in the Compounds of Zinc and Antimony. 227 
mony in the alloy, as is the case with Sb Zns, then the curve of 
variation would be the straight line formed by the continuation 
of the line a 6. From this line 6h the course of the curve is 
deflected by the force which determines the union of the ele- 
ments in definite proportions, and which for the want of a spe- 
cial term, I will call the Chemical Force. This is so strong that 
the curve runs parallel to the axis of ordinates through the dis- 
tance km. Beyond this point, the influence of the excess of an- 
timony in the alloy becomes stronger than the chemical force, and 
the curve gradually bends towards the line hb which it finally 
meets at h. In the portion hv of the curve, the analyses are best 
represented by the are of a circle, of. which the radius equals h e 
or one-half of A 6, and to which the line Am is tangent. In the 
portion 2 m the points determined by analysis may also be con- 
nected by the arc of a circle of which the radius o’ n equals the dif- 
ference between the radius 0” and twice gn, so that the two cen- 
tres are at the same distance from the line ak. The whole curve 
is evidently the result of two forces; one acting along the chord in 
the direction b h, a force tending to increase the amount of anti- 
Stead of extending to e, changes frog# this directi k, and after- 
fluence of Sb Zns as suggested above, the reason of this difference 
between Sb Zn2 and Sb Zns in this respect is not clear; but as 
Some evidence that it is not accidental it may be stated, that the 
distance & ¢ equals c#, the last point being the one, at which the 
tangent line mk extended meets the curve. Another remark- 
of the curve of Sb Zne from the line a h, viz. kd, mf, and ng, 
ay simple multiples of the first; ng is twice and m / three times 
