FOR DISTINGUISHING SACCHARINE JUICES. 597 



of others or leads to their prediclion, since it has a tendency to confound 

 two very different bodies, a)id since on the other hand it establishes a 

 difference between two bodies lohich in other respects have the greatest 

 analogy of properties and composition. 



It does not therefore fulfill the conditions \Sb c d. 



21. From the manner in which M. Biot has related his observations, 

 it appears to me that, in the actual state of things, the property of caus- 

 ifig a deviation in the plane of polarized light is in its variations con- 

 nected rather with the various arrangements that the particles of a species 

 may take without their nature being altered, than it is with the various ar- 

 rangements which constitute different species ; so that there is not now 

 more reaso7i to establish a mutual relation between species which act in 

 tlie same direction and with the same energy, than there is to presume 

 that a decided opposition exists between the properties of two species 

 which act differently upon the plane of polarization. 



§2. 

 On die probable Utility of the Optical Character. 



22. I have stated the objections which may be urged against the use 

 of the optical character as it has been presented by its author ; I shall 

 now consider in what it is likely to be useful. By this mode of examining 

 the physical character, the application of which to organic chemistry 

 has been proposed, I hope to render apparent the object which I 

 have really in view, which is to restrain within its true limits that which 

 has been made to exceed them by ascribing to it a generality which 

 it does not possess, and a degree of precision which it can only attain 

 by ulterior experiments, and which even then will be confined to the 

 limits which I attribute to it. 



Article I. — Utility of the Optical Character for the various Ar- 

 rangements of the Atoms or Particles of a Species. 



23. If it be true, as M. Biot thinks, that a body, as grape sugar, 

 though dissolved in crater, affects the molecular state in such a man- 

 ner as to cause deviation to the right or left of the plane of polarization, 

 accordingly as the solution has been made with crystallized sugar, or is 

 such as nature presents us with in the juice which has just been ex- 

 tracted from the grape, it is undoubtedly interesting to inquire whether 

 other species of immediate principles present an analogous phsenome- 

 non, in order to judge whether any consequence may be deduced, re- 

 lative either to the various arrangements of which the atoms or parti- 

 cles of these species taken separately may be susceptible, or to the 

 cause which produces the variation of the phaenomenon. 



2*. When the t>bject of study is a species of body brought to its 

 2s 2 



