upon Gun- powder, &c. 29 9 
Board of Ordnance but fuch as has gone through the efta- 
bliihed examination, and has anfwered to the ufual teft of its 
being of the ftandard degree of flrength. 
But though the common powder- triers may fhew powder 
to be better than it really is, they never can make it appear to 
be world than it is; it will therefore 1 always be the intereft of 
thole who manufacture that commodity to adhere to the old 
method of proving it. But the purchafer will find his account 
in having it examined in a method by which its goodnefs may 
be. afcertained with greater precifion. 
Tile method I would recommend is as follows. A quantity 
of powder being provided, which, from any previous exami- 
nation or trial, is known to be of a proper degree of ftrength to 
ferve as a .ftandard for the proof of other powder, a given charge 
of it is to be fired, with a fit bullet, in a barrel fufpended by 
two pendulous rods, according to the method before defcribed, 
and the recoil is to be carefully meafured upon tile ribbom And 
this experiment being repeated’ three or four times;- oroftener if 
th ere is any difference in the recoil, the mean and tire extremes 
of the chords may, be marked upon the ribbon by black lines 
drawn acrofs it, and the word 1 proof maybe written upon the 
middle line-; or if the recoil is uniform (which it will be to a 
fiifhcient degree of ’ accuracy, if care is taken to make the ex- 
periments under the fame circumflances) then the proof mark 
is to be made in that part of the ribbon to which it was con- - 
handy drawn out by the recoil in the different trials. 
The recoil, with a known charge of ftandard powder, being 
thus afcertained and marked upon the ribbon, let an equal 
quantity of any other powder (that is to be proved) be fired iiu 
the fame barrel, with a bullet of the fame weight, and every 
other circumftance alike, and if the ribbon is drawn out as. 
fan 
