» On the various Combinations of Carbon tvith Oxtgi/i. 



By the time that the retort became red, or rather fooner, gas was produced In great 

 abundance, and continued to come over for two hours or upwards ; this gas was received 

 in different veflels, fo that the portions obtained at different periods of the procefs might 

 be examined feparately: the whole amounted to 150 oz. meafuresXtroy.) 



The firft portion confifted of carbonic acid gas, one part, and inflammable gas four 

 parts. 



The fecond portion pf carbonic acid gas, one part, and inflammable gas five parts. 



The third was exaftly fimilar to the fecond, and then to the end of the procefs; it con- 

 fifted pretty uniformly of carbonic acid gas, one part, and inflammable gas, fix parts. I 

 repeated this experiment, and employed an iron retort, in order that a much greater degree 

 of Jieat might be applied. In this cafe the gafes obtained were exaclly fimilar, and the very 

 laft portion was found to confift of carbonic acid gas one part, and inflammable gas fix 

 parts ; but the quantity in all, although the oxide of iron and charcoal together did not 

 exceed two ounces, was prodigious, and muft have amounted to many gallons, by meafure. 



SufpeiSting that fome of the other metallic oxides might yield fimilar refults, if treated 

 with charcoal in the fame manner; I expofed a quantity of the fublimed oxide of zinc to 

 a red heat for nearly an hpur, and then mixed it with charcoal, which had likewife been 

 previoufly heated ; thefe were introduced into a coated glafs retort, and fubjefted to a heat 

 gradually raifed as in the former experiments ; before the retort became red, a confiderable 

 quantity of gas was difengaged, but upon increafing the heat it came over in torrents. 



The firft portion confifted of carbonic acid gas, and inflammable gas, in the proportion 

 of I to 9. The fecond, of the fame gafes, in the proportion of 1 of the former, to 26 of 

 the latter, and what was received afterwards, was purely inflammable ; the whole 

 amounted to 90 ounce meafures. At the end of the procefs a quantity of metallic zinc 

 was found in the neck of the retort. 



I next fubjefled the red oxide of copper and charcoal to a fimilar procefs, and the quan- 

 tity of gas colle£led from an ounce of this mixture, amounted to 64 ounce meafures. 



The firft portion confifted of the carbonic acid, and inflammable gafes, in the propor- 

 tion of 10 of the former to one of the latter. The fecond of the fame gafes, in the proi- 

 portion of 15 to 55 ; and the third was purely inflammable gas, without any fenfible quan- 

 tity of carbonic acid. At the end of the procefs the copper was found in fmall globules in 

 its metallic ftate, mixed with the charcoal. 



The next fubjeft of experiment was litharge, which was dried as much as poffible, 

 mixed with hot charcoal, then introduced into a coated glafs retort, and expoied to heat 

 in the fame manner as the other mixtures. 



The firft portion of gas confifted of carbonic acid, and inflammable gas very nearly in 

 equal bulks. The fecond, of the fame gafes in the proportion of 13 of the former to 39 

 of the latter, and what came over afterwards was almoft purely inflammable, the whole 

 amounting to about 40 ounces. The lead was found revived and mixed with the charcoal 

 in the form of fmall globules. 



The 



