July 28, 1922] 



SCIENCE 



119 



lime proved best, while those which are water 

 soluble as glues are not so satisfactory for exte- 

 riors. Several alkaline salts were used for accel- 

 erating the solution of casein, trisodium phos- 

 phate proving most satisfactory. Among the 

 addition agents used with lime in mixtures con- 

 taining no definite siccative alum and table salt 

 were effective on improving the workability and 

 permanence of the whitewashes. Several formu- 

 las developed and tested are shown to be superior 

 to most of those in common use. 



Can we afford to inaTce potash in Americas' 

 E. NOBBIS Sheeve. Broad economics regarding 

 the manufacture of potassium salts in America 

 and from American raw materials are considered. 

 Cost of materials, labor and freight is discussed 

 and the value of various by-products cheapening 

 the cost of the primary material is treated. Is it 

 worth America's while to pay the cost necessary 

 to finish the development of the potash industry'? 

 Past, present and probably future costs to farm- 

 ers and chemical industry for their potash are 

 described. It will be money in the pockets of 

 American potash consumers to build their own 

 industry here, but the potash industry should be 

 developed regardless of cost for it is necessary 

 to safeguard food and clothing of the country. 



Discontinuous extraction processes: L. F. 

 HawleT. This paper is a study of Turrentine's 

 extraction process^ according to the theory of 

 discontinuous extraction formerly developed.2 By 

 using Turrentine's data in the mathematical 

 tlicory of the process it is shown that the incom- 

 plete extraction is due to the fact that complete 

 solution of the potassium chloride was not ob- 

 tained in the first treatment of the raw material. 

 The other conditions of extraction were so effi- 

 cient that the final recovery was only slightly 

 less than the theoretically perfect recovery with 

 the solvent ratio and number of treatments em- 

 ployed in the process. 



The classification of coal: S. W. Parr. The 

 use of ratios between certain constituents as an 

 index of coal types shows that the value of a 

 ratio depends upon the freedom of the factors 

 employed from adventitious material, or material 

 not essential in producing the type characteristics 

 to be indicated, and shows that the use of analyt- 

 ical factors in the construction of a system of 

 classification based on ratios is limited, for the 

 ratios do not differentiate with respect to vari- 

 ables inherent in the actual coal substance as 



^Jour. Ind. and Eng. Chem., 13, 605 (1921). 

 - Discontinuous Extraction Processes, 9, 866 

 (1917). 



oxygen. This factor is significant as between 

 different types, and its effect should be given a 

 place in any system indicating type distinction. 

 Such a factor may enter into the scheme of classi- 

 fication by using heat values referred to the unit 

 or pure coal substance. Accuracy of the values 

 derived from the author's unit coal formula are 

 shown. 



A comparison of the standard gas furnace and 

 mioropyrometer methods for determining the 

 fusibility of coal ash: A. C. Fieldnee, "W. A. 

 Selvig and W. L. Parker. The micropyrometer 

 method for determining coal ash fusibility is 

 quicker than the gas furnace method and better 

 for the operator. Coal ashes fusing under 2,600° 

 F. by the gas furnace method can usually be 

 checked within 100° F. by the micropyrometer 

 method if fused in a reducing atmosphere of com- 

 bustion gases similar to that employed in the 

 gas furnace method. Very refractory ashes, 

 fusing above 2,800° F. as determined by the gas 

 furnace method, tend to give considerably lower 

 results by the micropyrometer method. The two 

 methods can not therefore be considered as 

 strictly alternate methods for all ashes. The 

 great majority of coal ashes from American coals, 

 however, fuse below 2,800° F. in the gas furnace. 



The calorific value of American woods: S. W. 

 Parr and C. N. Davidson. There are no well 

 authenticated values published in the literature 

 for the calorific value of American woods, and 

 the published values for foreign woods are un- 

 reliable. The values of the time of Berthier and 

 Winkler are about 50 per cent, of those reported 

 by Gottlieb, yet no basis of fair comparison is 

 possible because of the lack of definite informa- 

 tion as to the presence of moisture. The paper 

 reports on a detailed study of the moisture factor 

 in order to base calorific values upon the mois- 

 ture-free material. The heat values were deter- 

 mined by means of a calorimeter, adiabatic in 

 type, using a bomb with platinum lining. 



The shatter and friability tests for metallur- 

 gical coTce: S. P. Kinney and G. St. J. Peerott. 

 A discussion of testing methods, reproducibility 

 of results, and their interpretation. A large 

 amount of test data obtained at the Southern 

 Experiment Station of the Bureau of Mines is 

 used as the basis of the discussion. A compari- 

 son of results of the machine and bag shatter 

 test procedure, an improved method of conducting 

 the bag shatter test, the effect of size of coke on 

 absolute and relative results obtained by the fria- 

 bility or "hardness" test, and the effect of other 

 modifications of the standard procedure are given. 



