ia #hf #hb #gh #gc #fi #fe #fa #eg #ec #di #df #db #ci #ce #cb #gc #ie #ia #hf #hb #gh #gc #fi #fe #fa #eh #ed #ej #df #dc #dj #cf #cc #gd #ie #ia #hf #hb #gh #gd #gj #ff #fb #eh #ed #ea #dg #dd #dj #cg #cd #ge #if #ia #hg #hb #gh #gd #gj #ff #fc #ei #ee #ea #dh #dd #da #ch #cd #gf #if #ia #hg #hc #gh #gd #gj #fg #fc #ei #ee #eb #dh #de #db #ch #ce #gg #if #ia #hg #hc #gi #ge #ga #fg #fc #fj #ef #eb #di #df #db #ci #cf #gh #if #ia #hg #hc #gi #ge #ga #fg #fd #fj #eg #ec #ej #df #dc #dj #cg #gi #if #ia #hg #hc #gi #ge #ga #fh #fd #fj #eg #ed #ej #dg #dd #da #cg #hj #if #ia #hg #hc #gi #gf #gb #fh #fd #fa #eg #ed #ea #dg #dd #da #ch #hb #if #ib #hh #hd #hj #gf #gb #fi #fe #fb #eh #ee #eb #di #df #dc #dj #hd #if #ib #hh #hd #hj #gg #gc #gj #ff #fc #ei #ef #ec #ej #dg #dd #da #hf #if #ib #hh #he #ha #gg #gd #gj #fg #fc #fj #eg #ed #ea #dh #de #db #hh #if #ib #hh #he #ha #gh #gd #ga #fg #fd #fa #eh #ee #eb #di #df #dc #ij #if #ib #hi #he #ha #gh #ge #ga #fh #fe #fb #ei #ef #ec #ej #dg #dd #ib #if #ib #hi #he #hb #gh #ge #gb #fi #fe #fb #ei #eg #ed #ea #dh #de #id #if #ic #hi #hf #hb #gi #ge #gb #fi #ff #fc #fj #eg #ed #eb #di #df #if #if #ic #hi #hf #hb #gi #gf #gc #gj #fg #fd #fa #eh #ee #ec #ej #dg #ih #if #ic #hi #hf #hc #gi #gf #gc #gj #fg #fd #fa #ei #ef #ec #ea #dh #ajj #if #ic #ij #hf #hc #hj #gg #gd #ga #fh #fe #fb #ei #eg #ed #eb #di ,illustration3 ,courtesy ,taylor ,instrument ,companies1 ,rochester1 ,n4,y4 ,fig4 #dg ,like the hygrometer1 this instrument measures the 8relative humidity40 ,illustration3 ,fig4 #dh ,,gilbert ,,hygrometer ,,general ,,barometer ,,indications ,a gradual but steady rise indicates settled fair weather4 ,a gradual but steady fall indicates unsettled or wet weather4 ,a very slow rise from a low point is usually associated with high winds and dry weather4 ,a rapid rise indicates clear weather with high winds4 ,a very slow fall from a high point is usually connected with wet and unpleasant weather without much wind4 ,the following table of the ,united ,states ,weather ,bureau gives a summary of the wind and barometer indications3 ,barometer ,reduced to ,sea ,level ,wind ,character of ,weather ,indicated ,direction #cj4aj to #cj4bj and steady ,,sw to ,,nw ,fair with slight temperature changes for #a to #b days #cj4aj to #cj4bj and rising ,,sw to ,,nw ,fair1 followed within #b days rapidly by warmer and rain #cj4aj to #cj4bj and falling ,,sw to ,,nw ,warmer1 with rain in #bd to #cf slowly hours #cj4aj to #cj4bj and falling ,,sw to ,,nw ,warmer1 with rain in #ah to #bd rapidly hours #cj4bj and above and stationary ,,sw to ,,nw ,continued fair1 with no decided temperature change #cj4bj and above and falling ,,sw to ,,nw ,slowly rising temperature and slowly fair for two days #cj4aj to #cj4bj and falling ,s to ,,se ,rain within #bd hours slowly #cj4aj to #cj4bj and falling ,s to ,,se ,wind increasing in force1 with rapidly rain within #ab to #bd hours #cj4aj to #cj4bj and falling ,,se to ,,ne ,rain in #ab to #ah hours slowly #cj4aj to #cj4bj and falling ,,se to ,,ne ,increasing wind1 with rain rapidly within #ab hours #cj4aj and above and falling ,e to ,,ne ,in summer1 with light winds1 slowly rain may not fall for several days4 ,in winter1 rain within #bd hours #cj4aj and above and falling ,e to ,,ne ,in summer1 rain probably rapidly within #ab to #bd hours4 ,in winter1 rain or snow1 with increasing wind will often set in1 when the barometer begins to fall and the wind sets in from the ,,ne #cj or below and falling slowly ,,se to ,,ne ,rain will continue #a or #b days #cj or below and falling ,,se to ,,ne ,rain1 with high wind1 followed rapidly within #bd hours by clearing and cooler #cj or below and rising slowly ,s to ,,sw ,clearing within a few hours and continued fair for several days #bi4hj or below and falling ,s to ,e ,severe storm of wind and rain rapidly or snow imminent1 followed within #bd hours by clearing and colder #bi4hj or below and falling ,e to ,n ,severe northeast gales and rapidly heavy rain or snow1 followed in winter by a cold wave #bi4hj or below and rising ,going to ,clearing and colder rapidly ,w ,a sudden fall indicates a sudden shower or high winds1 or both4 ,illustration3 ,courtesy ,julien ,friez ,son ,baltimore1 ,md4 ,fig4 #di ,u4 ,s4 ,,standard ,,rain ,,gauge ,a stationary barometer indicates a continuance of existing weather conditions4 7,note3 ,tap the barometer slightly on the face4 ,if the hands move a trifle1 it indicates that there is the tendency to rise or fall1 depending upon the direction of movement of the hands47 ,northeasterly winds precede storms that approach from the southwest2 that is1 in ,new ,england and the ,middle ,states and the ,ohio ,valley4 ,southeasterly winds precede storms that approach from the ,lake region4 ,,thermometers ,for information regarding the manufacture of thermometers1 we recommend ,p4 ,r4 ,jameson's book1 8,weather and ,weather ,instruments10 published by the ,taylor ,instrument ,companies of ,rochester1 ,n4 ,y4 ,thermometers are of great importance to us in determining weather4 ,,location ,,of ,,thermometers #a4 ,they must be properly exposed4 #b4 ,a good circulation of air around them is necessary4 #c4 ,they must be properly protected from the rays of the sun4 ,note3 ,if these instructions are not carefully followed out1 errors are apt to occur1 and you will be misled4 ,for a change of wind towards northerly directions1 a thermometer falls4 ,for a change of wind toward southerly directions a thermometer rises4 ,illustration3 ,fig4 #ej ,,gilbert ,,rain ,,gauge ,,maximum ,,and ,,minimum ,,thermometers ,maximum and minimum thermometers are used to record the daily maximum and minimum temperatures4 ,fig4 #df shows a typical maximum and minimum thermometer used for giving the extremes of temperature4 ,one side of the thermometer has a scale reading1 beginning at the top1 from #fj below zero to #adj above zero4 ,this is the scale used when determining the coldest temperature reached during a day4 ,the other side of the thermometer has a scale marked from #gj below zero1 beginning at the bottom and reading up1 to #acj above zero4 ,on this side the maximum heat reached during the day is recorded4 ,there is a small metal piece in the tubes1 one on each side1 and as the mercury pushes ahead or recedes1 the small index is left at the lowest point reached in one tube and at the highest point reached in the other4 ,the small metal piece is drawn back to the level of the mercury by means of a small magnet4 ,,when ,,maximum ,,temperature ,,is ,,reached ,you can generally look for maximum temperature between three and four o'clock in the afternoon4 ,at this time the sun has reached its highest altitude4 ,illustration3 ,courtesy ,julien ,friez ,sons1 ,baltimore1 ,md4 ,fig4 #ea ,,tipping ,,bucket ,,rain ,,gauge ,,when ,,the ,,minimum ,,temperature ,,is ,,reached ,this usually occurs a little while before sunrise4 ,it is important in weather observing to make a record of the highest temperature of the day and the lowest temperature of the night4 ,continuous observation1 as the reader will appreciate1 is practically impossible for such a record4 ,,the ,,thermometer ,,for ,,humidity ,,in ,,the ,,air ,moisture or dampness in the air1 as shown by an instrument called the hygrometer1 increases before rain1 fog1 or dew4 ,before describing the hygrometer1 a definition of a few of the terms used in conjunction with the instrument will be found useful4 ,,absolute ,,humidity ,the amount of vapor actually present in the atmosphere is termed the absolute humidity1 expressed usually either in the expansive force that the vapor exerts or in its weight in grains per cubic foot of air4 ,,relative ,,humidity ,the absolute humidity divided by the amount of vapor that might exist if the air were saturated gives a ratio that is called the relative humidity4 ,,dew ,,point ,the temperature at which moisture begins to be condensed on a cold vessel or other container and becomes visible is called the dew point4 ,,how ,,hygrometers ,,are ,,made ,the most generally used hygrometer consists of two ordinary thermometers1 the bulb of one being covered with a piece of muslin and kept constantly moistened with water by means of a wick or cotton thread communicating with a container of water4 ,the difference in the readings of the two thermometers1 the wet and the dry1 is observed1 and knowing this1 it is very easy to determine the humidity by consulting a table 7see table on pages #eh-ei71 which has been prepared for this purpose4 ,these instruments are1 according to the increase in price1 equipped with a table1 and the container is held in a wire frame1 as you will see from the ,figs4 #di-ej showing the standard ,weather ,bureau station instrument and the ,gilbert hygrometer4 ,fig4 #di shows the ,u4 ,s4 ,standard ,weather ,bureau ,station ,rain ,gauge1 ,fig4 #ej the ,gilbert ,rain ,gauge and ,fig4 #ea the ,u4 ,s4 ,standard ,weather ,bureau ,station ,rain ,gauge1 ,tipping ,bucket ,type4 ,the ,gilbert ,weather ,station is equipped with the ,tipping ,bucket ,type ,rain ,gauge4 ,fig4 #ea shows the apparatus clearly1 complete and mounted ready for use4 ,the brass bucket seen in position through the open door is adjusted to tip for each hundredth inch of rainfall collected in the twelve-inch diameter receiver at the top1 and this rainfall is electrically recorded at any convenient distance on a register4 ,after any desired period the water may be drawn off and check measurements made by means of the brass measuring tube and graduated cedar stick shown in the figure4 ,,the ,,gilbert ,,rain ,,gauge 7,fig4 #ej74 7a7 ,tube4 7b7 ,funnel4 7c7 ,measuring stick4 ,the essential parts of the ,gilbert ,rain ,gauge consists of a metal tube twelve inches long1 having a diameter of #a inches 7inside7 and a funnel-shaped top1 the neck of which fits snugly into the open end of the metal tube4 ,the outside diameter of the neck of the funnel is a trifle less than #a inches4 ,the area of the circle formed at the top of the tube is one-tenth the area of the funnel circle4 ,a measuring stick is provided to measure the rainfall collected in the tube4 ,to determine the amount of rainfall on the surface of the ground1 the rain collected in the tube should be measured at regular intervals1 usually twelve hours apart4 ,for every inch of rain collected in the tube1 as denoted by the measuring stick1 it means that there is one one-tenth of an inch of rain on the ground2 if #aj inches of rain in the tube1 it signifies one inch of rain on the ground4 ,in other words1 divide the figure recorded on the measuring stick by ten for actual rainfall4 ,it is well to put some sort of a shelter around the gauge1 so that it will be protected from strong winds4 ,the shelter is usually placed at a distance from the tube equal to the height of the tube4 ,with the ,gilbert rain gauge it is well to erect the shelter at a distance of about three feet from the tube4 ,it is essential that the gauge be held in an upright position1 so it should be fastened to the roof4 ,snow is measured by melting the quantity collected in the gauge and follow the same procedure as in rainfall measurements4 ,there is another very common method1 called ground measurement4 ,there are many instances where ground measurements are inaccurate3 #a4 ,when snow and rain are mixed or alternate4 #b4 ,when melting accompanies snowfall4 #c4 ,when snow is already upon the ground4 #d4 ,when the amount of fall is very small4 #e4 ,when drifting is very bad4 #f4 ,when the snow is blown about after the storm and before measurements have been made4 ,a bucket and a spring balance are used4 ,the bucket is filled with snow1 but not packed down too hard1 and weighed4 ,the reading of the index hand on the spring balance gives the density of the snow4 ,the depth of the snow in the vicinity of the spot from which the bucket was filled is obtained and this figure is multiplied by the density1 thus giving the water equivalent of the snow collected4 ,for instance1 if the reading of the balance was 4#af1 and the depth of the snow was #g inches1 multiply 4#af by #g1 and the result1 #a4ab1 is the water equivalent of the snow4 ,,thermometer ,,scales ,the first thermometer scale to give satisfaction was devised in #agad by ,fahrenheit4 ,he determined the fixed points on the thermometer in a very novel manner4 ,having been born at ,dantzig1 he took for the zero point on his scale the lowest temperature observed by him at ,dantzig1 which he found was that produced by mixing equal quantities of snow and sal-ammoniac4 ,the space between this point and that to which the mercury rose at the temperature of boiling water he divided into #bab parts4 ,he determined1 with his thermometer1 that the atmospheric pressure governed the boiling point of water4 ,today the ,fahrenheit thermometer is used extensively1 and has for its freezing point #cb and for its boiling point #bab4 ,another scale that has not become too well known1 because of the fact that it did not meet with public favor1 was devised by a ,frenchman1 named ,reaumur1 in #agcj1 and bears his name4 ,he determined the freezing point of the scale at #j and the boiling point of water at #hj4 ,another ,frenchman1 named ,anders ,celsius1 devised a scale with the boiling point of water at #j and the freezing point at #ajj4 ,in #agdc a ,frenchman1 named ,christin1 living at ,lyons1 ,france1 reversed the points1 and today the scale is known as the ,centigrade scale1 and1 together with the ,fahrenheit scale1 is used almost exclusively wherever thermometers are required4 ,,how ,,to ,,change ,,one ,,scale ,,into ,,another ,centigrade degrees into ,fahrenheit3 multiply by #i1 divide the product by #e and add #cb4 ,fahrenheit degrees into ,centigrade3 subtract #cb1 multiply by #e1 and divide by #i4 ,reaumur degrees into ,fahrenheit3 multiply by #i1 divide by #d1 and add #cb4 ,fahrenheit degrees into ,reaumur3 subtract #cb1 multiply by #d1 and divide by #i4 ,reaumur degrees into ,centigrade3 multiply by #e and divide by #d4 ,centigrade degrees into ,reaumur3 multiply by #d and divide by #e4 ,,weather ,,bureau ,,stations ,,of ,,the ,,united ,,states ,,and ,,weather ,,bureau ,,maps ,the following is a list of the ,weather ,bureau ,stations of the ,united ,states1 and from any of these offices1 preferably the one nearest you1 you will be able to obtain the weather reports and weather map 7see ,fig4 #eb71 indicating many things of interest1 and from which you will be able to make a careful study of the weather4 ,,abilene1 ,,tex4 ,,albany1 ,n4 ,y4 ,,alpena1 ,,mich4 ,,amarillo1 ,,tex4 ,,anniston1 ,,ala4 ,,asheville1 ,n4 ,c4 ,,atlanta1 ,,ga4 ,,atlantic ,,city1 ,n4 ,j4 ,,augusta1 ,,ga4 ,,baker1 ,,ore4 ,,baltimore1 ,,md4 ,,bentonville1 ,,ark4 ,,binghamton1 ,n4 ,y4 ,,birmingham1 ,,ala4 ,,bismarck1 ,n4 ,d4 ,,block ,,island1 ,r4 ,i4 ,,boise1 ,,ida4 ,,boston1 ,,mass4 ,,broken ,,arrow1 ,,okla4 ,,buffalo1 ,n4 ,y4 ,,burlington1 ,,vt4 ,,cairo1 ,,ill4 ,,canton1 ,n4 ,y4 ,,cape ,,henry1 ,,va4 ,,cape ,,may1 ,n4 ,j4 ,,charles ,,city1 ,,ia4 ,,charleston1 ,s4 ,c4 ,,charlotte1 ,n4 ,c4 ,,chattanooga1 ,,tenn4 ,,cheyenne1 ,,wyo4 ,,chicago1 ,,ill4 ,,cincinnati1 ,,ohio ,,clallam ,,bay1 ,,wash4 ,,cleveland1 ,,ohio ,,columbia1 ,,mo4 ,,columbia1 ,s4 ,c4 ,,columbus1 ,,ohio ,,concord1 ,n4 ,h4 ,,concordia1 ,,kans4 ,,corpus ,,christi1 ,,tex4 ,,dallas1 ,,tex4 ,,davenport1 ,,ia4 ,,dayton1 ,,ohio ,,del ,,rio1 ,,tex4 ,,denver1 ,,colo4 ,,des ,,moines1 ,,ia4 ,,detroit1 ,,mich4 ,,devils ,,lake1 ,,no4 ,,dak4 ,,dodge ,,city1 ,,kans4 ,,drexel1 ,,neb4 ,,dubuque1 ,,ia4 ,,duluth1 ,,minn4 ,,eastport1 ,,me4 ,,elkins1 ,w4 ,,va4 ,,ellendale1 ,,no4 ,,dak4 ,,el ,,paso1 ,,tex4 ,,erie1 ,,pa4 ,,escanaba1 ,,mich4 ,,eureka1 ,,cal4 ,,evansville1 ,,ind4 ,,fort ,,smith1 ,,ark4 ,,fort ,,wayne1 ,,ind4 ,,fort ,,worth1 ,,tex4 ,,fresno1 ,,cal4 ,,galveston1 ,,tex4 ,,grand ,,haven1 ,,mich4 ,,grand ,,junction1 ,,colo4 ,,grand ,,rapids1 ,,mich4 ,,green ,,bay1 ,,wis4 ,,greenville1 ,s4 ,c4 ,,groesbeck1 ,,tex4 ,,hannibal1 ,,mo4 ,,harrisburg1 ,,pa4 ,,hartford1 ,,conn4 ,,hatteras1 ,n4 ,c4 ,,havre1 ,,mont4 ,,helena1 ,,mont4 ,,honolulu1 ,,hawaii ,,houghton1 ,,mich4 ,,houston1 ,,tex4 ,,huron1 ,,so4 ,,dak4 ,,independence1 ,,cal4 ,,indianapolis1 ,,ind4 ,,iola1 ,,kans4 ,,ithaca1 ,n4 ,y4 ,,jacksonville1 ,,fla4 ,,juneau1 ,,alaska ,,kalispell1 ,,mont4 ,,kansas ,,city1 ,,mo4 ,,keokuk1 ,,iowa ,,key ,,west1 ,,fla4 ,,kilauea1 ,,hawaii ,,knoxville1 ,,tenn4 ,,la ,,crosse1 ,,wis4 ,,lander1 ,,wyo4 ,,lansing1 ,,mich4 ,,leesburg1 ,,ga4 ,,lewiston1 ,,idaho ,,lexington1 ,,ky4 ,,lincoln1 ,,neb4 ,,little ,,rock1 ,,ark4 ,,los ,,angeles1 ,,cal4 ,,louisville1 ,,ky4 ,,ludington1 ,,mich4 ,,lynchburg1 ,,va4 ,,macon1 ,,ga4 ,,madison1 ,,wis4 ,,manteo1 ,n4 ,c4 ,,marquette1 ,,mich4 ,,memphis1 ,,tenn4 ,,meridian1 ,,miss4 ,,miami1 ,,fla4 ,,milwaukee1 ,,wis4 ,,minneapolis1 ,,minn4 ,,mobile1 ,,ala4 ,,modena1 ,,utah ,,montgomery1 ,,ala4 ,,mount ,,tamalpais1 ,,cal4 ,,nantucket1 ,,mass4 ,,nashville1 ,,tenn4 ,,neah ,,bay1 ,,wash4 ,,new ,,haven1 ,,conn4 ,,new ,,orleans1 ,,la4 ,,new ,,york1 ,n4 ,y4 ,,norfolk1 ,,va4 ,,northfield1 ,,vt4 ,,north ,,head1 ,,wash4 ,,north ,,platte1 ,,neb4 ,,oklahoma1 ,,okla4 ,,omaha1 ,,neb4 ,,oswego1 ,n4 ,y4 ,,palestine1 ,,tex4 ,,parkersburg1 ,w4 ,,va4 ,,pensacola1 ,,fla4 ,,peoria1 ,,ill4 ,,philadelphia1 ,,pa4 ,,phoenix1 ,,ariz4 ,,pierre1 ,,so4 ,,dak4 ,,pittsburgh1 ,,pa4 ,,pocatello1 ,,idaho ,,point ,,reyes ,,light1 ,,cal4 ,,port ,,angeles1 ,,wash4 ,,port ,,arthur1 ,,tex4 ,,port ,,huron1 ,,mich4 ,,portland1 ,,me4 ,,portland1 ,,ore4 ,,providence1 ,r4 ,i4 ,,pueblo1 ,,colo4 ,,raleigh1 ,n4 ,c4 ,,rapid ,,city1 ,,so4 ,,dak4 ,,reading1 ,,pa4 ,,red ,,bluff1 ,,cal4 ,,reno1 ,,nev4 ,,richmond1 ,,va4 ,,rochester1 ,n4 ,y4 ,,roseburg1 ,,ore4 ,,roswell1 ,,new ,,mex4 ,,royal ,,center1 ,,ind4 ,,sacramento1 ,,cal4 ,,saginaw1 ,,mich4 ,,st4 ,,joseph1 ,,mo4 ,,st4 ,,louis1 ,,mo4 ,,st4 ,,paul1 ,,minn4 ,,salt ,,lake ,,city1 ,,utah ,,san ,,antonio1 ,,tex4 ,,san ,,diego1 ,,cal4 ,,sand ,,key1 ,,fla4 ,,sandusky1 ,,ohio ,,sandy ,,hook1 ,n4 ,j4 ,,san ,,francisco1 ,,cal4 ,,san ,,jose1 ,,cal4 ,,san ,,juan1 ,,porto ,,rico ,,san ,,luis ,,obispo1 ,,cal4 ,,santa ,,fe1 ,,new ,,mex4 ,,sault ,,sainte ,,marie1 ,,mich4 ,,savannah1 ,,ga4 ,,scranton1 ,,pa4 ,,seattle1 ,,wash4 ,,sekiou1 ,,wash4 ,,sheridan1 ,,wyo4 ,,shreveport1 ,,la4 ,,sioux ,,city1 ,,iowa ,,spokane1 ,,wash4 ,,springfield1 ,,ill4 ,,springfield1 ,,mo4 ,,syracuse1 ,n4 ,y4 ,,tacoma1 ,,wash4 ,,tampa1 ,,fla4 ,,tatoosh ,,island1 ,,wash4 ,,taylor1 ,,tex4 ,,terre ,,haute1 ,,ind4 ,,thomasville1 ,,ga4 ,,toledo1 ,,ohio ,,tonopah1 ,,nev4 ,,topeka1 ,,kans4 ,,trenton1 ,n4 ,j4 ,,twin1 ,,wash4 ,,valentine1 ,,neb4 ,,vicksburg1 ,,miss4 ,,wagon ,,wheel ,,gap1 ,,colo4 ,,walla ,,walla1 ,,wash4 ,,wichita1 ,,kans4 ,,williston1 ,,no4 ,,dak4 ,,wilmington1 ,n4 ,c4 ,,winnemucca1 ,,nev4 ,,wytheville1 ,,va4 ,,yankton1 ,,so4 ,,dak4 ,,yellowstone ,,park1 ,,wyo4 ,,yuma1 ,,ariz4 ,you will notice that on this map different lines are drawn3 ,first1 the ,isobar lines--these are solid lines drawn through places which have the same barometric pressure4 ,second1 the ,isotherm lines--these are dotted lines drawn through places having the same temperature4 ,the ,weather ,bureau ,maps are gotten out on the same day all over the country1 and the preparation of them is quite interesting4 ,at #g3dj ,a4 ,m4 simultaneous readings are taken at all weather bureau stations of the country4 ,on the coast1 where the time is three hours different than at ,new ,york1 the readings are taken at #d3dj1 so that the hour corresponds at all places4 ,at #h3jj ,a4 ,m4 the various stations telephone their findings to the ,western ,union ,office located in their city and immediately the messages are transmitted by ,western ,union to a central district office1 or circuit center as it is called4 ,for ,new ,england1 the circuit center is ,boston4 ,all messages are received at this office1 and from here transmitted to the next office1 which is ,new ,york1 and from ,new ,york to the next center1 until the news is transmitted to the coast4 ,the wires are open from #h3jj until #i3cj ,a4 ,m4 ,the western offices follow the same procedure until the weather indications are received by all stations4 ,immediately the preparation of the map is begun and they are mailed to interested parties by the ,weather ,bureau ,stations of the ,united ,states4 ,figs4 #eb1 #ec and #ed show three maps1 typifying storms traveling from the west to the east1 and by studying them on successive days you can at once grasp the importance of studying the weather from these maps4 ,fig4 #ec shows a storm of low pressure and how this area of low pressure is progressing and moving from the west to the east4 ,particular notice should be taken of how fast the storm travels1 that is1 the distance it goes each day1 and the direction it is going and the results4 ,illustration3 ,fig4 #eb ,illustration3 ,fig4 #ec ,illustration3 ,fig4 #ed ,the arrows denote the direction of the wind1 and you will notice they point to the region of low barometric pressure4 ,in the regions of high barometric pressure the winds are in the opposite direction4 ,this readily explains to you why it is that you can expect changes in weather conditions when the wind changes4 ,from the markings and printed matter on each map1 information is secured regarding observations of the barometer1 thermometer1 wind velocity1 direction of the wind1 kind of clouds1 and their movements1 and the amount of precipitation 7rain or snow71 in different localities4 ,,how ,,the ,,state ,,of ,,the ,,weather ,,is ,,indicated ,clear1 partly cloudy1 cloudy1 rain or snow indications are symbolized4 ,the shaded area designates places or areas where precipitation has occurred during the preceding twelve hours4 ,,what ,,the ,,words 8,,high0 ,,or 8,,low0 ,,mean ,,on ,,the ,,map ,low barometric pressure1 or the storm centers1 are indicated on the map by the word 8low40 ,high barometric pressure centers are indicated by the word 8high40 ,note how they move in an easterly direction2 how they are progressive4 ,they can be compared to a series of waves1 which we will call atmospheric waves4 ,the crest of the wave may be likened to the 8highs0 and the troughs to the 8lows40 ,usually the winds are southerly or easterly and therefore warmer in advance of a 8low40 ,when the 8lows0 progress east of a place1 the wind generally shifts to westerly and the temperature lowers4 ,the westward advance of the 8lows0 is preceded by precipitation1 and almost always in the form of rain or snow1 following which the weather is generally clear4 ,note how a 8low0 is followed by a 8high10 and so on as they move along eastwardly4 ,,what ,,isotherms ,,indicate ,if the ,isotherms run nearly parallel1 that is1 east and west1 there will most likely be no change in the temperature4 ,southerly to east winds prevail west of the nearly north and south line1 passing through the middle of a 8high0 and also east of a like line passing through the middle of a 8low40 ,to the west of a nearly north and south line passing through the middle of a 8low10 northerly to westerly winds prevail4 ,we will find the same condition prevailing to the east of a line passing through the center of a 8high40 ,illustration3 ,fig4 #ee ,when we find an absence of decidedly energetic 8lows0 and 8highs10 this is an indication of the continuance of existing weather4 ,we can expect this state of the atmosphere until later maps show a beginning of a change1 usually first appearing in the west4 ,,tracks ,,of ,,storms ,,in ,,the ,,united ,,states ,the storms of the ,united ,states follow1 however1 year after year1 a series of tracks1 not likely to change suddenly1 and not irregular1 but related to each other by very well-defined laws4 ,the ,united ,states ,weather ,bureau has made a very intensive study of the positions of the tracks of the storms4 ,fig4 #ee shows the mean tracks and the movement of storms from day to day4 ,this map indicates that generally there are two sets of lines running west and east1 one set over the northwestern boundary1 the ,lake region1 and the ,st4 ,lawrence ,valley1 the other set over the middle ,rocky ,mountain districts and the ,gulf ,states4 ,each of these is double1 with one for the 8highs0 and one for the 8lows40 ,furthermore1 there are lines crossing from the main tracks to join them together1 showing how storms pass from one to the other4 ,on the chart1 the heavy lines all belong to the tracks of the 8highs10 and the lighter lines to the track of the 8lows40 ,,the ,,mode ,,of ,,travel ,,of ,,the 8,,highs0 ,a 8high0 reaching the ,california coast may cross the mountains near ,salt ,lake ,city 7follow the track on the map71 and then pass directly over the belt of the ,gulf ,states1 turning northeastward and reaching the ,virginia coast2 or it may move farther northward1 cross the ,rocky ,mountains in the ,state of ,washington1 up the ,columbia ,river ,valley1 then turn east1 and finally reach the ,gulf of ,st4 ,lawrence4 ,these tracks are located where they are by the laws of general circulation of the atmosphere and the outline of the ,north ,american continent4 ,this movement of the 8highs0 from the middle ,pacific coast to ,florida or to the ,gulf of ,st4 ,lawrence is confined to the summer half of the year1 that is1 from ,april to ,september4 ,in the winter months1 on the other hand1 the source of the 8highs0 is different1 though they reach the same terminals4 ,,historical ,,facts ,,thermometers ,galileo discovered the principles of the thermometer in #aeib4 ,the ,grand ,duke of ,tuscany1 ,ferdinand ,,ii1 is given credit for perfecting it in #afaj4 ,athanasius ,kircher is given credit for the discovery of the mercurial thermometer4 ,this was about #afda4 ,ferdinand the ,,ii1 in #afej or thereabouts1 filled a glass tube with colored alcohol and hermetically sealed it after graduating the tube4 ,fahrenheit is given credit for the discovery that water freezes always at the same temperature4 ,with these facts he devised a scale for thermometers in #agad4 ,,thermometer ,,records ,a temperature of #aaa below zero has been recorded at an altitude of #dh1gjj feet in the ,united ,states4 ,the highest record in the ,united ,states ,weather ,bureau was taken in ,death ,valley1 ,cal41 on ,june #cj1 ,july #a and #b1 #ahia1 when the thermometer reached #abb ,f4 ,death ,valley is also given credit for the highest known monthly temperature1 which was #ajb ,f4 in the month of ,july4 ,arctic expeditions have records of #gc and #ff below zero4 ,this is the greatest natural cold recorded4 ,the average temperature in the ,united ,states is #eb4d2 the average temperature in ,england is #ej4 ,in the interior of ,australia a record has been taken of a drop of #fj to #gj in a few hours2 whereas the most rapid change recorded in the ,united ,states was #fj ,f4 in twenty-four hours4 ,this record has been made twice1 in #ahhj and again in #ahij4 ,the lowest temperature recorded in the ,united ,states ,weather ,bureau was at ,poplar ,river1 ,mont41 ,january1 #ahhe1 when the thermometer registered #fc below zero4 ,the estimated heat of the sun is #aj1jjj2 the highest artificial heat obtained is #g1jjj4 ,regarding the heat of the sun1 no definite conclusions have been arrived at1 so the above temperature is only approximate4 ,,regions ,,of ,,least ,,relative ,,humidity ,least relative humidity is found in places southwest of ,arizona1 where the average is about #dj4 ,fifty degrees humidity means half as much moisture as is necessary for complete saturation4 ,the average in other parts of the country is from #fj to #hj4 ,steel boils at #cejj2 water boils at #bab2 liquid air submitted to a degree of cold where it ceases to be a gas and becomes a solid is #cab below zero4 ,professor ,john ,dewar of ,england is credited with some of the most remarkable experiments with low temperature1 and at these temperatures made some wonderful discoveries4 ,he went down so cold that he could freeze liquid air back into a solid2 he continued further until he reduced hydrogen1 a very light gas1 to a liquid4 ,this was at #ddj below zero4 ,one of the most remarkable things he did was to freeze hydrogen into a solid4 ,water boils at #ahc4b ,fahrenheit on top of ,mt4 ,blanc2 water boils at #aid ,fahrenheit on top of ,mt4 ,quito4 ,,barometers ,torricelli is given credit for the discovery of the principles of the barometer4 ,otto ,von ,guericke1 of ,magdeburg1 to whom we are indebted for the air pump1 is credited as being the first person to use the barometer as a weather indicator4 ,because of the fact that the mercurial barometer is not adaptable for portability1 many scientists began work on producing a barometer without fluid that could be easily carried about and would give accurate results4 ,in #agih ,m4 ,comte1 professor of aerostatics in the school at ,meudon near ,paris1 invented the aneroid barometer1 which he used in his balloon ascents4 ,this instrument has been described fully on page #ee4 ,,barometer ,,records ,lowest reading taken in the ,united ,states by the ,united ,states ,weather ,bureau was #bh4dh1 or practically three quarters of a pound per square inch below normal4 ,altitude records have been taken with the barometer as high as #he1bgj feet4 ,this record was made at ,uccle ,observatory1 ,belgium1 the pressure being #j4fg at this point4 ,,hail ,hail varies from one-tenth inch to more than five inches in diameter4 ,the following is an extract from the 8,memoirs of ,benvenuto ,cellini0 of a terrible hail storm in ,lyons1 ,france1 in #aedd3 8,the hail at length rose to the size of lemons4 ,at about half a mile's distance all the trees were broken down1 and all the cattle were deprived of life2 we likewise found a great many shepherds killed1 and we saw hailstones which a man would have found it a difficult matter to have grasped in both hands40 ,new ,hampshire has the record for the largest hailstones seen here so far2 they were #d inches in diameter and weighed #ah ounces1 and were #ab inches in circumferences4 ,,rainfall ,there are records in ,japan of where rain has reached #cj inches in twenty-four hours2 in ,india where it has reached #dj inches in twenty-four hours4 ,the average rainfall in the ,united ,states is #ce inches4 ,there are certain places in ,india where the yearly rainfall averages over #dgj inches2 whereas other regions of ,india show less than #d inches4 ,the higher the clouds are in the air1 the larger the drops of rain when they reach the earth4 ,the heaviest annual rainfall recorded any place in the world is on the ,khasi ,hills in ,bengal1 where it registered #fjj inches4 ,the major part of this was in half of the year4 ,the greatest amount of rainfall is in the northwestern part of the ,united ,states2 the least amount is in ,arizona1 the southwestern part4 ,in some parts of ,egypt and ,arabia1 the only moisture that is received there is in the form of dew4 ,the average cloudiness of the earth has been estimated between #ej and #ee per cent4 ,this amount slightly exceeds the cloud conditions of the ,united ,states4 ,unalaska has a record of extreme cloudiness for one whole month1 ,february1 #ahhj4 ,sir ,j4 ,c4 ,ross1 an ,arctic explorer1 recorded a shower of nearly an hour's duration on ,christmas day1 #ahci1 without a cloud in sight4 ,a similar record was made on ,june #cj1 #ahgg1 at ,vevay1 ,ind41 where a shower lasted for five minutes in a cloudless sky4 ,a fall of yellow snow was recorded at ,south ,bethlehem1 ,pa41 in #ahhi4 ,examination showed this coloration to be due to the pollen of the pine trees which had been blown into the atmosphere before the fall4 ,another record of yellow rainfall was recorded at ,lynchburg on ,march #ba1 #ahgi4 ,golden snow was recorded at ,peckoloh1 ,germany1 in #ahgg4 ,green and red snows have been observed during ,arctic explorations1 due to a minute organism that was in the atmosphere4 ,when the temperature of the atmosphere is nearly #cb during a snow storm and the wind is blowing1 the flakes being damp and the snowfall heavy1 the flakes are apt to unite to form large masses of snow in the atmosphere or air1 which accounts for some of the following records3 ,at ,chapston1 ,wales1 in ,january1 #ahhh1 the snowflakes measured #c4f inches in length and #a4d inches in breadth1 and #a4c inches in thickness4 ,they amounted to #b cubic inches of water when melted4 ,there are some remarkable instances of where hailstones have cemented together1 making large masses of ice4 ,some remarkable records of this kind have been recorded in ,india4 ,in ,morganstown1 ,va41 on ,april #bh1 #ahgg1 hailstones #b inches long and #a inches in diameter fell4 ,the mean yearly pressure of the ,united ,states ranges between #cj and #cj4a inches when reduced by ordinary methods to sea level4 ,in ,unalaska1 ,january #ba1 #ahgi1 the barometer reading of #bg4gj inches was recorded1 and another low reading was made at ,stykkisholm of #bg4ia inches on ,february #a1 #ahgg4 ,on ,september #bg1 #ahhj1 a ship on the ,china ,sea experienced a terrific typhoon1 during which the barometer went down in four hours from #bi4fd to #bg4jd inches4 ,the greatest temperature ranges recorded are in the interior of ,siberia1 where at ,yakutsk they recorded a range of #aha4d4 ,the most remarkable changes recorded within twenty-four hours have been at ,fort ,maginnis1 ,mont41 ,january #f1 #ahhf1 a fall of #ef4dj2 at ,helena1 ,mont41 ,january #f1 #ahhf1 a fall of #ee in sixteen hours2 at ,florence1 ,ariz41 ,june #bf1 #ahha1 #fe rise4 ,on the northern edge of the ,african desert the temperature of the air rose to #abg4d4 ,the lowest single temperature in the world was recorded at ,werchojansk1 ,siberia1 in ,january1 #ahhe1 when it was #ij4d below zero1 while the average temperature for the month at the same place was #fc4i below zero4 ,highest mean rainfall occurs in ,sumatra1 averaging about #acj inches2 the rainfall of #dic4b inches per year occurs at ,cherapunji1 ,assam1 ,india1 which is the largest in the world4 ,the lowest rainfall in the world occurs at ,southeast ,california1 ,west ,arizona1 and the valley of lower ,colorado1 where the rainfall averages less than #c inches4 ,the most remarkable rainfall recorded in the ,united ,states for twenty-four hours occurred at ,alexandria1 ,la41 ,june #ae1 #ahhf1 when the rainfall reached the enormous amount of #ba4d inches4 ,the most remarkable rainfall recorded in the world occurred at ,purneah1 ,bengal1 ,september #ac1 #ahgi1 when the rainfall reached the unprecedented amount of #ce inches in twenty-four hours4 ,,cloudbursts ,on ,august #ag1 #ahgf1 at ,fort ,sully1 ,dakota1 occurred one of the heaviest cloudbursts ever known4 ,the water moved out of the canyon on the opposite side of the ,missouri in a solid bank three feet deep and #bjj feet wide4 ,there are many other remarkable cloudbursts recorded doing great injury1 drowning and killing many people4 ,,wind ,,velocity ,among the most remarkable wind velocity records is that of ,cape ,lookout on ,october #ag1 #ahgi1 when the wind blew at a rate of #ach miles an hour4 ,one of the worst cyclones ever recorded in ,north ,america was the flood1 as it is usually termed1 at ,galveston1 ,tex4 ,this storm began on the #ast day of ,september1 #aijj1 and lasted until the #abth4 ,it reached its maximum destructive force on the #hth4 ,six thousand lives were lost and #cj1jjj1jjj worth of property was destroyed4 ,even worse than any of these was the one at ,calcutta in #ahfd1 followed by a storm wave over #af feet high1 causing a death-rate of #de1jjj persons4 ,,blizzards ,the blizzard in ,dakota of #ahgc is one of the worst on record1 but probably the most disastrous in the ,united ,states occurred in ,montana1 ,dakota1 and ,texas on ,january #aa1 #ahhh4 ,the loss of life exceeded #ajj persons4 ,,tornadoes ,the ,united ,states is more liable to tornadoes than any other part of the globe4 ,in the ,united ,states over #c1jjj people have been killed by tornadoes and thousands more have been injured4 ,the greatest loss of lives recorded by tornadoes was at ,adams ,city1 ,miss41 on ,june #af1 #ahdb1 when #ejj lives were lost4 ,the most remarkable hail storm was that of ,july #ac1 #aghh1 through ,france to ,belgium1 and did a property damage of over five million dollars4 ,there have been many destructive hailstorms in the ,united ,states4 ,one on ,july #f1 #ahgh1 at central ,new ,york extended into parts of ,massachusetts1 ,rhode ,island and ,connecticut4 ,stones fell recorded to measure #g inches in diameter4 ,,rotary ,,motions ,,of ,,storms ,benjamin ,franklin has been given credit for the discovery that storms have a rotary motion1 and that they move from west to east4 ,this discovery was made in #agdg4 ,franklin did not positively prove these facts1 and it remained for ,redfield1 ,espy1 ,maury1 ,abbe to substantiate the truth of this statement4 ,,the ,,first ,,united ,,states ,,weather ,,bureau ,the first ,united ,states ,weather ,bureau was established in #ahgj4 ,general ,albert ,j4 ,myer was the first chief of the ,united ,states ,weather ,bureau4 ,it is estimated that we are #bej1jjj miles from the moon4 ,at high altitudes1 the cover of a kettle must be weighted down in order to boil an egg hard4 ,this is to enable the pressure of steam to allow temperature high enough for boiling4 ,in other words1 it would be impossible to boil an egg in an open vessel at a high altitude4 ---------------------------------------- -------------------------------- ,,memorandum ,illustration ,rain ,tomorrow6 ,you do not like your ball game or picnic postponed just because of rain1 do you8 ,you want a bright day for that event4 ,then don't guess what the weather will be on a certain day--know4 ,learn to use the ,gilbert ,weather ,bureau to read weather indications from instruments set up by yourself--in your own home4 ,this is an outfit you will like immensely4 ,made specially for your use and to provide you with a new kind of play4 ,the fun you get in making records of changes in temperature1 in humidity1 and in making forecasts will surely be great4 ,your boy friends will listen to you with interest when you explain to them the cause of storms and how important it is to have a knowledge of climatic disturbances4 ,the outfits contain all the necessary equipment and a big book on weather1 telling you how to know when it's going to storm and many other interesting things4 ,your dealer will show you the ,gilbert ,weather ,bureau ,sets4 ,if he hasn't them1 write ,,the ,a4 ,c4 ,,gilbert ,,company #ead ,blatchley ,avenue ,new ,haven1 ,conn4 ,in ,canada3 ,,the ,a4 ,c4 ,,gilbert-,,menzies ,,co41 ,limited1 ,toronto1 ,ont4 ,in ,england3 ,,the ,a4 ,c4 ,,gilbert ,,co41 #abe ,high ,holborn1 ,london ,w4,c4 #a ,illustration ,,what ,,is ,,sound8 ,do you know that hearing is just feeling with the ear8 ,that in reality1 the thing we call sound1 which we think of as a noise or as a musical note1 is just an impression on the brain8 ,very few boys know this1 and if you would like to be one of the few that do1 you surely want an outfit of ,gilbert ,sound ,experiments ,with one of these outfits you can find out just what sound is--how it is produced--why some pianos sound better than others--why a violin produces a musical tone1 and many other things1 including a number of startling table rapping tricks with which you can astonish your friends4 ,a big book of instructions tells you how to perform every experiment4 ,get one of these outfits today4 ,the best toy dealer in your town should have it2 if not1 write us and we'll tell you where you can get it4 ,,the ,a4 ,c4 ,,gilbert ,,company #ead ,,blatchley ,,ave4 ,,new ,,haven1 ,,conn4 ,in ,canada3 ,the ,a4 ,c4 ,gilbert-,menzies ,co41 ,limited1 ,toronto ,in ,england3 ,the ,a4 ,c4 ,gilbert ,co41 #abe ,high ,holborn1 ,london1 ,w4 ,c4 #b ,illustration ,in the ,dark6 ,a knock on the head with a hatchet or a stab with a knife doesn't sound pleasant1 but you'll enjoy apparent treatment of this kind and so will your friends who watch your shadow show4 ,make your boy friend rise in the air--change him into a bird or a cat--create freakish images4 ,it's easy6 ,and laugh--your audience sure will enjoy it because it's new--nothing like it4 ,an entertainment made for boys who want real fun4 ,but that's only a few of the many things you can do with ,,gilbert ,,light ,,experiments ,one of these outfits will help you to understand a great many facts about light4 ,you can perform a number of experiments which explain the laws of light4 ,learn about the movie machine1 the telescope and other optical instruments4 ,there's a big book on ,light with each set1 it's a handy size1 just right to put in your pocket4 ,from this book and your set you'll get a knowledge of light that will be helpful to you always4 ,it's great fun too1 the kind you like4 ,the outfit is complete with prisms1 mirrors and all the apparatus you'll need to perform the experiments4 ,ask your dealer to show you this new ,gilbert toy4 ,if he hasn't it write ,,the ,a4 ,c4 ,,gilbert ,,company #ead ,blatchley ,ave41 ,new ,haven1 ,conn4 ,in ,canada--,the ,a4 ,c4 ,gilbert-,menzies ,co41 ,limited1 ,toronto1 ,ont4 ,in ,england--,the ,a4 ,c4 ,gilbert ,co41 #abe ,high ,holborn1 ,london1 ,w4 ,c4 #a ,illustration3 ,,gilbert ,,boy ,,engineering ,the ,most ,helpful ,book for ,boys ,ever ,published ,illustration ,illustration ,think of it6 8,football ,strategy10 by ,walter ,camp--8,how to ,pole ,vault10 by ,former ,world's ,champion1 ,a4 ,c4 ,gilbert--8,flying10 by ,eddie ,rickenbacker1 and 8,athletic ,training10 by the famous ,yale trainer1 ,johnny ,mack4 ,chapters about signalling1 wireless1 wonderful heat1 sound and light experiments1 how to build a real weather bureau station of your own1 chemistry for boys1 electrical1 hydraulic and pneumatic engineering and surveying1 practical carpentry--all in one finely illustrated book4 ,it's yours for a quarter and worth dollars to you4 ,the ,greatest ,book for ,boys in ,years ,illustration ,buy it from your dealer1 or send us #be;c today4 ,you'll never be sorry ,the ,a4 ,c4 ,gilbert ,company #ead ,blatchley ,avenue ,new ,haven 3 ,conn4 ---------------------------------------- -------------------------------- ,,transcriber',s ,,notes #a4 ,p4 #fg1 changed 8it means that there is one one-hundredth of an inch of rain0 to 8it means that there is one one-tenth of an inch of rain04 ,makes the math consistent with the rest of the section4 #b4 ,p4 #fh1 changed 8by one hundred for actual rainfall0 to 8by ten for actual rainfall04 ,makes the math consistent with the rest of the section4 #c4 ,silently corrected obvious typographical errors and variations in spelling4 #d4 ,retained archaic1 non-standard1 and uncertain spellings as printed4 #e4 ,enclosed italics font in underscores4 #f4 ,enclosed bold font in equals4