506 



SCIENCE 



[N. S. Vol. L. No. 1300 



, The stability of tetryl: C. L. Knowles. The 

 following is an outline of the paper: Historical, 

 general methods of preparation; general methods 

 of purification; properties; most common impuri- 

 ties; causes of instability in tetryl; methods of 

 testing stability of tetryl; action of sodium car- 

 bonate on tetryl; detection of sodium pierate in 

 tetryl; effect of sodium pierate on stability of 

 tetryl; conclusions; references. 



The manufacture of trinitroxylene : John Mar- 

 shall. The paper included the following: Dis- 

 cussion of preliminary experiments on the pro- 

 duction of TNX; a study of the properties of a 

 mixture of TNX and TNT when cast together; 

 a discussion of the fraction of xylene best adapted 

 to the production of TNX for ex].)losive shell fill- 

 ing. The methd of nitrating; the nitration of 

 pure metSi-xylene ; the composition of the mixed 

 acid; the study of raw materials with particular 

 reference to the rectification of solvent naphtha 

 and the results obtained from the various ranges 

 of the xylene fraction; the relative suitability of 

 coke oven and water gas tar xylenes. 



The preparation of hexanitro-diphenylamine aiid 

 its use as a booster for shell charges: John Mar- 

 Shall. The following is an outline of the paper: 

 Historical; the preparation of dinitrodiphenyla- 

 mine; preparation of tetranitrodiphenylamine ; ni- 

 tration of tetranitrodiphenylamine to hexanitro- 

 diphenylamine ; preparation of hexanitrodiphenyl- 

 amine by complete nitration of dinitrophenylamine 

 with mixed acid; the neutralization of free acid 

 in hexanitrodiphenylamine ; the explosive proper- 

 ties of hexanitrodiphenylamine; sensitiveness of 

 hexanitrodiphenylamine to detonation; sensitive- 

 ness to impact; sensitiveness to friction; rifle 

 buUet test; explosive power of hexanitrodiphenyl- 

 amine; effect as a booster; conclusions. 



The composition of sponges: F. P. Dunnington. 

 The common sjjonge, used in washing, grows in 

 some warmer ocean waters and consists of a net- 

 work of fiber-like material which is somewhat re- 

 lated in composition to silk fiber. Sponge has 

 long been known to contain the somewhat rare ele- 

 ment iodine, and occasionally bromine is men- 

 tioned as occurring with it; but little has been 

 published about it that is definite. The author 

 proposed to determine the exact amounts of iodine, 

 bromine and chlorine in some sponges from differ- 

 ent sources, and specimens from Florida, Cuba and 

 Bahama Islands were analyzed. The amounts of 

 these elements in these specimens differ greatly, 

 but the average percentages for the four specimens 



examined are, viz.: iodine, .603; bromine, 1.307; 

 ehlorine, 1.06. When we consider the very small 

 amount of bromine and the minute trace of iodine 

 found in the water of the ocean, it is indeed re- 

 markable that these animal organisms can thus 

 select and collect them from the large portion of 

 ehlorine in the salt found there. We also note in 

 this an explanation of the fact that these sponges 

 can only grow in ' ' open ocean water. ' ' 



Quantitative determination of potassium as 

 bitartrate: Sigmund Waldbott and Fred. W. 

 Weissmann. This method was evolved in order 

 to avoid the use of the expensive and difficultly 

 accessible platinum chloride. It is applicable to 

 mixtures of K- and Na-salts resulting from the 

 regular analytical separation of other metals in- 

 cluding Ca and Mg. Principle of procedure: To 

 the neutral solution of K- and Na-salts add Na- 

 bitartrate in slight excess, evaporate to dryness, 

 displace the water-soluble salts by means of water 

 saturated with cream of tartar at or slightly below 

 the temperature of the laboratory, then judiciously 

 displace the cream of tartar solution by the care- 

 ful addition of alcohol. A straight calcium chlor- 

 ide tube containing a plug of cotton is useful in 

 these operations. Finally heat to 100° C. for 1 

 hour in a current of air, cool and weigh. Fair 

 uniformity of temperature is essential for the 

 accuracy of the method. 



. The properties of pyroxylin plastics: E. P. Cal- 

 vert and J. H. Clewell. 



. The extraction/ of potash salts from Tcelp char- 

 coal: J. W. Turrentine, p. S. Shoaff and G. S. 

 Spencer. The charcoal yielded by the destructive 

 distillation of dried kelp is porous and readily yields 

 its values, potassium and sodium chlorides and io- 

 dides when treated with hot water. In order to ob- 

 tain a highly concentrated solution and at the same 

 time efficient extraction, some counter-current sys- 

 tem was found to be necessary. A solution of the 

 problem was found in the adoption of a number of 

 mechanical filter presses connected in series with 

 each other and with leaching troughs interposed. 

 The brine from one press is pumped into the leach- 

 ing trough of the preceding one, while the press-cake 

 from each press falls into the leaching trough of 

 the succeeding one. Thus the brine is pumped up 

 hill while the charcoal passes downward by grav- 

 ity. The two streams passing in opposite directions 

 counter-current extraction results. Filter presses 

 of the revolving disk type and known as the Amer- 

 ican are employed. Filtration and washing are 

 effected iinder vacuum and the press cake is 

 broken loose by compressed air. The apparatus 



