C91 On the Affinities of 



Experiment XVII. 

 I took a piece of Kilkenny marble which weighed 875 grs. 

 After proper distillation I found it to weigh - 528 



•Lost of carbonic acid, and probably a little water, 



equal to 39*65 per cent. - - . 347 



The colour of the lime thus obtained was very superior in 

 whiteness and apparent purity to that obtained from chalk. 

 50 grains of it fused per se yielded a beautiful transparent 

 amber-coloured glass, free from any metallic appearance. 

 When compared with No. X, which was the fusion of 

 burnt chalk, it differed very materially. The emerald co- 

 lour, so marked there, was replaced by a yellowish fiery tint 

 approaching to the blaze of the Brasilian topaz : neither did 

 it in the least resemble the glasses obtained with the refract- 

 ing spar. No. I, II, and IV. 



Experiment XVIII. 



Kilkenny marble, roasted - 50 grs. 

 Lamp carbon l-50th - - 1 



A perfect glass was obtained by the fusion of this mix- 

 ture of a lead colour, and similar to Experiments No. Ill, V, 

 IX, XI, XII, XIII, and XVI. Of revived iron there was 

 obtained 1| grain. A few flakes of carbon remained upon 

 the surface of the glass, but so small in quantity that they 

 could not soon be csiimaled. It would appear, therefore, that 

 l-50th only of carbon disappears with deacificd Kilkenny 

 carbonate ; whereas with chalk, in the same state, 1 -33d part 

 of carbon was absorbed. Less iron is revived in the expe- 

 riments made with the former than with the latter; which 

 most probably will account for the difference of the quantity 

 of carbon. 



Experiment XIX — iviih pure Lime. 



I dissolved chalk in distilled vinegar, from which it was 

 precipitated by carbonate of ammonia. The precipitate was 

 dried, and possessed a very fine blueish whitish colour. It 

 was afterwards heated to redness to drive oiF the acid, by 

 which its colour was a little tarnished. 



Twenty grains of it was exposed in a heat of 170" of 

 Wcdgewood in a Cornwall clay crucible. When cold, and 

 examined, I found it resolved into a very delicate transparent 

 glass of a deep watery colour, slightly teinted with sea green. 

 This experinient was again repeated with a heat of 158°, 

 and a purer and more delicate glass obtained, though when 

 held to thj light a tinge of green was perceptible. I then 

 apprehended that the acid had dissolved a portion of the iron 



contained 



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