DR. H. DEBUS ON THE CHEMICAL THEORY OF GUNPOWDER. 
583 
This is the equation of a line perpendicular to the side BO. For an appropriate 
value of c it becomes : 
2 y— “2+40 
and then represents the line D W in the figure. 
Mixtures, the composition of which can be represented by the points of such a line, 
will generate by their combustion very nearly the same amount of heat. A powder 
composed of 16KNO 3 +20C corresponds to the point D, and one consisting of 
16KN0 3 +14'4C+11'25S to the point W. The first generates according to equation 
(X.) 1,488,654, and the second 1,484,569 units of heat, two numbers which differ only 
by O'27 per cent., and may therefore be considered identical for practical purposes. 
A line drawn through the point It, perpendicular to the side B C, intersects the 
latter in the point y=13'25, 2=10'6; hence two powders composed of 
16KNO s +16C+5S 
and 16KNO a +13-25C+10-6S 
will generate by their combustion the same, or more correctly, nearly the same amount 
of heat. 
Consequently, if we know the heat of combustion of all the mixtures represented by 
the coordinates of the points of the line B C, then we know likewise the heat of com¬ 
bustion of all the mixtures the composition of which is represented by any point 
within the triangle. And we arrive at the same conclusion with regard to the amount 
of gas which a mixture can produce, the composition of which is represented by any 
point inside the triangle BCD. According to equation (X.) the heat of combustion 
reaches its maximum when y and 2 assume their smallest values, and, on the other 
hand, when y and 2 are greatest the heat of combustion will be a minimum. There¬ 
fore, an inspection of the triangle B D C teaches that of all the infinite number of 
mixtures of saltpetre, carbon, and sulphur which can be transformed according to 
equation (XIII.), the one which is composed of 
16KNO s +8C+8S 
will produce by its combustion the greatest, and the one composed of 
16KNO s + 24C+16S 
the smallest quantity of heat: the first is represented by point B, the second by point 
C of the figure. 
Further, it follows from equation (IX.) that the first of the above mixtures will form 
the smallest, and the second the largest quantity of gas. 
If then we place ourselves at the point B of line B C, to which corresponds the 
generation of the greatest quantity of heat and that of the smallest quantity of gas, 
MDCCCLXXX1I. 4 F 
