322 Intelligence and Miscellaneous Articles. 



These two experiments, repeated with precipitated calomel, gave 

 the following results : — 



1st Experiment. — Sublimate 1*8 part. 



2nd Experiment. — Sublimate 0*6 part. 



Experiments were then made to decide the question, whether the 

 degree of dilution of the alkaline chlorides put into contact with the 

 calomel, had any remarkable influence on the quantity of sublimate 

 produced : this was found to be the case, as indeed theory would 

 indicate. 



It was also proved, by direct experiment, that the presence of 

 neutral organic bodies does not hinder the conversion of calomel 

 into sublimate ; on the contrary, dextrine favours the change; sugar 

 and albumen probably do not modify it ; and lastly, lard and gum- 

 arabic very evidently retard it. 



M. Mialhe remarks, that in his first experiments on the conver- 

 sion of calomel into sublimate, he supposed it to take place by the 

 conversion of 1 equivalent of calomel into 1 equivalent of mercury 

 and 1 of sublimate ; he now finds that the presence or absence of 

 atmospheric air modifies the results. 



1st Experiment. — Without the presence of air. Water 2000 

 parts, common salt and sal-ammoniac of each 120 parts, precipi- 

 tated calomel 60 parts, digested for twenty-four hours in a stopped 

 bottle ; sublimate produced 0"3 part. 



2nd Experiment. — The same substances allowed to react with the 

 presence of the air, yield IT part of sublimate. 



It appears, then, that calomel and the alkaline chlorides, when 

 air is present, produce three times as much sublimate as when they 

 react without it. The explanation of this appears to be, the fact, as 

 stated by M. Guibourt, that calomel absorbs a certain quantity of 

 oxygen at common temperatures ; at a higher temperature the ab- 

 sorption is greater ; and in the case now mentioned, the absorption 

 is accelerated by the presence of the alkaline chlorides. It is not 

 therefore surprising that the proportion of sublimate should be 

 greater when the air is present, since for every equivalent of oxygen 

 absorbed, an equivalent of sublimate is produced ; and moreover 

 each equivalent of binoxide of mercury formed, gives by double de- 

 composition with the alkaline chloride, 1 equivalent of sublimate 

 and 1 of alkaline oxide. 



To check these researches, the following experiments were made : 



1st Experiment. — Water 1000 parts, calomel and hydrochloric 

 acid each 60 parts, digested twenty-four hours at temperatures 

 between 104° and 122° Fahr. ; sublimate produced, without the 

 contact of air, 0*4 part. 



2nd Experiment. — The same substances, reacting with air present, 

 gave T4 part of sublimate. 



It may be concluded from the foregoing, that about two-thirds of 

 the sublimate produced are formed by the influence of oxygen, and 

 that one- third only is derived from the mere and simple conversion 

 of calomel into metallic mercury and calomel. 



M. Mialhe finds also, that calomel may partly be converted into 



