[ 545 ] 
charge, p. 272. Mr. Robins’s opinion with refpeft to the manner in which -guti* 
powder takes fire, ibid. Table of experiments firewing that effedl, p. 274. In the 
formation of fire-arms no regard is to be had to any fuppofed advantages from par- 
ticular fituations for the vent, p. 277. The belt form for the bottom of the bore, 
and the fituation of the vent, in great guns and fire-arms, p. 279. New method of 
determining the velocities of bullets, ibid. The momentum of a gun mull be pre- 
cifely equal to the momentum of its charge, ibid. Method of determining the 
velocity of bullets, p. 280. Another fimpler and eafier method of determining that 
%’elocity, p. 282. Table filewing the refult of experiments in thofe methods, p. 
287. Table {hewing how thofe methods agreed upon the whole, p. 289. Compa- 
rifon of the two methods, p. 292. Of a very accurate method of proving gun- 
powder, p. 298. All the cprouvettes, or powder-triers, in common ufe are defec- 
tive in many refpecb, ibid. Powder may anfwer to the proof commonly required, 
and yet turn out very indifferent when ufed in fervice, ibid. The abovementioned 
method of proving gun-powder explained, p. 299. The apparatus defcribed, p. 
300. The temperature of the atmofphere has a very fenfible effect upon the force 
of gun-powder, p. 302. Of the comparative goodnefs or value of powder of dif- 
ferent degrees of firength, p. 303. Of the relation of the velocities of bullets to 
their weights, p. 305. Mr. Robin’s theory defective, ibid. Figure explaining the 
relation of the velocity to the weight, p. 309. Table of the quantity of powder 
inflamed in feveral experiments, p.312, Obfervadons on the weight of gun-pow- 
der, p. 314. Different forts of powder mentioned by French authors, ibid. The 
weakefl powder, or the heaviefl: in proportion to its elaftic force, ought to be ufed to 
impel the heaviefl: bullet, p. 315. An objection to that pofition anfwered, ibid. 
Table of the relation of the velocities of bullets to their weights, fuppoiing their 
velocities to be in the reciprocal fub-triplicate ratio of their weights, p. 316. Table 
of experiments with half the weight of the powder added to the weight of the bul- 
lets, p. 317. Table of the refult of thefe experiments, p. 319. Of an attempt to 
determine the explofive force of aurum fulminans, or a comparifon between its force 
and that of gun-powder, p. 321. Defcription of a barrel provided on purpofe for 
that experiment, ibid. Refult of that experiment, p. 322. Of the fpecific gravity 
of gun-powder, p. 323. Mifcellaneous experiments, p. 324. Of fome unfuccefsful 
attempts to increafe the force of gun-powder, ibid. Account of an experiment to 
try the force of water rarified into fleam in impelling bullets, ibid. Refult of that 
experiment, p» 323. Refult of others made with highly redlified fpirits of wine, 
etherial oil of turpentine, and fmall quantities of quicknlver, inftead of water, ibid, 
With rethiops mineral intimately mixed with gun-powder, p. 326. Ingredients of 
Common pulvis fulminans, ibid. Relult of an experiment made by mixing fast of 
tartar with gun-powder, p. 327. With fal ammoniacum, ibid. With brafs duff:, 
ibid. Earthy particles and all kinds of impurities are very detrimental to gun- 
powder, and why, p. 328. Of an attempt to fhoot flame inftead of bullets, ibid. 
See Brafs Ordnance , Battle Powder,, , . 
7 4 B 2 TekJatfij 
