INDUSTRIAL AND E-VGINEERING CHEMISTRY
912
derived from blue gas if the enriching gas has a high heating value per cubic foot. This relation must be borne in mind when we consider the relative values of various types of enriching materials. We can show roughly the relative prices a t which the various materials can compete as gas enrichers under assumed conditions and more particularly bring out the fact that the value of these various materials for gas enrichment cannot be judged solely on a price per gallon or even on a price per therm of heat units basis, but must be looked at from the point of view of total cost of the final gas. We have computed the cost of the materials which enter into the production of gas of various heating values enriched by various methods and with various prices for the enriching materials and, based on gas oil a t six cents a gaIlon, we have obtained comparable prices for the various other substances. In a general discussion it is not possible to consider quantitatively all the various factors which will affect relative
Vol. 20, No. 9
costs-such as the effect of various gravities of gas resulting from the various methods considered, the relative amount and value of by-products, the value of the various materials as reserve supplies more easily stored than gas, and the questions of plant safety and operating convenience. These questions must be considered by each plant engineer for his own operating conditions. Table I gives a comparison of values on a heat-unit basis, which must be modified to suit local conditions as mentioned above. The cost of catalytic condensation is not serious from the point of view of energy loss, but in this case careful consideration would have to be given to the design and cost of the equipment necessary to carry out the process. It should be noted, also, that the very high heating value of butane vapor per cubic foot makes its value per gallon from 10 to 12 per cent above that of gas oil, although its heating value has been assumed as only 6 per cent greater than the gases which can be obtained from a'gallon of gas oil.
Potassium Xanthate as a Soil Fumigant-11' E. R. deOng2 and Jocelyn Tyler3 UNIVERSITY OF CALXSORNIA, BERKELBY, CALIF.
The rate of decomposition of potassium xanthate, the inhibition of s e e d l i n g as measured by the evolution of carbon disulfide, is xanthate (KS2COCZHe) growth-a serious criticism of given when combined with hydrochloric acid and with as a soil fumigant was xanthate when used alone. the superphosphate of the fertilizer trade. Laboratory discussed two years ago4 from Acids in liquid form cannot measurements have been made of the rate of penetrathe chemical standpoint, and be used in a dilute state in tion of carbon disulfide into both loose and packed the biological effect was then soil on account of reaction sandy and heavy clay soils. d e t e r m i n e d with beetles. with soil bases, but under The toxicity of xanthate has been tested principally Since then, in addition to laboratory conditions t h e y against the root-knot nematode. It has been shown further chemical experiments, h a v e been combined with that a complete kill is possible i n the laboratory with two years of field experiments, aqueous solutions of xanthate the different stages of the nematode, while good consupplemented by laboratory before applying to the soil. trol has been obtained i n field experiments. tests, have been conducted on The best results have been the attemrked control of the obtained with applications of root-knot nematode, Caconema radicicola (Greef) Cobb = the powdered xanthate intimately mixed with the superHeterodera radicico2a (Greef) Muller. From this work phosphate of the fertilizer trade alone and with superfine conclusions have been reached as to the possible value of sulfur. xanthate for field use under limited conditions. These data COMPARATIVE VALUESOF CARBONDISULFIDEAND X ~ N also contribute to our general knowledge of soil fumiga- THATE-The advantages of xanthates as fumigants over tion. carbon disulfide itself are:
HE value of potassium
T
A
Chemical Considerations
The chemical and physical properties of xanthate, as affecting this problem, were reviewed in detaiI in the first paper so will be touched upon but briefly. Xanthates are compounds of xanthic acid, such as potassium ethyl or sodium ethyl xanthate, the free acid being unknown. On decomposing it releases carbon disulfide, to which apparently the toxicity is due. Decomposition occurs, however, very slowly in a neutral or basic medium: hence it has been found necessary to include an acid with all soil applications. This makes possible the maximum decomposition of xanthate in a variable length of time depending on the type of acid used. High concentrations of gas in the soil are thus made possible, while the early decomposition of the salt prevents Received April 2, 1928. 2 Present address, First National Bank Bldg., Berkeley, Calif. * The senior author reports the chemical phases of the subject, as well as the field work and beetle tests. The junior author contributes the laboratory data on nematode fumigations. IND. ENG.C H E M . , 18,:52 (1926). I
'
(1) High solubility in cold water, thus permitting the solution to be carried downward into the soil by irrigation water or heavy rains. Carbon disulfide when used alone does not permit of a uniform distribution through the soil and the gas does not penetrate downward readily into dense subsoil. Emulsions of carbon disulfide and water are now being used in the Japanese beetle work, but it is often inconvenient to make the emulsion and this may break before penetrating deep into the soil. (2) A graduated release of carbon disulfide from xanthate is possible, based upon the formula used, permitting either quick evolution of gas or a slow release prolonged over a period of 10 t o 12 days, while carbon disulfide volatilizes very quickly and dissipates at a corresponding rate except in heavy or in very wet soils. ( 3 ) Potassium xanthate is a safer chemical to handle than carbon disulfide, as it has no explosion hazard.
DECOMPOSITION OF XANTHATE-The rat€! O f decomposition of potassium xanthate (purity 95 per cent +) varies with the temperature but normally requires several hours to complete, even when in solution with equivalent amounts of acids. In soil work the amount of decomposition varies with the complex of the medium. It will be seen in Table
I N D U X T R I A L A S D E.VGI,VEERln'G CHEMISTRY
September, 1928
I that about 75 per cent of the decomposition occurs during the first 3 hours when the theoretical amount of acid has been used. This point is important in field work, for if moisture is present in the chemicals when mixed much of the gas may be lost before incorporating into the soil. A slower rate of decomposition, as indicated by the mortality data in Figure 1, occurs when xanthate is combined with but a small amount of phosphate and sulfur is added. The reaction of the sulfur depends on its conversion into sulfuric acid by oxidation and, since this is slow, an excess of sulfur should be used. The range in the rate of reaction should not be considered detrimental but rather gives flexibility to fumigation practice. Table I-Decomposition Rate of Potassium Xanthate with Hydrochloric Acid and with Superphosphate TIME HC1 SUPERPHOSPHATE Hours P e r cent Per cenl 3 24 48
75 6 81 8 96 6
73 3 77 3 88 1
The reaction between xanthate and superphosphate proceeds normally in moist soil but very dry soils require irrigation. The irrigation should be just heavy enough to carry the dissolved xanthate down to the desired depth without saturating the soil as this retards the movement of the gas through the soil. When combining the two salts where no moisture is present, water to the amount of 12 to 16 per cent of the total weight should be added. It must be recognized that the decomposition of xanthate is decidedly impeded in the soil, thus demanding heavier dosages than would otherwise be necessary. MOVEMENT OF CARBONDISULFIDE THROUGH Son-The diffusion of the vaporized carbon disulfide from xanthate was measured in the following way: Five grams of xanthate, mixed with 12.75 grams of phosphate, were buried 2 ft. (61 cm.) in the ground. .4ir samples of from 16 to 30 liters were then drawn a t varying intervals of time and a t different distances from the sample. The concentration of the carbon disulfide was determined by the method devised by Huff.5 The experiments were made both in a very stiff adobe soil and in one that is almost a pure sand. The results of many experiments are summarized as follow: All soils tested were found t o adsorb a large amount of gas. Wet soil adsorbs more gas than dry soil. The rate of adsorption by the adobe soil is approximately double that by sandy soil This reaction is decidedly different from that of hydrocyanic acid gas, as shown by deOng.6 I n his experiments he found that the adsorption of hydrocyanic acid gas by pure sand is practically nil, while the gas is adsorbed or reacts chemically with the clay in direct proportion to the amount present. This difference in the behavior of the two gases probably explains the dissatisfaction sometimes resulting from the use of cyanide as a soil fumigant. Measurable amounts of carbon disulfide were recovered 6 to 18 inches (15 to 46 cm.) laterally from the point where the xanthate was placed from 3 to 5 days after the sample was buried. Measurable amounts of carbon disulfide were recovered from the undisturbed sandy subsoil 5 inches (13 cm.) below the sample and a trace, still lower. h'o carbon disulfide was recovered from the undisturbed adobe subsoil immediately below the decomposed xanthate.
Biological Experiments
TOXICITY TESTSWITH BEETmS-The toxicity of xanthate alone and in combination with other chemicals was first measured in the laboratory by adding xanthate, and other chemicals as indicated, to sand in flower pots a t dosages corresponding to 300 pounds of xanthate to an acre. A constant supply of moisture was obtained by covering the sand for the time indicated with three thicknesses of paper. Ladybird beetles, Hippodamia conelergens Guerin, were used as the indicator. This is not a soil-inhabiting insect, but it 5
J . A m Chem. Soc , 4 8 , S l (1926). Agr Research, 11, 421 (1917).
*J
913
hibernates in great numbers in the debris of the forest floor and hence is in a measure adapted to the confinement of soiI practice. Several series of beetles were run in preliminary experiments to determine satisfactory types of cages and the desired amount of moisture. The procedure finally adopted was the confining of about fifty beetles in small wire boxes, open on all sides, in freshly treated soil (immediately after the chemicals were added) for a period of 48 hours. The number of dead beetles was determined a t this time. Other series of beetles were placed in the same soil 5, 10, and 15 days after treatment, as indicated in Figure 1. Potassium xanthate was used alone to check against xanthate combined with the theoretical amount of superphosphate required for neutralization, and in the third series with one-third the theoretical amount of phosphate and with an amount of fine sulfur equal to that of the xanthate used. This provided an excess of sulfur over that theoretically required to convert into sulfuric acid and thus neutralize the xanthate used. The re-
Figure 1-Fumigation
T/OL= //Y DkYd Experiments with Beetles
sults from the different treatments are shown in Figure 1. The tendency of the mortality rate to drop about the fifth day and then rise later has been shown in all fumigation experiments with xanthate. The curve for xanthate and phosphate shows a distinct peak with a corresponding rapid drop, while the xanthate, phosphate, and sulfur combination gives a prolonged high concentration or, in other words, a flat type of curve. This seems particularly suited to nematode fumigation on account of the irregular appearance of the larvae. For insects which are uniformly susceptible in all stages, the quicker generation of a larger amount of carbon disulfide would probably be desirable. LABORATORY EXPERIMENTS WITH SEMAToDEs-yematode larvae occur in the soil, living in the water film. Two treatments were tried for infested soil-direct application of the chemicals as under field conditions ( B ) , and use of fumes only, a procedure limited to the laboratory ( A ) . (11) Fumigatioris of soil. The theoretical possibilities of killing by gases liberated when acid is added to xanthate are shown in Figure 2. Here it is seen that 90, 95, and 100 per cent kill of nematodes is possible in small volumes of loose soil. At low concentrations a 48-hour exposure was necessary for good results. Curve A shows the best kill, and these results were well confirmed. The same fumigation procedure was used for curves A and C, and the time was the same. The nematodes in B, C, and D were counted microscopically, while in A the counts were made on the basis of infecting activity. This indicates that a proportion of the worms which appeared alive a t a direct microscopic examination were actually weakened to a point where they were no longer dangerous as parasites, and did not attack susceptible plants grown in the treated soil (curves B, C, and D).
* INDUSTRIilL A N D ENGIYEERING CHEMISTRY
914
Curve E shows a fumigation of larger volumes. It was a lower kill proportionately because there was a chance for the escape of fumes from the jars used. Still it follows the direction of the other curves. It is also useful as a standard of comparison of the fumigations (Figure 2) with the direct treatments (Figure 3). In all these graphs the percentage of kill is computed by comparison of each test with its own check. All the dosages of xanthate are computed on the basis of volume of 300 cc. to be treated, whether it be amount of soil in a pot or volume of a fumigation chamber. T h e microscope counts are not percentage mortality but percentage efficiency of f u m i g a t i o n , because allowance was made for fatalities in the controls. The different e x p e r i m e n t s have thus been reduced to comparable terms. ( B ) D i r e c t treatments of soil. When the xanthate is applied directly to the soil, superphosphate (Figure 3, curve X) Figure 2-Fumigations of Soil for Nematode Control appears to be a more A-48-hour fumigation; kill determined b y reliable neutralizing infection of plants B-65-hour fumigation; kill determined by acid than sulfuric acid direct count C-48 hour fumigation; kill determined by (curve Y ) . direct count Curve E of Figure D-24-hour fumination; kill determined b y 2 is also plotted on direct c o m t E-48.hour fumigation; not air-tight, deterthis graph for comrutnations b y infection of plants parison of fumigation with direct application. The unsealed fumigation, E , is less economical than the tight fumigations, and is more comparable in results with the direct soil treatments. The conclusion from this comparison is that a high proportion of the chemicals is lost by direct contact with the soil. ( C ) Penetration of galls. The eggs of the nematode are laid inside galls on the roots of the host plants. These galls, therefore, contain the infective material. They were treated by fumigation in a closed cylinder, with the following results:
a
KILL Per cent 44 85 98 100
TIME Hours 48 24 72 96
XANTHATE SPACEFUMIGATED Gram
cc.
0.20 0.57 0.40 0.30
300 300 300 300
The easiest route of penetration would be through the cut ends of these roots. Time of fumigation and amount of xanthate are shown as complementary factors. This experimeut has not been duplicated under field conditions. Summamj of dosages. (A) Larvae in light soil were killed by fumigation in 48 hours with 0.35 gram of xanthate per 300 cc. of space to be fumigated (equal to 2750 pounds per acrefoot, plus propet amounts of acids). For galls containing eggs it was necessary to treat during 72 hours with Oa40 gram of xanthate. (B) I n pots, direct, 0.80 gram per 300 cc. gave almost complete kill (98 per cent) of free-living larvae, while 0.80
Vel. 20,
KO.
9
gram failed to kill larvae and eggs in fresh-cut galls buried in loam soil, and 1.0 gram left infective eggs alive inside galls on tomato roots, although it killed the plants. From this last test it will be seen that the practical field problem is a more complex one, involving roots as well as the difficulty of penetration to all parts of the soil. I n the laboratory, however, advantage can be taken of the gaseous property of this material, even for fumigations of soil, a t the same time avoiding chemical reactions with unknown soil salts. Direct soil applications are less thorough, but it is possible with high dosages to effect 100 per cent kill in flowerpot tests. FIELDTESTSON NEMATODES-Aseries of field tests to determine the value of potassium xanthate as a control for the root-knot nematode was made a t the Citrus Experiment Station, Riverside, Calif. (Table 11) The work was done on a plot of l l / z acres, in a soil classified as a placentia loamy sand. The soil is of a decomposed granite origin, containing a noticeable amount of mica. It passes through fine mesh sieves readily by means of a running stream of water. Watermelons were grown in all the plots in the spring following the treatments, to indicate the degree of infestation remaining after the application. The field was divided into eight sections 40 by 360 feet, each section being divided into plots 20 by 40 feet with buffer strips 10 by 40 feet between each test plot. The buffer strips prevented the carrying of soluble chemicals from one plot to another, but they also led to a distribution of nematodes from the checks into treated areas. This will be seen from Table 11, where bracketed figures show heavily infested plants on the boundary between test plots and buffer strips and on the side from which the irrigation water flowed. The area of the individual plots corresponded to 1/64 acre with corresponding amounts of chemicals used in each instance. The xanthate and superphosphate or sulfur were thoroughly mixed together, then broadcast by hand uniformly over the different plots and plowed under. The use of the sulfur, of course, implies its oxidation to the acid form, and for this reason a precipitated form of sulfur was used which results as a by-product from purifying illumi100
90
80
m $4
r-;
6% u E
a,
GRAMS X A ” A T E PER 300cc
Figure 3-Direct
Application of Chemifals to Soil for Nematode Control X-Xanthate neutralized with superphosphate Y-Xanthate neutralized with sulfuric acid E-Fumigation curve repeated for comparison with Figure 2
I-VD USTRIAL AND E.VGIiVEERING CHEMISTRY
September, 1928 Table 11-Field
Exueriments w i t h P o t a s s i u m X a n t h a t e a s a Control for R o o t - K n o t N e m a t o d e
2 3 4
Xanthate
Sulfur
Phosphate
Lbs. 300 600 300
Lbs. 300 (gas)d 300 (gas)
Lbs.
600
5
600
6
400
500
1200
; 3
None
5
v,
600
6
300 600
100 200 100
1 2 3
1
b
500 1200
Applied May 9, 1926. Applied October 9, 1925.
300 2 00
300 600
Xone
11 14 17
20 23 26
27
31
20
28 43
9 2
15
5
N u m b e r of plants 6 11 10
Heavy
6 6
9
23
8
6
9 22
3 4
0 9
5 10
5 17
5 6
8 6
1 0
8
9 1 4 15
14 9 2 (2)
6 00
5 4 14 17 20
300 600
1s 3
300
Light
13 5 2 (2)
1 2 3 4
300 600 300 4 600 300 5 600 6 VIIIb 1 300 2 600 300 3 4 600 5 300 6 600 Grand total average percentage Check: Number of plants Per cent VI11 5 Percentage 6 Percentage a
Heavy
1200
1200
5 6
VII“
Light N u m b e r of plants
4
111. I V , VIa
SPRINGAPPTXATION
DEGREE O F INFESTATION
1
IIb
I
FALL APPLICATION
CHEMICAL USED SECTION PLOT
Ia
915
(1) (1) 4 0
(1)
10 2s 12
6 (2)
7
2
2
2
300 300 e 00 60.6 100.0 18.5
26.3 245.0 45.4
12.7 194.0 36.0
49.3
27.3
23.3
clean, 8 8 . 2 clean, SO. 6 c
d
Watermelon used as test plant. Corresponding to 300 pounds t o an acre.
nating gas. This material known as “gas sulfur” oxidizes in the soil more rapidly than any sulfur experimented with, and for this reason will promote a rapid decomposition of xanthate. A difficulty in the formation of the acid medium necessary to decompose xanthate is the varying alkalinity of the soil. Where this is a t all pronounced the best results wlll probably be secured by using both superphosphate and ail excess of quickly oxidizing sulfur in the fall of the year when high soil temperatures favor rapid oxidation. It will be noted that the fall application was superior to that made in the spring, both in freedom from infestation and in the number of plants obtained. The fall treatment showed a better stand of watermelons than did the spring, complete failure or marked reduction coming only in plots where xanthate was used alone. The watermelons were planted May 26, just 23 days after the spring application of xanthate. Replanting, which was necessary on account of the poor stand, was on June 10. Even a t this time the plots showed poor germination where little or no phosphate had been used to decompose the xanthate. This illustrates the value of phosphate in causing quick decomposition, thus giving a high concentration of gas in the soil and preventing the inhibition of germination of seeds. The greatest freedom from nematode infestation was obtained in section VIII, plot 5, with a percentage of 88.2 per cent clean, using potassium xanthate and superphosphate a t the rate of 300 pounds each to the acre. The next highest in degree of cleanness, 80.6 per cent, was plot 6 of the same section using 600 pounds of xanthate and an equal amount of phosphate. The variation between these two plots is within experimental error and is confirmed by the results found in other plots where similar dosages were used, indicating that
in this soil no advantage was secured by the larger dosage. By contrast the check shows 18.5 per cent clean, 45.4 per cent light, and 36 per cent bearing a heavy infestation. The check plot occupied about one-third of the area and contained a total of 539 plants. Certain factors must be kept in mind in interpreting the results reported: (1) The plots were necessarily very small and adjoining untreated areas, thus militating against complete control; (2) irrigation water was run lengthwise of sections and across plots in open ditches and also the sections were cultivated lengthwise a t least once. These factors complicated the results of treatment. Large plots of an acre or more in size should be used for confirmatory work. Summary of field experiments. The combination of sulfur and xanthate alone is decidedly inferior to phosphate combinations. Sulfur is, however, valuable ingredient in the formula, especially for neutralizing the alkalinity of the soil and aiding in the complete decomposition of the xanthate, provided a quickly oxidizing form is used and temperature and moisture conditions are favorable to the reaction. A suggested formula is 200 to 400 pounds of potassium xanthate to an acre, with a similar amount of superphosphate and 100 pounds of very finely divided sulfur. The smaller amount of chemicals is for very sandy soils and the larger amount for clay soils. Fall treatments are preferable to winter and early spring a p plications both from the standpoint of control and to prevent any danger to annuals which might be planted the following spring. Very thorough mixing of xanthate and other chemicals is necessary before plowing under. Plowing the xanthate in deeply is advisable, especially in heavy soils, as the gas does not readily penetrate hard clay soils.
I N D U S T R I A L A N D ENGINEERlNG CHEMISTRY
916
Potassium xanthate is a desirable soil fumigant but too expensive for acreage treatment except on crops yielding high profits, the cost for an acre being from $30 to $50. Eradication cannot be expected but only varying degrees of control for 1or possibly 2 years. The most satisfactory use of soil fumigation is in nurseries and beds and trucking or orchard soils.
VOl. 20, s o . 9
Xanthate has given practical control of the garden nematode in the 2 years’ experimentation, but the scope of the work is too limited to warrant recommending definite measures. Xanthate has not given control of the sugar beet nematode, Heterodera schachtii Schmidt.
Influence of Laundering on Cotton Fabrics’ Especially with Washing Agents Containing Sodium Perborate P. E. Raaschou and V. Ahrend Larsen LABORATORY FOR GENERAL TECHNICAL CHEMISTRY, POLYTECHNICAL COLLEGE, COPENHAGEN, DENMARK
On boiling cotton fabric, under definite conditions, with solutions containing 1 per cent of soda, 0.5 per cent of sodium hydroxide, l per cent of water glass, or l per cent of soap in hard water, reduction in tensile breaking strength increases with a n increasing number of boils, and t h e amount of this weakening is in t h e order in which these solutions are named. A mixture of 0.33 per cent of soap, 0.33 per cent of soda, and a small quantity of water glass (0.04 per cent in the lye) produces a very slight weakening. The addition of a small quantity of perborate (0.01 per cent of the lye) to these solutions increases the weakening, which in certain cases, however, is slight in comparison with the weakening influence of the pure laundering agent. The addition of increasing quantities of perborate (0.01 t o 0.15 per cent of the washing lye) to the standard lye causes a pronounced decrease in the strength. Special soiling of t h e fabric causes an additional weakening, when t h e boiling is done with the standard lye plus 0.05 per cent of perborate. On boiling with distilled water
(containing a trace of copper) a n especially pronounced weakening is found when the standard lye plus 0.05 per cent of perborate is used. A comparison of the breaking-strength tests with tests on the dissociation of the perborate during t h e boils shows t h a t boiling with a lye retarding the perborate dissociation results in a low degree of perborate-weakening, and vice versa. Thermostatic tests of the perborate dissociation show the factors accelerating and retarding the dissociation. Determinations of the quantities of ash and incrusted substances have been made, t h e latter according to a special method. In a single washing series a comparison has been made between the loss of weight and the loss of strength during the washing. An attempt has been made t o separate the total weakening during washing into the following individual factors-incrustation weakening, perborate weakening, and other causes of weakening.
H E Great War gave impulse to investigations concerning the injurious effects exerted on cloth by washing preparations, especially in countries suffering from scarcity of raw materials for textiles and washing agents, and during recent years interesting results have been obtained. A review of the more important washing investigations carried on in Germany was published in 1925 by Heermann.2 The principal object of the present investigation was to ascertain the degree to which cotton materials are weakened by being washed with so-called self-acting washing preparations-i. e., preparations containing perborates and other bleaching agents. In order.to procure a basis of comparison, washing tests were performed with the usual washing preparations, both separate and mixed with each other, paftly with and partly without sodium perborate. I n addition, to ascertain the purely mechanical wear occurring in home laundering, tests were conducted by the usual method of washing clothes by hand. The weakening of textile fabrics by washing preparations, in particular those containing sodium perborate, depends on the manner and the degree to which the fabrics are soiled. The fabrics were therefore soiled with various substances before they were washed-with mixed fruit juice for slight soiling, and with tea and claret for more or less intense soiling.
Preliminary investigations were also made of the processes of decomposition of the perborate in the various washing preparations and mixtures thereof employed, in order to find the relations between the quantity of perborate decomposed, or the speed of its decomposition and the extent to which the materials were weakened by the perborate. Further, quite independent, tests were made to ascertain the effect of various ions on the rate of decomposition of the perborate. Finally a study was made for some of the specimens in each series of washes, the contents of ash and incrusted substances formed by adsorption, on the fabric, of the laundering agents and the calcium salts of the washing water.
T
1 Received
November 6, 1926.
Revised manuscript received April
24, 1928. “Die Wasch- und Bleichmittel und Ihre Einwirkung auf Gewebe Nnd Game,” Verlag des deutschen Waschereiverbandes. e. V., Berlinkchterfelde. f
Materials Used
TEXTILES-TWO qualities of cotton cloth were used: Medium heavy unbleached cotton Weight, 133 grams per square square meter) Number of threads per cm., 33 in weft direction Yarn, 24 warp and 24 weft ( b ) Light cotton cloth: Weight, 36 grams per square square meter) Number of threads per cm., 48 in weft direction Yarn, 120 warp and 110 weft
(a)
cloth: yard (159 grams per in warp direction, 23
yard (13 grams per in warp direction, 46
WASHING WATER-Hard water (Copenhagen water supply) was used, the composition being:
