,,united ,,states ,,department ,,of ,,agriculture ,,bulletin ,no4 #djd ,contribution from the ,bureau of ,plant ,industry ,,wm4 ,a4 ,,taylor1 ,chief ,illustration3 ,,usda crests flanking bulletin banner ,washington1 ,d4,c4 ,,professional ,,paper ,october #ad1 #aiaf ,,hemp ,,hurds ,,as ,,paper-,,making ,,material4 ,by ,,lyster ,h4 ,,dewey1 ,botanist in ,charge of ,fiber-,plant ,investigations1 and ,,jason ,l4 ,,merrill1 ,paper-,plant ,chemist1 ,paper-,plant ,investigations4 ,,contents4 ,page4 ,the production and handling of hemp hurds1 by ,lyster ,h4 ,dewey3 ,what hemp hurds are #a ,pith1 wood1 and fiber #b ,character of hurds affected by retting #b ,proportion of hurds to fiber and yield per acre #c ,hurds available from machine-broken hemp #c ,present uses of hemp hurds #d ,present supplies of hurds available #e ,baling for shipment #e ,cost of baling #e ,summary #f ,the manufacture of paper from hemp hurds1 by ,jason ,l4 ,merrill3 ,introduction #g ,factors justifying an investigation of hemp hurds #h ,character of the material #aa ,character of the tests #ab ,operations involved in a test #ac ,description of tests #af ,comparison of the tests and commercial practice #ba ,physical tests of the papers produced #bd ,conclusions #be ,in preparing the report on the manufacture of paper from hemp hurds it became evident that a short discussion of the agricultural aspects of this material should be included in the publication4 ,such an article was prepared1 therefore1 and the two reports are here presented together4 ,,note4--,this bulletin should be useful to all persons who are interested in the economic phases of paper making1 especially to print and book paper manufacturers4 ,it also should be of interest to scientific investigators and chemists4 ,,the ,,production ,,and ,,handling ,,of ,,hemp ,,hurds4 ,by ,,lyster ,h4 ,,dewey1 ,botanist in ,charge of ,fiber-,plant ,investigations4 ,,what ,,hemp ,,hurds ,,are4 ,the woody inner portion of the hemp stalk1 broken into pieces and separated from the fiber in the processes of breaking and scutching1 is called hemp hurds4 ,these hurds correspond to shives in flax1 but are much coarser and are usually softer in texture4 ,the hemp stalk grown in a broadcast crop for fiber production is from one-eighth to three-eighths of an inch in diameter and from #d to #aj feet tall4 ,the stalk is hollow1 with a cylindrical woody shell1 thick near the base1 where the stalk is nearly solid1 and thinner above1 where the hollow is relatively wider4 ,in the process of breaking1 the woody cylinder inside of the fiber-bearing bark is broken into pieces one-half of an inch to #c inches long and usually split into numerous segments4 ,the thicker lower sections are split less than the thin-shelled upper ones1 and they are often left quite solid4 ,,pith1 ,,wood1 ,,and ,,fiber4 ,the inner surface of the hurds usually bears a layer of pith1 consisting of thin-walled cells nearly spherical or angular1 but not elongated4 ,they are more or less crushed and torn4 ,they are probably of little value for paper1 but they constitute less than #a per cent of the weight of the hurds4 ,the principal weight and bulk consist of slender elongated woody cells4 ,the outer surface is covered with fine secondary fibers composed of slender elongated cells1 tougher than those of the wood but finer and shorter than those of the hemp fiber of commerce4 ,no method has been devised thus far which completely separates from the hurds all of the long fiber4 ,from #e to #ae per cent of the weight of the hurds consists of hemp fiber1 in strands from #c inches to #h feet in length4 ,some fragments of the bark1 made up of short cubical cells1 usually dark in color1 cling to the strands of fiber4 ,,character ,,of ,,hurds ,,affected ,,by ,,retting4 ,nearly all of the hemp in the ,united ,states is dew retted4 ,the stalks are spread on the ground in swaths as grain is laid by the cradle4 ,the action of the weather1 dew1 and rain1 aided by bacteria1 dissolves and washes out the green coloring matter 7chlorophyll7 and most of the gums1 leaving only the fibrous bark and the wood4 ,the plants in this process lose about #fj per cent of their green weight1 or about #dj per cent of their air-dry weight4 ,the stalks are sometimes set up in shocks to cure before retting1 and after retting they are set up in shocks to dry4 ,each time the stalks are handled they are chucked down on the ground to keep the butts even4 ,in these operations sand and clay are often driven up into the hollow at the base of the stalks1 and this dirt1 which often clings tenaciously1 may constitute all objectionable feature in the use of hemp hurds for paper stock4 ,in ,italy and in most localities in ,russia and ,austria-,hungary where hemp is extensively cultivated1 it is retted in water1 but water retting has never been practiced in the ,united ,states except to a limited extent before the middle of the last century4 ,hurds from water-retted hemp are cleaner and softer than those from dew-retted hemp4 ,the fiber is sometimes broken from dry hemp stalks without retting4 ,the hurds thus produced contain a small percentage of soluble gums1 chiefly of the pectose series4 ,comparatively little hemp is prepared in this manner in ,america4 ,process retting by means of weak solutions of chemicals or oils in hot water is practiced to a limited extent4 ,the hurds from these processes may contain traces of the chemicals or oils and also soluble gums in greater degree than those of the dew-retted or water-retted hemp4 ,,proportion ,,of ,,hurds ,,to ,,fiber ,,and ,,yield ,,per ,,acre4 ,illustration3 ,,fig4 #a4--;,hemp-breaking machine4 ,the stalks are fed sidewise in a continuous layer #b to #c inches thick1 turning out about #d1jjj pounds of clean fiber per day and five times as much hurds4 ,the yield of hemp fiber varies from #djj to #b1ejj pounds per acre1 averaging #a1jjj pounds under favorable conditions4 ,the weight of hurds is about five times that of the fiber1 or somewhat greater from hemp grown on peaty soils4 ,a yield of #b-a_/b tons of hurds per acre may be taken as a fair average4 ,,hurds ,,available ,,from ,,machine-,,broken ,,hemp4 ,hemp hurds are available only from hemp which is broken by machines1 when the hurds may be collected in quantity in one place 7figs4 #a and #b74 ,most of the hemp in ,kentucky is still broken by hand brakes4 ,these small brakes are moved from shock to shock1 so that the hurds are scattered all over the field in small piles of less than #ej pounds each1 and it is the common practice to set fire to them as soon as the brake is moved4 ,it would be difficult to collect them at a cost which would permit their use for paper stock4 ,where machine brakes are used1 the hemp stalks are brought to the machine as grain is brought to a thrashing machine1 and the hurds accumulate in large piles1 being blown from the machine by wind stackers4 ,machine brakes are used in ,wisconsin1 ,indiana1 ,ohio1 and ,california1 but to only a limited extent in ,kentucky4 ,five different kinds of machine brakes are now in actual use in this country1 and still others are used in ,europe4 ,all of the best hemp in ,italy1 commanding the highest market price paid for any hemp1 is broken by machines4 ,the better machine brakes now in use in this country prepare the fiber better and much more rapidly than the hand brakes1 and they will undoubtedly be used in all localities where hemp raising is introduced as a new industry4 ,they may also be used in ,kentucky when their cost is reduced to more reasonable rates1 so that they may compete with the hand brake4 ,hemp-breaking machines are being improved and their use is increasing4 ,the hemp-growing industry can increase in this country only as machine brakes are developed to prepare the fiber4 ,a profitable use for the hurds will add an incentive to the use of the machine brake4 ,illustration3 ,,fig4 #b4--,machine brake and hemp hurds4 ,hemp hurds from machine brakes quickly accumulate in large piles4 ,,present ,,uses ,,of ,,hemp ,,hurds4 ,hemp hurds are used to a limited extent for barnyard litter and stable bedding1 as a substitute for sawdust in packing ice1 and1 in rare instances1 for fuel4 ,they are not regarded as having a commercial value for any of these uses1 though they are doubtless worth at least #a per ton on the farm when used for stable bedding4 ,they are a waste product1 without value for other purposes which might compete with their use for paper stock4 ,,present ,,supplies ,,of ,,hurds ,,available4 ,during the last season1 #aiae1 about #a1ejj acres of hemp have been harvested outside of ,kentucky and in regions where machine brakes are used4 ,estimating the yield of hurds at #b-a_/b tons per acre1 this should give a total quantity of about #c1gej tons4 ,large quantities of hemp from the crop of #aiad1 which are still unbroken in these areas1 and large piles of hurds undisturbed where the machines have been used during the last two or three years1 increase the total to more than #g1jjj tons4 ,hemp is now grown outside of ,kentucky in the vicinity of ,mc,guffey1 east of ,lima1 ,ohio2 around ,nappanee1 ,elkhart ,county1 and near ,pierceton1 in ,kosciusko ,county1 ,ind42 about ,waupun and ,brandon1 ,wis42 and at ,rio ,vista and ,stockton1 ,cal4 ,in ,kentucky1 hemp is grown in most of the counties within a radius of #ej miles of ,lexington4 ,no accurate statistics of the acreage are collected1 but the crop harvested in #aiae is estimated at #g1jjj acres4 ,a machine brake will probably be used in ,bourbon ,county and also in ,clark ,county1 but most of the hemp in ,kentucky will be broken on hand brakes4 ,,baling ,,for ,,shipment4 ,the hurds will have to be baled to facilitate handling in transportation and to economize storage space at the paper mills4 ,the bales will need to be covered with burlap or some material to keep them from shaking out4 ,they may be baled in the same presses that are used for baling hemp fiber1 but care must be exercised to avoid breaking the press1 for the hurds are more resistant than hemp fiber4 ,a bale of hemp #b by #c by #d feet weighs about #ejj pounds4 ,a bale of hurds of the same size will weigh about one-third less1 or approximately six bales per ton4 ,rough hemp fiber as it is shipped from the farm is not covered2 therefore1 the covering material must be purchased especially for the hurds4 ,a piece of burlap about #cf by #dh inches placed on either side of the bale will be sufficient1 but these pieces1 weighing about #c pounds each1 cost about #dj cents a pair4 ,baling rope1 in addition to jute covering1 will cost at least #e cents per bale1 making the total cost of covering and ties #b4gj or more per ton4 ,possibly chip-board1 costing about #cc per ton1 or not more than #e cents for the two pieces for each bale1 may be used in place of burlap4 ,chip-board1 burlap1 and also rope ties may all be used for paper stock4 ,burlap covers might be returned1 to be used repeatedly until worn out1 but chip-board could not be used more than once4 ,,cost ,,of ,,baling4 ,if burlap covers are used the cost of baling1 including covering1 ties1 use of baling press1 power1 and labor will amount to at least #fj cents per bale1 or about #c4ge per ton4 ,if chip-board can be used the cost may be reduced to about #b per ton4 ,the cost of hauling and loading on the cars will vary from #a to #c per ton1 depending upon the distance and the roads4 ,the farmer must therefore receive from #d to #f per ton for the hurds1 baled1 on board cars at his home station4 ,,summary4 ,hemp hurds are the woody inner portion of the hemp stalk1 broken into pieces in removing the fiber4 ,they are not used at present for any purpose that would compete with their use for paper4 ,hurds are available only from machine-broken hemp1 for the cost of collecting them from the hand brakes would be too great4 ,about #g1jjj tons are now available in restricted localities in ,ohio1 ,indiana1 ,wisconsin1 and ,california4 ,the quantity is likely to increase as the use of machine brakes increases4 ,the hurds may be baled in hemp-fiber presses1 with partial burlap covers like those on cotton bales1 or possibly chip-board covers4 ,it is estimated that the farmers may deliver the bales on board cars profitably at #d to #f per ton4 ,,the ,,manufacture ,,of ,,paper ,,from ,,hemp ,,hurds4 ,by ,,jason ,l4 ,,merrill1 ,paper-,plant ,chemist1 ,paper-,plant ,investigations4 ,,introduction4 ,the purpose of this paper is to report upon preliminary tests which were conducted to determine the paper-making value of hemp hurds1 a crop waste of the hemp-fiber industry4 ,the search for plant materials capable of being utilized in paper manufacture is a comparatively recent but world-wide activity which has for its object the husbanding of present sources of paper-stock supply by the substitution of new materials for some of those which are rapidly becoming less plentiful and more costly4 ,the abstract idea of utilizing that which is at present a waste can play no important rle in such activities1 the successful commercial outcome of which must be based on the three fundamental factors--market or demand for product1 satisfactory raw material1 and cost4 ,since hemp hurds are to be treated in this report as a raw material for the manufacture of book and printing papers1 the qualities1 supply1 probable future1 and cost of the material will be considered in comparison with wood1 with which it must compete4 ,there seems to be little doubt that the present wood supply can not withstand indefinitely the demands placed upon it1 and with increased scarcity economy in the use of wood will become imperative4 ,this effect is already apparent in many wood-using industries1 and although the paper industry consumes only about #c per cent of the total forest cut1 it is probable that it will be affected through this economy4 ,our forests are being cut three times as fast as they grow1 and as wood becomes more expensive proper growing and reforesting will receive more attention4 ,thus1 naturally1 a balance will be established between production and consumption1 but as this condition approaches its limiting values the price of wood may rise to such levels that there will be a demand for other raw materials4 ,the use of waste paper in conjunction with chemical wood pulp has increased to enormous proportions1 and it is probable that the increase will continue4 ,although it is a cheaper raw material than wood1 it is reasonable to suppose that as the wood supply decreases and the price of wood pulp advances1 the price of waste paper will advance somewhat proportionately4 ,in view of these conditions it is advisable to investigate the paper-making value of the more promising plant materials before a critical situation arises4 ,to be of substantial value the investigations should include not only a determination of the quality and quantity of pulp and paper which the material is capable of producing1 but should embrace a consideration of such relevant factors as agricultural conditions1 farm practice1 assembling conditions1 transportation1 and probable future supply4 ,certain cultivated plants seem particularly promising1 because in the harvesting of the regular crop that portion which might be utilized for paper manufacture necessarily is either wholly or partially assembled4 ,to this class of plants belong corn1 broom corn1 sorghum1 sugar cane1 bagasse1 flax1 hemp1 and the cereal straws4#a ,footnote #a3 ,for descriptions of investigations of some of these crops1 see the list of publications at the end of this bulletin4 ,it is generally conceded that the employment of different raw materials would probably yield products of a somewhat different quality than those now prevailing in the markets1 but the qualities of papers and the public demands are so diversified and numerous that this possible objection should not be serious4 ,ten years ago sulphite manufacturers would not accept consignments of spruce logs if they contained over #e per cent of fir1 while to-day many manufacturers tolerate #ej per cent4 ,rope papers are found to contain not only jute1 but when this raw material is not plentiful1 chemical pulp of various kinds4 ,linen paper is often no more than a trade term4 ,not long ago printing papers were made entirely from chemical wood pulp1 but to-day if it is desired to secure paper which is free from ground wood the specifications must so stipulate4 ,writing papers1 formerly made entirely from rags1 now are likely to contain either chemical or even ground-wood pulp unless the specifications prohibit it4 ,without doubt1 many paper manufacturers have maintained certain papers up to a fixed standard for a long series of years1 but it is equally true that competition has lowered the standard of a great many papers1 some of which had acquired a distinctive recognition4 ,the employment of plant fibers will not necessarily lower the present quality of papers1 but if their employment does result in products whose qualities are somewhat different from our so-called standard papers it does not necessarily follow that such papers will not find a ready market4 ,,factors ,,justifying ,,an ,,investigation ,,of ,,hemp ,,hurds4 ,hemp hurds form a crop waste1 in that they necessarily are produced in the raising and preparation of hemp fiber1 and their present use and value are comparatively insignificant4 ,the assembling of the hurds may be effected with economy1 since the area in which hemp is handled with the use of machine brakes is restricted4 ,although it must be stated that the present annual supply would not be sufficient to justify the installation of a pulp mill nor would its transportation to existing mills appear feasible1 it is expected that the available annual tonnage1 especially in certain general sections1 will increase1 due to the increased use of the machine brake4 ,the present tonnage per annum is approximately as follows3 ,in the region of ,ohio and ,indiana1 #b1ejj tons2 in the ,wisconsin section1 #a1jjj tons2 in the ,california region1 #a1djj tons4 ,in years of adverse weather conditions there are often large areas of hemp which are not harvested on account of its poor quality2 there are also large areas of cut hemp which become overretted1 due to inclement weather4 ,it has been suggested by some of the hemp raisers that this large amount of material might be utilized as a paper stock4 ,in these cases the cost of the whole material would probably be somewhat higher than that of the hurds1 because either all or part of the cost of harvesting and the total cost of breaking would have to be borne by the paper maker4 ,moreover1 the quality of this material would be so very irregular and the supply so uncertain that it probably would not appeal to the paper manufacturer4 ,without doubt1 hemp will continue to be one of the staple agricultural crops of the ,united ,states4 ,the wholesale destruction of the supply by fire1 as frequently happens in the case of wood1 is precluded by the very nature of the hemp-raising industry4 ,since only one year's growth can be harvested annually the supply is not endangered by the pernicious practice of overcropping1 which has contributed so much to the present high and increasing cost of pulp wood4 ,the permanency of the supply of hemp hurds thus seems assured4 ,the favorable location geographically of the hemp regions in relation to the pulp and paper industry is a factor of considerable importance4 ,the ,kentucky region is not at present in a position to supply hurds1 as machine methods have not been adopted there to any appreciable degree4 ,the ,ohio and ,indiana region1 which at present has the greatest annual tonnage1 with the prospect of an increase1 is situated south of the ,wisconsin and ,michigan wood-pulp producing region and at a distance from the eastern wood-pulp producing regions2 therefore1 it is in a favorable position to compete in the large ,ohio and ,indiana markets4 ,since1 as will be shown1 the hurd pulp acts far more like soda poplar stock than sulphite stock1 competition would be strongest from the eastern mills2 in fact1 the hurd stock might very possibly meet with favor as a book-stock furnish in the ,michigan and ,wisconsin paper mills1 which are within the sulphite fiber-producing region4 ,because of its very close proximity to paper mills1 this latter possibility applies with far greater force to the ,wisconsin hemp region1 where a considerable extension of the hemp industry is anticipated4 ,illustration3 ,,fig4 #c4--;,a representative sample of hemp hurds1 natural size1 showing hemp fiber and pieces of wood tissue4 ,,character ,,of ,,the ,,material4 ,as received from ,pierceton1 ,ind41 the hurds consisted of a mixture of tangled hemp bast fibers and pieces of broken wood of the hemp stalk4 7,fig4 #c47 ,no reliable data were secured as to the proportion of bast fiber in the total shipment of #d tons1 although two hand separations of small representative samples gave results averaging #h per cent4 ,the chemical character of the material was such and the quantity was so small that any appreciable variation of the proportion should not affect materially the treating processes finally adopted1 yet its presence in varying proportions undoubtedly would modify to some extent the quality of the resulting paper product4 ,since the length of the ultimate bast fiber averages about #bb mm4 and the length of the ultimate hemp wood fiber averages #j4g mm41 it is natural to assume that the bast fiber would tend to increase the strength of paper produced from the hurds4 7,fig4 #d47 ,illustration3 ,,fig4 #d4--;,fiber derived from the woody portion of the hurds4 #ge4 ,from a microphotograph4 ,the broken pieces of wood contained in the hurds varied in length from mere particles which were somewhat finer than sawdust to pieces about #c-a_/b inches long1 exceptional pieces being found which measured #f inches in length4 ,the majority of the long pieces were between #b and #c inches in length4 ,in thickness the pieces ranged from one-eighth of an inch1 in case they were derived from the base of the hemp stalks1 to about one sixty-fourth of an inch in those pieces which were derived from the top and branches of the stalks4 ,in cross section the pieces often were found to be a quarter or half of the rounded rectangular woody shell of the stalk1 although there appeared to be no regularity in this respect4 ,from the pulp-maker's standpoint the great irregularity in thickness1 length1 and mass of the woody pieces militates decidedly against economy in pulp production4 ,the smaller pieces reduce by chemical treatment sooner than the larger fragments and are thereby overtreated1 which results in a lower yield of cellulose fiber and a product composed of undertreated and overtreated fibers1 the production and use of which are not satisfactory or economical4 ,it probably would be found more satisfactory1 therefore1 to screen or sort the hurds and treat the various sizes separately and differently4 ,associated with the hurds was a small quantity of chaff and dirt1 composed chiefly of sand1 soil1 particles of hemp leaves and flowers1 and other extraneous matter4 ,the sand and soil were present because of the practice of placing the stalks in shocks in the field1 the butts of the stalks being in contact with the soil4 ,it is a simple matter1 however1 to remove the chaff and dirt by sieving1 and this practice was followed in most of the paper tests conducted with this material4 ,,character ,,of ,,the ,,tests4 ,because of the similarity of hemp hurds to other materials which have been tested by the ,office of ,paper-,plant ,investigations1 semicommercial tests were conducted in cooperation with a paper manufacturer without preliminary laboratory tests4 ,laboratory pulp and paper tests are regarded only as a preliminary to semicommercial tests and therefore are not employed unless the material in question presents new features which should receive investigation before larger sized tests are undertaken4 ,the advantages of cooperative mill tests are many1 among which may be mentioned the counsel and advice of the mill management and employees1 the services of specialized and skilled labor1 facilities for comparing the processes and the results of tests with commercial processes and results1 and the use of commercial or semicommercial types and sizes of machinery4 ,tests conducted in this manner and on this scale are of a different quality than is possible in those conducted in a laboratory1 and the results are susceptible of commercial interpretation with a fair degree of reliability4 ,it is found1 in general1 that the cost of securing such equipment and service for a complete and comprehensive test does not exceed #ejj1 while the installation of an equally satisfactory equipment alone would cost at least #ej1jjj and in many cases very much more4 ,tests conducted in this manner constitute a direct demonstration to the manufacturer1 and the results obtained are found to carry more weight when presented to other manufacturers for consideration4 ,it is well known that the method of conducting tests necessarily varies with the size of the test4 ,in the matter of yield determination1 for example1 laboratory tests may be on such a small scale that the weighing and sampling of the resulting cellulose fibers may be conducted by means of chemical laboratory apparatus and analytical balance1 while in tests involving a matter of #e to #aj pounds of material larger and different types of equipment are necessary4 ,when the tests are so increased in size as to employ #cjj or #djj pounds1 still other types of equipment are necessary for the treatment of the material and for a determination of the yield of fiber4 ,in tests involving tons of material the equipment involves the use of machines4 ,accuracy in degree of control and in results will vary materially with the size of the test4 ,as the size of the test increases1 certain factors will vary in a beneficial manner1 while others will vary in a detrimental manner1 so it is a question for each investigator to decide1 after taking all factors into consideration1 as to the size of test which will give the most satisfactory results4 ,in work of this nature it is found1 on the whole1 that better results are obtained in large tests1 although the control of the factors and the determination of the yield of fiber are more difficult than in smaller tests4 ,in the tests described in this bulletin1 the ,department of ,agriculture employed a rotary digester of its own design1#b comprising a shell #e feet #e inches in length by #d feet in diameter1 capable of holding about #cjj pounds of air-dry hurds4 ,it is believed that a test of this size is large enough to give satisfactory results and that the results are susceptible of commercial interpretation1 while at the same time they are sufficiently small for complete control and to afford fiber-yield figures which are both accurate and reliable4 ,two such rotary charges gave enough fiber for one complete paper-making test4 ,footnote #b3 ,for a description of this rotary digester1 see ,brand1 ,c4 ,j41 and ,merrill1 ,j4 ,l41 ,zacaton as a paper-making material1 ,u4 ,s4 ,dept4 ,agr4 ,bul4 #cji1 p4 #bh1 #aiae4 ,,operations ,,involved ,,in ,a ,,test4 ,a complete test on hurds comprises seven distinct operations1 and the method will be described1 operation by operation1 in the order in which they were conducted4 ,sieving4--,the hurds for the first test were not sieved to remove sand and dirt1 but the resulting paper was so dirty that sieving was practiced in all subsequent tests4 ,the hurds were raked along a horizontal galvanized-iron screen1 #ae feet long and #c feet wide1 with #aa-a_/b meshes per linear inch1 the screen being agitated by hand from below4 ,various amounts of dirt and chaff could be removed1 depending on the degree of action1 but it was found that if much more than #c per cent of the material was removed it consisted chiefly of fine pieces of wood with practically no additional sand or dirt2 in most of the tests1 therefore1 the material was screened so as to remove approximately #c per cent4 ,it became apparent that a finer screen would probably serve as well and effect a saving of small but good hurds4 ,cooking4--,cooking is the technical term for the operation by which fibrous raw materials are reduced to a residue of cellulose pulp by means of chemical treatment4 ,in these tests about #cjj pounds of hurds were charged into the rotary with the addition of a caustic-soda solution1 such as is regularly employed in pulp mills and which tested an average of #aji4e grams of caustic soda per liter1 or #j4iaf pound per gallon1 and averaged #he per cent causticity4 ,sufficient caustic solution was added to furnish #be or #cj per cent of actual caustic soda1 calculated on the bone-dry weight of hurds in the charge4 ,after closing the rotary head1 it was started rotating at the rate of one-half revolution per minute1 and in about five minutes steam at #abj pounds per square inch was admitted at such a rate that the charge was heated in one hour to #agj ,c41 which is the theoretical equivalent of #ajj pounds of steam pressure per square inch4 ,it was found1 however1 that when the temperature reached #agj ,c4 the pressure was usually #aae or #abj pounds instead of #ajj pounds1 due to air and gases inclosed in the rotary4 ,at this point the rotary was stopped and steam and air relieved until the pressure dropped to #ajj pounds1 or a solid steam pressure4 ,the temperature was maintained at this point for the number of hours required to reduce the hurds1 which was found to be about five1 after which the rotary was stopped and steam relieved until the pressure was reduced to zero1 when the head was removed and the stock was emptied into a tank underneath1 measuring #e-a_/b by #f by #b feet deep1 where it was drained and washed4 ,samples of waste soda solution or black liquor1 which were taken from some of the cooks for analysis1 were drawn while the stock was being thus emptied into the drainer4 ,determination of yield4--,for determining the yield of cellulose fiber the stock in the drain tank was washed with water until free from waste soda solution1 when1 by means of a vacuum pump communicating with the space between the bottom and the false perforated bottom1 the water was sucked from the stock1 leaving the fiber with a very uniform moisture content throughout its entire mass and in a condition suitable for removing1 sampling1 and weighing for a yield determination4 ,tests have shown that it is possible to sample and calculate the yield of bone-dry fiber within #j4je per cent of the actual amount4 ,it has been found that stocks from different materials vary greatly in their ability to mat in the drain tank1 thereby enabling a good vacuum to be obtained1 some stocks permitting a #be-;inch vacuum to be obtained1 while others will not permit more than #e inches4 ,for this reason the moisture content of the stock will vary from #fe to #he per cent4 ,washing and bleaching4--,washing and bleaching were performed for the purpose of bleaching the brown-colored cooked stock to a white product1 since it was regarded as highly probable that the fiber would be suitable for book-paper manufacture4 ,the colored stock was charged into a #djj-pound beating and washing engine of regular construction and washed about one hour1 the cylinder washer being covered with #fj-mesh wire cloth in order to remove fine loose dirt and chemical residues4 ,the washer was then raised1 the stock heated by steam to about #dj ,c41 and a solution of commercial bleaching powder was added in the quantity judged to be necessary1 after which the stock was pumped to a large wooden tank1 to remain and bleach over night4 ,if the stock was bleached sufficiently white it was drained and washed from bleach residues1 and if not more bleach was added until a good color was obtained4 ,the bleaching powder used was estimated to contain #ce per cent of available chlorin1 as this is the commercial practice1 and the amount required was calculated to the bone-dry weight of the unbleached stock4 ,more bleach is required for undercooked stock than for stock which is properly cooked or overcooked2 therefore1 the percentage of bleach required is an indication of the quality of the cooked stock4 ,since bleaching is usually more expensive than cooking1 it is desirable to cook to such a degree that the consumption of bleach will be held within certain limits1 depending on the raw materials used and the quality of paper to be produced4 ,in these tests it was desirable so to cook the hurds that the consumption of bleach would not be over about #aj per cent of the fiber4 ,furnishing4--,furnishing is the operation of charging the beating engine with the desired kind or kinds of fiber in the proper proportion and amount and the adding of such loading and sizing agents as may be necessary4 ,as shown in the record of results1 the furnish in these tests consisted of hurd stock alone and of various proportions of hurds1 sulphite fiber1 and soda fiber4 ,the percentages to be given in the record of the furnishes refer to the percentage of the total fiber furnish1 and this likewise applies to the loading and sizing agents4 ,in case sulphite or soda fiber was used1 the commercial product in the dry state was charged into the beating engine and disintegrated1 after which the hurd stock was added in the wet condition4 ,beating4--,beating is that operation concerning which the paper makers often say there is where the paper is really made1 and although the statement may not be literally true it contains a great deal of truth4 ,it is the operation whereby the fibers are separated from each other1 reduced to the proper lengths1 and put in such a physical or chemical condition that they felt properly and form into a satisfactory sheet4 ,it is probable that the quality of the sheet depends more upon the proper beater action than upon any other single operation4 ,the action consists in drawing a water suspension of the fiber between two sets of rather blunt knives1 one set being located in the bottom of a circulating trough and the other set on the periphery of a roll revolving just above the former set of knives4 ,it is during this operation that the loading and sizing agents are incorporated and the whole furnish is tinted either to produce a satisfactory white or the desired color4 ,the term paper making1 as used in this publication1 means the operation of forming the finished sheet of paper from stock which has been furnished and prepared in the beater4 ,in these tests a #cj-;inch ,fourdrinier machine of regular construction was used1 a machine which often is used for the production of paper for filling regular commercial orders4 ,the machine is designed to cause the water suspension of fibers to flow on to a traveling wire cloth1 whereby the water drains away4 ,more water is removed by passing the wet sheet through a series of press rolls1 after which the sheet is dried on steam-heated drums and passed through polished iron rolls1 which impart a finish to the sheet4 ,a ,jordan refining machine was employed in conjunction with the machine to improve further the quality of the fiber1 and a pulp screen was used in order to remove coarse and extraneous materials from the fiber4 ,,description ,,of ,,tests4 ,the nature of each complete paper test and the dependence of each operation on the others were such that it does not seem advisable to submit the results of the seven tests in tabular form4 ,the numerous cooks1 however1 which furnished the pulp for the paper tests are presented in ,table ,i in all essential detail4 ,,table ,i4--,data on cooking hemp hurds4 ---------------------------------------- ------------------------------ ,cooking ,yield of ,caustic ,strength of bone-dry soda used caustic soda,causticity------------------- fiber ,cook 7percentage 7grams per of soda 7percentage ,no4 of bone-dry liter74 solution4 ,time ,temperatureof bone-dry hurds74 7hours74 7,c47 unsieved hurds74 ---------------------------------------- ----------------------------- #bic #bj4f #ajj #ge4c #c #aff #bid #ba #ajj #ge4c #c #aff #bie #ba4f #ajj #ge4c #c #aff #bif #bj4c #ajj #ge4c #c #aff #cja #ba4i #ajj #hb4e #d #aff #c #cjb #bd4d #ajj #hb4e #d #aff #cjc #bd4b #ajj #hd4c #d #aff #dd4a #cjd #be #ajj #hd4c #d #agj #ci4e #cje #be #ajj #hd4c #e #agj #ci4d #cjf #bg4h #ajg4e #hd4c #d #aff #cf4e #cjg #bf4g #ajg #hd4d #e #agj #ch4a #cjh #bf #ajg #hd4d #e #agj #cg4c #cji #bg4c #ajg #hd4d #e #agj_/ #caj #bg4a #ajg #hd4d #f #agj #cg4j #caa #bg4b #ajg #hd4d #f #agj #cf4h #cab #bh4c #aaf4e #he4e #e #agj #ce4i #cac #bi4a #aac4a #hd4i #e #agj #ce4b #cad #bi4a #aji #hc4i #e #agj_/ #cae #bi4d #aji #hc4i #e #agj #cd4i #caf #cj #aji4e #hd4i #e #agj #cg4b #cag #bi4f #aji4e #hd4i #e #agj #cg4j #cah #bi4f #ajg #hd4h #e #agj #cg4g #cai #bi4d #ajg4e #hd4b #e #agj #ce4d #cbj #bi4c #ajg4e #hd4b #e #agj_/ ---------------------------------------- ----------------------------- ,footnote #c3 ,stock not used2 dirty4 ,discussion of the various cooks will be given in connection with the descriptions of those paper tests in which the stocks from the cooks were used1 since a stock and its cooking condition can be judged adequately only after it has been put through the various processes and into the finished sheet of paper4 ,the first test consisted in making four separate cooks1 ,nos4 #bic1 #bid1 #bie1 and #bif1 of approximately #cjj pounds each1 dividing the total stock into two parts and making two separate paper tests4 ,the first test was made primarily in order to learn some of the qualities and characteristics of the stock and to get the machinery equipment adjusted properly4 ,the yield of fiber was not determined in this preliminary test1 since the knowledge of it was not essential at this stage of the work4 ,the cooked stock which was emptied into the drainer to be washed free from black liquor was composed largely of whole pieces of hurds1 but only slight pressure between the fingers was required to crush the pieces4 ,in the case of wood1 this condition ordinarily would indicate undercooking1 but might not in the case of hurds4 ,further observation on the action of the cooked stock during subsequent processes was necessary in order to judge of its quality or the suitability of the cooking conditions4 ,the total cooked stock1 about #ejj pounds1 was divided into two portions of #bjj and #cjj pounds1 respectively1 and work was continued on them separately4 ,the #bjj-pound test1 designated as run ,no4 #ace1 was put into a #cej-pound washing engine1 washed one hour1 and given a total light brush of #b-a_/d hours4 ,the washing removed a great amount of dirt1 but the engine did not reduce the hurd stock as much as was desired4 ,after heating the stock in the beater to #dj ,c41 it was bleached with bleaching-powder solution1 #id gallons at #j4dah pound bleach per gallon1 equivalent to #ai4g per cent of the fiber4 ,this percentage of bleach is regarded as too high for stock intended for book-paper manufacture1 and subsequent cooks therefore were given harder treatment in order to reduce this figure4 ,after draining and washing free from bleach residues1 the stock was furnished in the beater with #ac per cent of clay1 #a per cent of resin size1 and #b4e per cent of alum1 was tinted blue1 given one hour's light brush1 and pumped to the stock chest4 ,when running it on the paper machine1 the ,jordan refiner seemed to have little effect in reducing shives of undertreated wood1 which indicated further the necessity of harder cooking4 ,the furnish acted well on the paper machine at #gj feet per minute1 but appeared somewhat too free on the wire4 ,the paper produced from this test is of very low quality1 due to the improper preparation of the stock1 lack of sufficient bleach1 the use of too small an amount of blue tinting1 and the presence of an excessive amount of dirt1 sand1 and shives4 ,the excessive amount of dirt and sand suggested the sieving of the hurds before cooking1 and this was performed in all subsequent cooks4 ,the finish of the sheet is very poor1 due to the fact that the calender stack was composed of very light rolls which did not have a satisfactory surface1 yet the stack is known to be able to produce better finishes if the proper stock is employed4 ,run ,no4 #acf was made on the #cjj-pound portion of stock from cooks ,nos4 #bic1 #bid1 #bie1 and #bif1 and in essentially the same manner as run ,no4 #ace4 ,the stock was washed one hour1 but given a brush of three hours1 and this brush was harder than in run ,no4 #ace4 ,bleach to the extent of #ai4h per cent of the fiber was used1 assisted by #a pint of oil of vitriol1 and the resulting color was an improvement over that of run ,no4 #ace4 ,after adding #ac4e per cent of clay and sizing with #a4a per cent of resin size1 the furnish was given one-half hour's light brush1 tinted1 and run on the machine1 which was set at #gj feet per minute4 ,this stock acted better on the wire and gave no trouble on the machine1 but it still seemed to be impossible to reduce the wood shives by manipulation of the ,jordan refiner4 ,the resulting sheet is an improvement over that produced by ,no4 #ace1 but is far from satisfactory4 ,run ,no4 #ach was made from hurds which1 as in all subsequent tests1 were sieved on a #aa-a_/b-mesh wire screen until practically all the loose dirt and sand was removed1 which operation caused a loss averaging #c per cent of the hurds4 ,stock from cooks ,nos4 #cjb and #cjc was used for this run and the increased amount of caustic soda and the increase in the time of cooking gave a stock of better appearance than those of preceding tests4 ,the stock1 amounting to #bca pounds dry weight1 was washed and at the same time given a light brush for one hour only1 after which it was bleached with #ag per cent of bleach without the addition of acid4 ,since the preceding paper appeared somewhat weak and had a low tearing quality1 it was decided to use a furnish of #ae4g per cent bleached sulphite and #hd4c per cent bleached hemp-hurd stock4 ,after loading with #ac4a per cent of clay and sizing with #a4a per cent of resin size1 the furnish was given a medium brush for one hour1 tinted1 and run on to the machine at #gj feet per minute4 ,the stock gave no trouble on the machine1 but it was impossible to judge the effect of the ,jordan refiner1 because through an oversight the machine chest had not been cleaned since previous use on an unbleached yucca material4 ,it is believed1 however1 that sheet ,no4 #ach shows improvement in the preparation of the hurd pulp4 ,run ,no4 #aci was made from stock of cooks ,nos4 #cjd and #cje1 in which still more caustic soda was employed and the time and temperature of cooking were increased1 giving a yield of total fiber of #dj4g per cent of the sieved or #ci4d per cent of the unsieved hurds4 ,the cooked stock still seemed to be undertreated1 but it must be remembered that in working with any new raw material it is impossible to know in advance how the properly treated material should appear4 ,a washing of one hour was given while the roll was lowered from a light to a medium brush1 after which the stock was bleached with #ag4a per cent of bleach without the aid of acid4 ,since sulphite stock improved the previous paper1 this bleached stock was used in a furnish of #af4f per cent sulphite and #hc4d per cent hurds1 loaded with #af4g per cent clay1 sized with #a4d per cent resin size1 given a medium brush of two hours1 tinted1 and run on to the machine at #gj feet per minute4 ,the ,jordan refiner seemed to have little effect in reducing shives and was therefore left just off4 ,no trouble was experienced with the stock on the machine1 and the sheet is an improvement over previous samples4 ,run ,no4 #adj was made from cooks ,nos4 #cjf and #cjg1 in which more caustic soda was employed than in any previous cooks and at a higher concentration1 the fiber yields of which averaged #cg4c per cent of the unsieved hurds4 ,not much improvement was apparent in the cooked stock1 in spite of the increased severity of cooking4 ,the stock was washed and given a medium brush for one hour1 bleached with #aa4i per cent of bleach1 assisted with one-half pint of oil of vitriol1 and made into a furnish of #ad4i per cent sulphite and #he4a per cent of the hurd stock4 ,after loading with #ad4g per cent of clay and sizing with #a4bh per cent of resin size1 the furnish was given two hours' medium brush1 tinted1 and run on to the paper machine at #gj feet per minute4 ,again the ,jordan refiner did not seem to reduce the wood shives sufficiently1 and it was left just off4 ,no trouble which could be attributed to the stock was experienced on the paper machine4 ,the color of the resulting paper is due to the use of too little blue in tinting and probably in some measure to the use of too low a percentage of bleach4 ,run ,no4 #ada was made from the stock of cooks ,nos4 #cjh and #cji in practically the same manner as run ,no4 #adj4 ,the stock was washed and brushed one hour1 bleached 7the record of the amount of bleach was lost71 made into a furnish of #ad4g per cent of sulphite and #he4c per cent of hurd stock1 loaded with #ad4i per cent of clay1 sized with #a4bf per cent of resin size1 given one hour at a medium brush1 tinted1 and run on to the machine4 ,the ,jordan refiner was able to reduce the wood shives to a somewhat greater degree than in previous runs and was held at a medium brush4 ,the stock acted well on the machine and produced a sheet of better quality than any preceding1 with the exception of the color1 which was due to using too small a quantity of blue4 ,among the cooks made for run ,no4 #adb are ,nos4 #cab and #cac1 in which the concentration of the caustic soda was raised to #aac and #aaf grams per liter and the percentage employed was also increased4 ,in spite of these increases the stock from these two cooks did not show any appreciable improvement when dumped from the rotary4 ,stock from cooks ,nos4 #caj1 #caa1 and #cab was given a medium brush and washing of one hour1 bleached with #aj4ie per cent of bleach1 made into a furnish consisting of #ae4b per cent of sulphite and #hd4h per cent of hurd stock1 loaded with #ae4b per cent of clay1 sized with #a4bh per cent of resin size1 given a medium brush for one hour1 tinted1 and pumped to the stock chest4 ,stock from cooks ,nos4 #cac and #cad was treated in exactly the same manner1 except that #aa4d per cent of bleach was used4 ,it was pumped to the stock chest and mixed with the furnished stock from cooks ,nos4 #caj1 #caa1 and #cab4 ,a medium ,jordan brush was given the stock and it acted well on the paper machine1 which was speeded to #ge feet per minute4 ,there seems to be a tendency in the hurd stock to crush a little at the dandy roll1 and although the marks are not removed by the calender stack which was employed in those tests it was found that one nip on the supercalenders renders them practically imperceptible and it is believed that the proper size and weight of calender stack would entirely remove these marks4 ,all of the papers produced up to this point are somewhat lacking in the bulk desired in a book paper2 therefore1 in the two following runs soda-poplar stock was included in the furnishes4 ,in run ,no4 #adc stock from cooks ,nos4 #cae and #caf was given a medium brush and washing for one hour and was medium brushed for one hour more1 bleached with #aa4c per cent of bleach assisted with one-half pint of oil of vitriol1 made into a furnish of #af4e per cent of sulphite1 #bb4c per cent of soda poplar1 and #fa4b per cent of hurd stock1 loaded with #bb per cent of clay1 sized with #a4ch per cent of resin size1 given a hard brush for one hour1 tinted very strongly1 and pumped to the stock chest4 ,this stock was beaten to a greater extent than in previous runs4 ,the stock was run on the paper machine at a speed of #ge feet per minute1 using a medium ,jordan brush1 and no trouble whatsoever was experienced4 ,not over #b pounds of broke was produced during the whole run1 and that was in the threading of the machine4 ,the color of the sheet is entirely satisfactory for many uses4 ,the wood shives apparently were reduced to a satisfactory degree4 ,experienced paper makers commented very favorably on the running of this furnish and the quality of the paper produced4 ,run ,no4 #add was intended as a duplicate of run ,no4 #adc4 ,stock from cooks ,nos4 #cag and #cah was given a medium brush and washing for one hour and a further medium brush of one hour1 bleached with #aa4d per cent of bleach1 and made into a furnish composed of #ae4e per cent of sulphite1 #bc4e per cent of soda poplar1 and #fa per cent of hurd stock1 loaded with #ba4d per cent of clay1 sized with #a4ag per cent of resin size1 hard brushed for one hour1 tinted by the expert colorer of the company1 and pumped to the stock chest4 ,stock from cooks ,nos4 #cai and #cbj was treated in exactly the same manner except that the stock was bleached with #ab4a per cent of bleach and pumped to the stock chest to mix with the former furnish4 ,the stock acted very well on the machine1 which was speeded to #ge feet per minute1 with the ,jordan refiner set at a medium brush4 ,the sheet is as good1 if not better1 than that of run ,no4 #adc1 and it is also a good illustration of the extent to which proper tinting will enhance the general appearance of a paper4 ,the poor appearance of the samples of previous runs is due largely to lack of proper tinting4 ,various degrees of whiteness1 however1 are demanded by the trade4 ,,comparison ,,of ,,the ,,tests ,,and ,,commercial ,,practice4 ,in work of this nature and on this scale it is practically impossible to arrive at a cost figure which would be susceptible of commercial interpretation1 and in this preliminary publication nothing will be attempted beyond a comparison of the process used with the hurds with that process commercially applied to poplar wood4 ,the process last used with the hurds should not be regarded as final1 satisfactory1 or most suitable1 as it has been shown that progress was being made up to the conclusion of the work4 ,in comparing the method of using hurds with the method of handling poplar wood1 a difference is apparent on the delivery of raw material at the mill4 ,ordinarily1 poplar is received at the mill in the form of logs about #d feet in length1 which may be stored in piles in the open4 ,hurds very likely would be received baled1 and it would seem advisable to store them under cover for the following reasons3 7a7 ,baled hurds would probably absorb and retain more water during wet weather than logs of wood1 thereby causing excessive dilution of the caustic liquor2 7b7 prolonged excessive dampness might create heating and deterioration unless the hemp were properly retted2 7c7 wet hurds could not be sieved free from sand and chaff4 ,should further work show that the first two reasons need not be taken into consideration1 the third objection might be overcome by sieving the hurds before baling4 ,even then1 it is probable that baled hurds stored in the open would accumulate and retain considerable dirt from factory chimneys1 locomotives1 and wind4 ,checked pulp wood exposed in the open invariably suffers from these causes4 ,in the preparation of the raw material for the digesters there is likewise considerable difference between hurds and poplar wood4 ,the former apparently requires only a moderate sieving to remove sand and chaff1 which operation doubtless would require only a small amount of labor and the installation of some simple machinery of low power consumption4 ,in preparing poplar for digestion1 the #d-;foot logs are chipped by a heavy1 comparatively expensive chipper of high power consumption1 after which the chips are sorted by sieving1 the large pieces being rechipped4 ,there would be a noteworthy difference in the installation1 operating1 and depreciation costs of the two equipments1 and this difference would counterbalance to a considerable extent the difference in cost of raw material storage4 ,it is possible that in the use of the chip loft more care would have to be exercised in using hurds because of the tendency of the bast fiber to cause lodgments1 but this should not be considered a serious difficulty4 ,the weight of hurds which are capable of being charged into a rotary is a decidedly unfavorable factor4 ,the weight of a cubic foot of hurds varies somewhat with the proportion of bast fiber1 but averages about #e4d pounds1 which1 compared with a cubic foot of poplar chips at #h4ic pounds1 represents a digester charge of #fj4e per cent of the weight of a poplar-wood charge1 or1 in terms of fiber capacity1 the hurds charge would yield #ch4f per cent as much fiber as the wood charge4 ,the hurds upon being baled for transportation may be broken and crushed to such a degree that the weight of the charge may be increased1 and it might be found possible to increase the charge weight by steaming or by the employment of tamping devices4 ,this small weight of charge constitutes one of the most serious objections to the use of hurds in paper manufacture4 ,in those tests in which the most satisfactory results were obtained1 the cooking conditions were #bi4e per cent of caustic soda at a concentration of #ajg grams per liter and a causticity of #hd4j per cent acting at a temperature of #agj ,c4 for five hours1 or a total time of seven hours4 ,the steam condensation in the rotary used for these tests was abnormally high1 due to the fact that the steam supply pipe was uncovered for a considerable distance and the rotary was entirely uncovered4 ,it is believed1 therefore1 that a larger amount of caustic was necessary than would otherwise have been the case4 ,this belief is strengthened by the quality of the waste liquor from one of the later cooks1 which gave on analysis #af4he grams per liter of free caustic soda and showed a causticity of #bg4ge per cent4 ,these data show that only #fg4c per cent of the total caustic employed was actually consumed in the cooking operation1 which percentage is lower than obtains in practice4 ,the stock from this cook was bleached with #aa4e per cent of bleach4 ,but even as the figures stand1 the comparison with poplar cooking practice is as follows3 #bi4e per cent caustic soda used as against #bb to #be per cent2 #ajg grams per liter as against #ajj to #aaj2 #hd per cent causticity is little different than obtains in practice2 #agj ,c4 is about commercial practice2 five hours at pressure as against four to six hours2 seven hours' total time as against possibly six to eight hours2 #aa4e per cent bleach as against #h to #aj per cent4 ,thus1 it is evident that the cooking conditions employed were slightly more severe and expensive than those in commercial use with poplar wood4 ,the yield of total fiber obtained from the hurds may be placed at #ce per cent of bone-dry fiber calculated on the bone-dry weight of hurds used1 or #cc4a per cent of air-dry fiber calculated on air-dry hurds4 ,the yield of bleached fiber was not determined in this preliminary work1 but may be safely estimated as #cj per cent1 which is low when compared with a yield of about #dg per cent of bone-dry bleached fiber from bone-dry poplar wood4 ,it is believed quite possible that satisfactory cooking conditions may be found which will give a higher yield than was obtained during these tests4 ,the stock should be classed as easy bleaching1 and #aa4d per cent of bleach is a satisfactory figure1 although a little high4 ,as to beating cost1 in the last two and most satisfactory tests the total washing and beating time was three hours1 which may be about an hour more than ordinarily is used in making papers of this grade1 although the practice varies to a considerable extent4 ,in regard to furnish1 there is such a diversity of practice that it is difficult to make a comparison1 but if the hurd stock can be produced as cheaply as soda-poplar stock1 the furnish used in these last two tests should be regarded as satisfactory to the book and printing paper manufacturer4 ,the finish of the paper was not all that might be desired1 but that was due almost entirely to the calender stack available for the work1 which was composed of nine light rolls1 many of which were about #f inches in diameter and which had not been reground for some time4 ,from a small test on a large calender stack it was readily shown that the paper produced is capable of taking a satisfactory finish4 ,this comparison1 satisfactory in many respects1 develops two factors which are decidedly unfavorable to hemp hurds1 namely1 raw-material storage and digester capacity1 and they must be taken into full account in considering the paper-making value of this material1 although it should be recognized that investigation may result in the material improvement of these conditions4 ,moreover1 it is not at all improbable that further investigation would develop more satisfactory treating conditions and more suitable furnish compositions1 and the belief in this possibility is strengthened by the fact that material progress was being made at the conclusion of this preliminary work4 ,calculations on the raw material and acreage for a permanent supply for a pulp mill producing #be tons of fiber a day for #cjj days per annum1 or #g1ejj tons per annum1 give the comparison between hurds and wood shown in ,table ,,ii4 ,,table ,,ii4--,comparison between wood and hemp hurds4 ---------------------------------------- ----------------------------- ,acres required for sustained supply4 ------------------- ,raw material ,annual ,material4 ,pulp yield4 required per growth ,for ,for #a ton year4 per acre4 #be-ton of fiber mill4 per year4 ---------------------------------------- ---------------------------- ,wood ,two cords #ae1jjj cords #j4cg cord #dj1ejj #e4d yield #a ton 7about of fiber4 #j4ee ton74 ,hemp hurds ,one ton #be1jjj tons #b4e tons #aj1jjj #a4cc yields #fjj pounds of fiber4 ---------------------------------------- ---------------------------- ,the most important point derived from this calculation is in regard to areas required for a sustained supply1 which are in the ratio of #d to #a4 ,every tract of #aj1jjj acres which is devoted to hemp raising year by year is equivalent to a sustained pulp-producing capacity of #dj1ejj acres of average pulp-wood lands4 ,in other words1 in order to secure additional raw material for the production of #be tons of fiber per day there exists the possibility of utilizing the agricultural waste already produced on #aj1jjj acres of hemp lands instead of securing1 holding1 reforesting1 and protecting #dj1ejj acres of pulp-wood land4 ,the annual growth per acre1 although decidedly in favor of hurds1 has little bearing on the project1 because the utilization of the hurds is subordinate to the raising of hemp1 and the paper manufacturer probably could afford to use only hurds resulting from the hemp industry4 ,,physical ,,tests ,,of ,,the ,,papers ,,produced4 ,samples of paper produced in the seven tests were submitted to the ,leather and ,paper ,laboratory of the ,bureau of ,chemistry4 ,the report of that bureau on its tests is given in ,table ,,iii4 ,,table ,,iii4--,report of the ,leather and ,paper ,laboratory of the ,bureau of ,chemistry on papers manufactured from hemp hurds4 ---------------------------------------- ----------- ,weight of #ejj ,laboratory ,run sheets4 ,thickness1 ,no4 ,no4 ,ash4 ------------------ #a_/ajjjj4 #be by #ch4be by #dj4 ---------------------------------------- ---------- ,per ct4 ,pounds4,pounds4 #caegj #add #ac4i #dh #ej-a_/b #cc #caega #adc #ad4e #di #ea-a_/b #ce #caegb #adb #i4e #di-a_/b #eb #cc #caegc #ada #aj4i #dh #ej-a_/b #ch #caegd #adj #aa4d #db #dd #cj ,transcriber's #caege #aci #ac4d #ee #eh #dj note3 ,table ,,iii #caegf #ach #aj4d #ef #ei #dj continues below ---------------------------------------- ---------- ---------------------------------------- -------------------------------- ,strength 7,mullen74 ,folding endurance4 ,laboratory ,strength ,no4 ------------------------ factor ------------------------ 7#be by #dj1 ,average4,maximum4,minimum4 #ejj74 ,longitudinal4,transverse4 ---------------------------------------- ----------------------------- #caegj #ae4j #ag4j #aa4j #j4cj #e #c #caega #ad4j #ad4j #ac4j 4#bh #d #d #caegb #ai4j #bj4j #ai4j 4#cg #h #f #caegc #af4e #ah4j #aa4j 4#cc #aj #h #caegd #ad4e #af4j #ac4j 4#cc #g #f #caege #ai4e #bj4j #ag4j 4#cd #h #e #caegf #bj4j #bj4j #ai4j 4#cd #bc #ae ---------------------------------------- ----------------------------- ,there is no system of numerically recording the general appearance and look through of a paper1 but it can be stated that only papers ,nos4 #adc and #add are satisfactory in these respects1 the other samples being more or less thickly specked with shives4 ,the general character and tests of these papers correspond very closely with ,no4 #a machine-finish printing paper1 according to the specifications of the ,united ,states ,government ,printing ,office1 which call for a sheet not exceeding #j4jjce inch in thickness1 strength not less than #ab points1 free from unbleached or ground wood pulp1 and ash not over #aj per cent4 ,the strength factor of such papers is about #j4bh4 ,the ash should not be over #aj per cent for this grade of paper1 but in spite of the larger amount used the physical tests are sufficiently high4 ,it is to be noted that the physical tests of samples ,nos4 #ach to #adb1 inclusive1 are higher than in ,nos4 #adc and #add1 in which #bc per cent of soda poplar was used1 which shows clearly that hemp-hurd stock imparts strength and folding endurance to a greater extent than does soda-poplar stock4 ,from these preliminary tests it would be concluded1 therefore1 that hemp-hurd stock acts similarly to soda-poplar stock1 but will produce a somewhat harsher and stronger sheet and one of higher folding endurance4 ,undoubtedly1 there is more dirt in the samples than would be tolerated by the trade1 but this was to be expected1 since in this preliminary work the raw material was sieved by hand screens instead of by automatic machines which would sieve more thoroughly4 ,,conclusions4 ,there appears to be little doubt that under the present system of forest use and consumption the present supply can not withstand the demands placed upon it4 ,by the time improved methods of forestry have established an equilibrium between production and consumption1 the price of pulp wood may be such that a knowledge of other available raw materials may be imperative4 ,semicommercial paper-making tests were conducted1 therefore1 on hemp hurds1 in cooperation with a paper manufacturer4 ,after several trials1 under conditions of treatment and manufacture which are regarded as favorable in comparison with those used with pulp wood1 paper was produced which received very favorable comment both from investigators and from the trade and which according to official tests would be classed as a ,no4 #a machine-finish printing paper4