Printing of Woven Fabrics. 303 
product which is also liquid, the highest temperature 
resulting from the mixture is generally smaller than the 
temperature @ which contraction could give if the liquid 
disengaged all the heat corresponding to this contraction. 
2. Hence the quantity of heat disengaged in these kinds 
of combinations or solutions is always less than the heat of 
contraction. 
It follows that, in all the cases which I adduce, the mere 
phenomenon of contraction is sufficient to explain the 
development of heat in chemical combinations. Hence 
part of the heat which contraction disengages becomes 
latent in the new compound, and then plays an important 
part, which I shall afterwards point out. 
This quantity of heat, which is latent, or lost to the 
thermometer, may be expressed by a very simple fraction 
of the heat of contraction, if one assume that the specific 
heat is invariable between the temperature O and @, which 
is never the case unless @ is NERY small. Onthis hypothesis 
it becomes 
ti 
1 ge 
Considering one and the same liquid, we may, in conse- 
quence of the errors introduced by delicate and numerous 
determinations, suppose the temperatures to be proportional 
to the vres vive, or to the square of the velocities in the 
molecules, the movement of which produces heat. The 
number 7 represents, then, the fraction of this ws wva 
which has not been expended at the moment of. the 
combination or of the solution. It is, if we like, the 
fraction of the heat of contraction which has remained 
latent in the product of reaction, and 7 is positive. 
(To be continued.) 
PRINTING OF WOVEN FABRICS. 
OPULAR apprehension usually confines the applica- 
tion of the “art preservative” to the multiplication of 
books, newspapers, or other periodicals, and the permanence 
of ideas which, spoken only, would be evanescent and die 
with their originator or his contemporaries. But, although 
the preservation of ideas belongs mainly to that adaptation 
