C/temico-Galva7iic Observations. 129 



Acid was decomposed, and nitrous gas was disengaged. 

 From the sulphuric and muriatic acids hydrogen were 

 evolved. This fossil blackens at a red heat. The carbonic 

 acid was decomposed, and disengaged itself under the form 

 of gaseous oxide of carbon; and the iron became still more 

 oxidated. This metal is found in the carbon ate at the mi- 

 nimum of oxidation, and under the form of white oxide*. 



It would be difficult, considering the concomitant dis- 

 engagement of the other gases, to determine justly what is 

 contained iu the carbonic gas of this carboiwied iron. 



We know that Morecchini has found fluoric acid in fossil 

 elephants' bones. Does not this fact, which is confirmed 

 by Klaproth, lead us to suspect that phosphoric acid trans- 

 forms itself into fluoric acid ? Many appearances come in 

 aid of this suspicion, and, among others, the property of 

 phosphoric acid to corrode glass : the common property of 

 fluates and^jhosphatesof lime to yield a pyrophoric light, &c. 

 The observations made by Gehlen on the occasion of his 

 trials upon aether with fluoric acid, deserve on this account 

 an equal attention. And Klaproth, in analysing the topaz, 

 in which he found 0-05 — 007 parts of fluoric acid, has 

 observed another fact, which is particularly remarkable, 

 viz. that the loss which this fossil undergoes by ignition. 

 is always more considerable in crucibles of lead than of 

 clay j although, after the observations of Guyton on the 

 bad quality of carbons for conducting heat, one would have 

 expected a contrary effect, which appears to indicate that 

 in the former crucibles the topaz undergoes another action 

 than that of fire. 



XXVH. Chemico- Galvanic Observations. By 

 M. Oersted f. 



X HAVE lately discovered a Galvanic phasnomenOn hitherto 

 •unknown. I Was led to it by an experiment of M. Ritter, 

 published some years ago. This philosopher had fouud llidt 



• There is in this department, in the neighbonrhood of Jodogne, a mine of 

 vitriol of iron in great crystalline masses perfectly transparent and colourles:, 

 which, by its appearance, one would take for Glauber's salts. The earth 

 which surrounds this salt consists, in that part of it which ii not in ci^ntact 

 with the air, almost entirely of black oxide of iron. The salt itself, -vvhtii 

 it is dissolved, becomes green by its being exposed tq. the .lir, after which 

 it is precipitated by th^ same alkalis under the ordinary colour, ^ty c«l» 

 league De Roover, who has made me aci^tiinted with this sal(, has received 

 solid masses of it many pounds in weight. — V. M. 



f From Aa« Moia\ Juarnal, vol. vi. 



Vol. 23, No. 90. Nw. 1605. 1 the 



