320 Intelligence and Miscellaneous Articles. 



The precautions required to be taken to avoid errors of different 

 kinds were fully described, and drawings of the apparatus used ex- 

 hibited, together with a most elaborate and complete set of tables 

 embodying the whole of the results. 



LIV. Intelligence and Miscellaneous Articles. 



BICHLORIDE OF HYDROGEN. 

 r | 1 HIS compound, which contains one proportion of chlorine more 

 -■• than exists in hydrochloric acid, may be obtained, according to M. 

 Millon, by slowly and gradually projecting binoxide of lead into con- 

 centrated hydrochloric acid, surrounded by a cooling mixture of ice 

 and salt. In the reaction which occurs under these circumstances, 

 the liquor produced assumes a deep yellow colour, without any sen- 

 sible disengagement of chlorine, and an abundance of protochloride 

 [of lead] is formed. 



The bichloride of hydrogen, which gives the liquor its colour and 

 properties, has not yet been separated from the medium in which it 

 is dissolved. This compound possesses but little stability, for, at 

 common temperatures, it continues to evolve chlorine during several 

 days. Mercury decomposes it by absorbing part of the chlorine, 

 and thus causing the reproduction of hydrochloric acid. Its compo- 

 sition would appear to be 1 equivalent of hydrogen -f- 2 equiva- 

 lents of chlorine = H Ch' 2 . 



This bichloride would be formed by the reaction of 3 equivalents 

 of hydrochloric acid, or 1 equivalent of binoxide of lead, as shown 

 by the annexed equation : 



3 H Ch, + Pb O 2 = Pb Ch + 2 H O, + H Ch 2 . 



Journal de Chim. Me'dicale, Juillet 1842. 





ON THE ACTION OF CHLORIDES UPON PROTOCHLORIDE OF MER- 

 CURY. BY M. MIALHE. 



M. Mialhe remarks that Capelle, in 1763, first observed the dan- 

 ger arising from a mixture of calomel and sal-ammoniac ; Proust after- 

 wards proved the conversion of calomel into corrosive sublimate by 

 the action of the alkaline chlorides. After mentioning other au- 

 thors, M. Mialhe refers to a note of. his own contained in the Jour- 

 nal de Pharmacie for February 1840, in which he details experiments 

 proving, — 1st, that calomel acted upon by the alkaline chlorides al- 

 ways yields more or less corrosive sublimate ; 2ndly, that it is to 

 this partial conversion calomel owes its medicinal powers; and he 

 afterwards mentions different authors who have confirmed his opi- 

 nions. 



M. Mialhe then relates various experiments which he has since 

 performed to determine the proportion of corrosive sublimate result- 

 ing, under certain conditions, from this action. 



Experiment I. — 1000* parts of distilled water, GO of common salt, 

 60 of sal-ammoniac, and 60 of calomel (<l la vapeur) which had been 



* We have reduced the French weights of the original to parts. 



