T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y V0l.- 12, No.
9 74
Owing t o the small size of the samples,’ no physical tests were made. The results of this experiment are shown in tabular form in Table 111. It is seen t h a t , despite the small size of the samples employed, the results obtained with the unextracted rubbers are in good accord with those previously found for similar quantities of t h e accelerator (Tables I and 11). I n the case of the extracted rubbers, however, this was not true. ’
TABLEI11 ---Sample
408-Sample Extracted Rubber (Ext. 36 Hrs.) Acetone Unextracted Ext. ~ 2 . 6 2 Rubber
----Unextracted Rubber
.
Control... Extra Light Magnesia 0.5Perceni Accelerator A 0.5 Per cent......
444---Extracted Rubber (Ext. 36 Hrs.) Acetone Ext. = 2.99
Sulfur Excess Sulfur Excess Sulfur Excess Sulfur Excess Coeffi- Coeffi- Coeffi- Coeffi- Coeffi- Coeffi- Coeffi- Coe5cient cient cient cient cient cient cient cient 0.580 0.831 1.009 1.000
...
.. .
...
. ..
1.874
1.294
1.290
0.459
3.132% 2.123
1.343
0 343
2.925
2.345
3.204
2.373
2.938
3.424
2.424
1.929
IO
The excess coefficients obtained were, indeed, so. little above their controls t h a t i t would appear t h a t a more complete removal of these extraneous substances would prove extra light magnesia to be almost inactive as a n accelerator. As Accelerator A functions equally well with both rubbers, either before or after extraction, when judged on the basis of the sulfur coefficients obtained, the results obtained with i t require no further comment. Final emphasis is placed upon the fact t h a t all results were obtained with mixtures of rubber, sulfur, and accelerator only, and t h a t the amounts of accelerators employed were small in all instances. CONCLUSIONS
I n view of the above experimental results, we are warranted in drawing the following conclusions: I-The activity of small amounts of magnesia as a n accelerator is largely of a secondary or contributory character, and acts in conjunction with, or obtains a response from, certain extraneous substances (probably nitrogenous) present in the rubber.’ 11-The activity of small amounts of magnesia is limited by the amount and nature of these extraneous substances originally present in the rubber.
After extraction with acetone and vulcanization with the assistance of Accelerator A, Samples 408 and 444 were both found t o have approximately (slightly higher) the same sulfur coefficients as were obtained with the unextracted rubbers, which have already been shown to be almost equal t o each other. The “PORCELAIN” WHITE LEAD extracted samples which were vulcanized with the By Edwin Euston assistance of extra light magnesia, however, gave enELISTON PROCESSCOMPANY, SCRANTON, PA tirely different results. Although the unextracted Received June 10, 1920 samples had sulfur coefficients of 1.874 and 3.132, I n the stack process of corrosion for the manufacture respectively, the same mixtures, when prepared with acetone-extracted rubbers, had approximately the of white lead, two extreme results are noticed. Under properly balanced stack conditions the product is a same sulfur coefficient, 1.3. dense “porcelain-like” crust, approximately zPbCOa Pb(OH)Z, but under less controlled conditions, such as occasionally exist in the top layer of a stack, the product is a light, fluffy powder, approximating PbC03. T h e characteristic appearance of the dense product has been assumed1 as evidence t h a t white lead is a definite compound, 2PbC03.Pb(OH)2, but this assumption‘ does not account for the lack of coherence of the other compound. An explanation is found in the relative cementing effect of the residual colloidal basic lead acetate in t h e “porcelain-like” crust, and of the residual normal lead PIC. 2 acetate in the fluffy product. Probably because of It would appear that Sample 444 differedfrom Sample the coarseness of particles, samples of commercial pulverized white lead, treated, respectively, with basic 408 quite markedly in the nature or condition of its acetone-extractable components. Although we and slightly acid solutions of lead acetate and dried, recognize that the extraction with acetone may not do not demonstrate this difference in cementing effect: be without effect upon the rubber or upon the ex- but the precipitation process for the manufacture of traneous substances left in the rubber, i t would appear white lead affords full opportunity for the pseparation that, if the acetone-soluble substances are removed, of 2PbCOs.Pb(OH)t or PbC03 in very much smaller not only is the response of the two rubbers t o the particles than the dried pulverized product. The accelerating influence of extra light magnesia de- cementing effect is then clearly shown, as the settled creased in both instances, but also the excess sulfur or filter-pressed 2PbC03.Pb(OH)2, when dried without coefficients obtained are small and almost equal. previous washing, forms a hard “porcelain-Iike” mass extremely difficult t o pulverize, the degree of hardness 1 It was obvious that the physical properties of the control mixture being proportional t o the concentration of the basic and the mixture which contained magnesia were very inferior to similar mixtures of unextracted rubber. This was not true, however, for the mixlead acetate; but, when thoroughly washed before
ture which contained Accelerator A; the physical properties of this mixture were good and not greatly below a similar mixture prepared from unextracted rubber
1 Pp. 360, 361, and 364 of “Manual of Industrial Chemistry,” edited a y Allen Rogers. D Van Nostrand Co., 1920.
Oct., 1920
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
drying, forms a powder on slight pressure with the fingers. The P b C 0 3 when dried without previous washing forms a cake noticeably softer t h a n the unwashed z P ~ C O ~ . P ~ ( O Hand ) ~ , when thoroughly washed before drying readily forms a powder a t a slight pressure. The particles. of white lead when originally formed in the stack process are precipitates of fineness comparable t o those of the precipitation process. The hardness of “porcelain” lead, therefore, is due not t o its being an assumed definite compound, z P ~ C O ~ . P ~ ( O but H ) ~t o, the cementing effect of the colloidal basic lead acetate present during formation of the crust. UTILIZATION OF KID, RABBIT, HORSE, AND SEAL MEATS AS FOOD12 13y Arthur D. Holmes and Harry J. Deuel, Jr. OFFICEOF HOMEECONOMICS, U S DEPARTMENT OF AGRICULTURE, WASHINGTON, D. C. Received May 12, 1920
The war emergency food situation led t o a revaluation of foods with respect t o nutritive value and use, including many which were not commonly known in the United States. This was true of meat products as well. as of fats, cereal products, and other food staples. The present experi-ments supply data regarding the digestibility of kid, rabbit, horse, and seal meats. Rabbit, both wild and domesticated, is a well-known food, used t o considerable extent in some localities, particularly when the wild rabbit is in season. Kid is used in some localities in the United States, and horse meat is sold in some markets, particularly in large cities-a necessary requirement being t h a t it be properly labeled. On the other hand, seal meat is unfamiliar t o mcst Americans, although i t is very commonly used as a food in t h e Pribilof Islands, t h e seat of the gsvernment seal fisheries. Although these meats are used only in a limited way in this country and its island possessions, large quantities could be made available for human consumption if there should be a demand for them. EXPERIMENTAL PART
The methods followed in these experiments were essentially the same as those in previous ones of a similar nature conducted by this ~ f f i c e . ~The most satisfactory method of cooking the meat for this purpose was found t o be in the form of small cakes, because this gave a uniform product t h a t was easily sampled by cutting small sectors out of representative cakes. Very little difference in taste was noted in the cakes prepared from the different meats. The purpose of these experiments was t o determine the digestibility of the meat proteins, and the basal diet was so chosen as t o supply a minimum of this food constituent. It consisted of bread, butter, fruit (orange), and sugar, with tea or coffee, j f desired. Yourig men, 2 0 t o 40 years of age, students of a Prepared under the direction of C F Langworthy, Chief of the Office of Home Economics 2 Published with permission of the Secretary of Agriculture a U S Dept Agr , Bullelrn 310 (1915); J . Agr. Res., 6 (19161, No. 16 I b z d , 6 (1916), No 17, U. S Dept Agr , Bulletzn 649 (1918), 717 (1918), 7 6 1 (1919): 781 (1919). 1
975
local university, were selected as subjects, the makeup of the group varying somewhat during the different tests. All the men who took part in the experiment were familiar with this kind of work and were regarded as thoroughly truscworthy. So far as could be judged, all were in good health, of normal appetites, and fairly typical examples of normal young men in the prime of life. The results of analyses of the meats studied are summarized in Table I . As is evident from these figures, the several kinds of meat are similar in composition t o others used as food. TABLEI-COMPOSITION
OF
EDIBLEPORTION AND
KIND Water OB Per MEAT cent Kid 57.8 Rabbit 6 7 . 9 ,... Horse Sen1
Oh’
SEAL MEATS
KID, RABBIT,HORSE
----COOKED
-UNCOOKE-
CarboFuel CarboFuel ProhyValue ProhyValue tein Fat drate Ash per Water tein Fat drate Ash per Per Per Per Per Pound Per Per Per Per Per Pound cent cent cent cent Cal. cent cent cent cent rent Cal. 1 7 . 6 26.1 0 . 9 1342 4 4 . 8 3 8 . 8 1 1 . 5 3 . 8 1175 2 . 4 1330 2 5 . 6 4 . 3 . . 2 . 1 641 4 9 . 4 2 8 . 1 20 1 , . . . . . . . . , . . . 6 4 . 5 2 8 . 6 4 . 1 1.3l 1.5 7 1 1
..
... ...
.
shoulder (corned) . . . . . . . . 1 Glycogen.
....
..
,..
, . . .
62.3 3 0 . 0 3 . 1
....
4.6
671
KID MEAT-The use of goat meat as a food is very old, and kid flesh has long been recognized as a desirable food by many races. However, contrasted with the results of studies by Sherman and Lohnes,’ Bosworth and Van Slyke,2 Jordan and Smith,3 Hall,4 and t o determine the dietetic value of goat’s milk or some of its constituents, one finds in the literature little experimental evidence concerning the nutritive value of goat and kid flesh. I n this count r y this is due, a t least in part, t o the relatively small consumption of these foods, which is largely limited t o those of foreign birth or food habits. Since it seems t o be generally conceded t h a t kid meat .is preferable t o goat meat, just as lamb is preferred t o mutton, the digestibility of the flesh of a young animal was studied, such meat being obtained through the cooperation of the Bureau of Animal Industry. The entire fleshy portion of one-half of the carcass of a 6-month-old kid was removed from the bones, passed through a meat chopper, seasoned, thoroughly mixed, fried in the form of small cakes in a pan greased with a little lard, and served as a part of a simple mixed diet, in such quantity t h a t i t supplied the major part of the protein eaten. The coefficients of digestibility for the entire ration, which on the average supplied 108 g. of protein, I I I g. of fat, 347 g. of carbohydrate, and 2,820 cal. of energy daily, were found t o be 91.7 per cent for protein, 95.5 for fat, and 98.6 for carbohydrate. These values are in close agreement with .those reported for the digestibility of the ordinary simple mixed diet, which are 9 2 per cent for protein, 9 j for fat, and 9 7 for carbohydrate.6 The digestibility of kid meat protein alone was estimated t o be 94.4 per cent.
J . Am. M e d . Assoc., 62 (1914). 1806. N.Y .State Agricultural Experiment Station, Techn. Bulletin 46 (1915), 3 ; J . B i d . Chem., 24 (1916), 173-175, 177-185, 187-189. 3 N. Y . State Agricultural Experiment Station, Bzdlelin 429 (1917), 4 I b i d . , 419 (1917), 7 , Pop. Ed. 6 J . Biol. Chem., 3.9 (1918), 392. 6 Connecticut Storrs Station, Reborl 1901, 245. 1 2
