]^2B- ACTION OF HEAT MODxPlEB 



some snnd bfing laid in tliis crucible, the metal was collected! 



on its surface. Oti some occasions, a sounrl ot ebullition \va« 



heard daring the action of heat ; but this was a certain sign 



of failure. 

 Ttesults. The results of the most important of these rxperimenfs, 



liave been reduced to a common standard in the second tabic 



]Uaced in the Appendix ; to which reference is made bv the 



following numbers. 

 T'xnenmprit No. 1. — Ou the l6"tli of June 1803, I made an cxporimcut 



spi'f of abort''" ^""'^^^^ these arrangements. I had tried to use a weight of ;30ib. 

 6001b. ciii rhe producing a pressure of <)0 lb,, but I found this not sufficicrit^ 

 round inch, - , , ' . , „ ^, ,. , , -. ,i i i • i 



Of about 50 at- ■' ""•" """S ^" ^ weight ot 1 cwt,, or 112 11). ; by which * 



nio-phtics. compressing force was apjTlied of 3 cwt. or 336 lb. Very 

 little metal was seen to escape, and' no =ound of ebullition was 

 heard. The chafk in the body of the large tube was reducet'f, 

 to quici;Iime ; but what lay in tlie inner tube was pretty firm, 

 and etTervesced to the last. One or two faceftes, ai good ap- 

 pearance, vvere likewise found. The contents of the smalt 

 tube had lost but ^.6 per cevt. ; but there was a small visible 

 intrusion of metal, and the result, by its appearance, indicated 

 a greater loss. I corisidcred this, however, as one point gained ; 

 that being tiie first tolerable compression accomplished by a 

 determinate force. The pyrometer indicated 52". 



The experiment was repeated the same day, when a still 

 smaller quantity of metal escaped at the muzzle ; but the bar- 

 rel l)ad given way below, in the manner of those that Lave 

 yielded for want of sufficient air. Even this result was satis- 

 factory, by shewing that a mechanical power, capable of forc- 

 ing some of the barrels, could now be commanded. The 

 carbonate in the little tube had lost 20 per cent. ; but part of 

 it was in a hard and firm state, effervescing to the last. 

 >i)iot!iei-expe- No. 2. — On the 21st June, I made an experiment with 

 iiujeut. another barrel, with the same circumstances. J had left an 



empty space in the large tuhc, and had intended to introduce 

 its muzzle downwards, meaning that space to answer as an air- 

 tube ; but it was inverted by mistake, and the tube enteriiTg 

 with its muzzle upwards, the einply space had of course fiUM 

 with metal, and thus the experiment was made without any 

 included air. There was no pyrometer used ; but the heat 

 was guessed to be about 25° where the subject of experiment 



lay. 



