IN STUDYING QUESTIONS OF CHEMICAL MECHANICS. 339 
tion of crystallizable sugar it might contain, and to see whether 
it was associated with other non-intervertible sugars, but gifted 
with the rotatory power towards the right or towards the left, 
which would have been modified during the operation*. I 
found that in fact a considerable portion of the primitive sugar 
had remained unaltered, for it amounted to 0°92 of the weight 
of the total mass of the sample examined. But the remainder 
of the mass with which it was associated was deprived of rota- 
tory power. This last result agrees with an experiment of 
M. Mitscherlich, by which this philosopher ascertained that 
cane-sugar, heated to 160° in a bath of chloride of zinc, is trans- 
formed into an inactive body, at the same time preserving its 
transparency. This undoubtedly is the modified portion of the 
total mass, which, interposing itself between what remains of the 
crystallizable molecules, and solidifying with them by the effect 
of quick cooling, hinders them from grouping in crystals of 
sensible dimension, and allows the resultant of their individual 
molecular powers to be perceived. This resultant will therefore 
be the greater the less the heat employed, which was the case 
with the experiment which I have mentioned; for it had been 
arrested as nearly as possible at the term necessary to obtain 
non-crystallized diaphanous plates. But it will be conceived that 
a more lively or longer continued action, by neutralizing a greater 
proportion of the sugar employed, should give masses possessing 
a less rotatory power; this was the case in the first experiment 
above related. For, on applying the same principle, and consi- 
dering the mass then obtained as composed of unaltered crystal- 
lizable sugar, associated with a neutral system, we find that the 
ponderable proportion of this sugar, calculated from the aqueous 
solution, was only 0°81 f. 
* The detail of this process, as well as the formule necessary for its appli- 
cation, have been given in the Comptes Rendus de l Académie des Sciences, 
tome xv. pages 528, 534, 697 et seg. ‘The reader may also see in the same 
collection, tome xvi. p. 619, the manner of employing them for the quantitative 
analysis of the solid or liquid mixtures in which crystallizable cane-sugar is 
associated with other non-crystallizable sugars. The progressive course of the 
inversion produced by various acids has been considered comparatively in tome 
xvii. p. 755. The effects are there described which they produce according to 
their nature, the proportion employed, the temperature, and the time during 
which they are allowed to act. 
+ This is seen from the formule established in the Comptes Rendus de 
P Académie des Sciences, tome xvi. pp. 619 et seg. Let x be the ponderable 
proportion of crystallizable cane-sugar contained in a solid mass, composed of 
this sugar associated with other non-intervertible sugars, exercising the rotation 
towards the right or the left, and with any system of inactive bodies. A certain 
weight, p, of this mass is dissolved in a known weight, e, of distilled water, 
