1813.] different Hays which compose the Solar Light. 1 67 



rnical faculty expressed by another function is at its minimum at 

 the red end, and at its maximum at the violet end, or a little 

 beyond it. This simple supposition, which is only the simple 

 statement of the phenomena, equally agrees with all the facts 

 hitherto observed, and accounts for those established by M. 

 Berard, and even enables us to predict them. In fact, if all the 

 rays, which produce these three orders of phenomena, are rays of 

 light, they mustof course be polarized in passing through Iceland 

 crystal, or in being reflected from a polished glass with a deter- 

 mined incidence : and when they have received these modifica^ 

 tions, they must be reflected by another glass, if it is properly 

 placed, to exert its reflecting: energy on the luminous molecules. 

 On the other hand, if thatTorce is null on the visible luminous 

 molecules, the invisible light will not be any longer reflected : 

 for the cause which occasions or prevents reflection appears to 

 act equally upon all the molecules, whatever their refrangibility 

 may be. It ought, therefore, to act upon the molecules of 

 invisible light, the condition of visibility or invisibility relating 

 merely to our eyes, and not to the nature of the molecules which 

 produce these sensations in us. But though this mode of viewing 

 the facts appears to us the most natural and simple, we cannot 

 but approve the sage reserve of M. Berard in not attempting to 

 decide questions upon which experiment has not yet accurately 

 pronounced. 



The Class heard with pleasure the detail of these interesting 

 experiments, which were presented by the author on the same day 

 that he and M. Delaroche obtained the prize offered for the 

 determination of the specific heat of the gases. We propose 

 to the Class to confirm, by its approbation, this new and valuable 

 set of experiments; and we regard itas very worthy to be printed 

 in the Recueil des Savans Etrangers. 



(Signed) Blkthollet, Chaptal, and Biot, 



Commissioners. 



Article II. 



On the Dftllonian Theory of Definite Proportions in Chemical 

 Compounds. By Thomas Thomson, M.D. F.R.S. 



(Continued from p. 115.) 



I shall continue the table of chemical compounds in this 

 Number a little farther, observing the same method as in the 

 preceding part of this paper. 



4 



