202 



Capt. Noble and F. A. Abel. [Mar. 4, 



and the present note), the residue furnished by special experi- 

 ments with P., R.L.Gr., and E.G. powders, exploded under the usual 

 conditions obtaining in our researches, and in quantities ranging 

 from 4,200 to 35,000 grs. (272*2 grms. and 2,268 grms.). The fol- 

 lowing is a tabulated statement of the results obtained by the two 

 modes of treatment, and of the differences between the proportions of 

 hyposulphite obtained by treatment of portions of one and the same 

 residue with the two different reagents under conditions as nearly- 

 alike as possible : — 



Table I. 



No. of 

 experi- 

 ment. 



Description 

 of powder. 



Quantity used. 



Density 



of 

 charge. 



Amount of hyposulphite 

 furnished by 100 parts of 

 powder with employment 

 of— 



Grains. 



Grams. 



Zinc 

 chloride. 



Copper 

 oxide. 



Differ- 

 ence. 



245 



P. 



3,396 



220 -05 



0-3 



•12 



1-93 



1 -81 



241 



P. 



5,660 



366-76 



0-5 



•07 



2-46 



2-39 



246 



R.L.Gr. 



4,200 



272-16 



0-4 



•05 



1-43 



1-38 



244 



E.L.G. 



5,250 



340 -19 



0-5 



•06 



1 -58 



1-52 



243 



F.G. 



4,523 



293 -41 



0-4 



•07 



1-56 



1-49 



242 



F.G. 



6,300 



408 -23 



0-6 



•27 



2-26 



1-99 



247 



P. 



35,000 



2,267 -97 



0-23 



•78 



2-82 



2-04 







(5 lb.) 











For purposes of comparison, we subjoin a statement of the lowest 

 proportions of hyposulphite furnished by 100 parts of the three 

 powders used in our general series, and also the proportions, similarly- 

 expressed, which were obtained in the experiments with sporting and 

 mining powder, the residues of which were dissolved with the same 

 special precautions adopted in the case of the experiments given in 

 Table I. 



Table II. 



Number of 

 experiment. 



Nature of powder. 



Amount of 

 hyposulphite 

 in 100 parts 

 of gunpowder 

 used. 



Remarks. 



7 

 44 

 17 



196 

 194 



Pebble. 

 R.L.G. 

 E.G. 



Curtis & Harvey No. 6. 

 Mining powder. 



2- 06 



1- 75 



3- 04 



2- 28 

 2-77 



[" Lowest proportions 

 ■I furnished by the re- 

 [ spective powders, 

 f Special precautions 

 < taken in collecting 

 [ the residue. 



