Compounds of Fixed Oil and Mdallic Calces. 1 7, 



Has acquired an acrid property from tlie heat it has been fubjefted to. It is probable, 

 tlierefore, that the combination 1 have formed might in feme cafes be advantagcoufly fub- 

 ftitiited for that compound. Geoffroy iontiirly remarked, in the Memoirs of the Academy 

 for 174T, that the combination of oil which he made in the manner of plafters, formed a 

 kind of foap. 



The combination of oil and fiiver is white when firft made ; but after a few inftants' 

 o-pofure to the air, it affumes a red tinge, which no doubt depends on the facility with 

 whicli this metal yields its oxigene to all combullible matters ». The change of colour- 

 in the oleo-mercurial combination appears to me to depend on the fame principle. When 

 tlie combination of fiiver is fufed, its furface becomes covered with a very brilliant iris;- 

 and beneath the fupertlcies it is black. 



The combination of gold and oil partly floats on the mixture in the form of a cream,, 

 which is at firil white, foon after which it affumes a dirty purple colour. It dries with 

 dillicuky, and adheres to the (kin, fo that it is difficult to efface the impreffion. 



I have combined the metallic principle of manganefe by mixing a folution of foap with 

 a folution of manganefe in the marine acid. This combination is at firfl white. It affumes in 

 the air a reddifli colour of peach bloffoms, which becomes more and more deep. It fpeedily 

 dries to a hard brittle fubftance, and by liquefaaion it affumes a brown blackifli colour. 



In order to afcertain whether eflential oil had likewife the property of combining with ■ 

 metallic fubftances,.! mixed a folution of Starkey's foap newly made with a folution of vitriol 

 of copper. The fame thing happened as with the common foap, excepting that the com- 

 bination was rather a lighter green, and more friable. Black foap, which is faid to be made 

 with whale-oil, afforded me, with the folution of vitriol of copper, a combination which, 

 compared with that obtained by means of common foap, is rather of a deeper green, re- 

 mains fomewhat fofter, and poffeffes a very difagreeable fmell. 



I was defirous of forming a foap with cauflic alkali and re£lified animal oil, with the 

 intention of form.ing other combinations afterwards ; but this oil formed no union with alkali. 

 We have feen that the calcareous earth (and it is the fame with ponderous earth) has more. 

 affinity with oil than fixed alkali, and this has more than magnefia; but the combination of 

 magnefia is not decompofed by the cauftic volatile alkali, fo that magnefia follows the fixed 

 alliali in the order of affinity. Afterwards comes the volatile alkali, which decompofes all 

 the metallic combinations with more or lefs facility. It totally diflblves the combination 

 of fiiver ; but the mercurial combination is that which appeared to me moft flrongly to 

 refill decompofition. With regard to clay, its combination is decompofed by the cauflic- 

 volatile alkali, even more readily than the metallic combinations. Whence I infer that 

 it may be placed after the metallic fubilances. 



Oils by expreffion did not appear to diffolve the calcareous and argillaceous combina-- 

 tions ; oil of turpentine diffolved only a fmall portion of the calcareous combination, but 

 rather more of that of clay, with which it formed a jelly. Ardent fpirit diffolves fome 

 of the oleo-metallic combinations without heat. It requires heat to diffolve fome others ■ 



* The learned author will certainly approve my trandating the only theoretical palTage in his memoir accon'.-- 

 ing to the fimpic doflrinc he now maintains. In the original the cffcia is afcribcd to the attraaion of Giver to 

 phlogillon. N. 



but 



