228 Nature of White Precipitate. 



Having inferred from previous experiments that the " white 

 precipitate" was a compound of one proportional of peroxide 

 of mercur}' and one of muriate of ammonia, Mr. Hennell ve- 

 rified his opinion as follows. A solution of one proportional 

 of corrosive sublimate ( = 272) was mixed with a quantity of 

 solution of ammonia, containing two proportionals (17 x 2 = 34) 

 of that alkali ; a neutral mixture resulted, white precipitate was 

 formed, and one proportional of muriate of ammonia (am- 

 monia 17 + muriatic acid 37 = 54 of muriate of ammonia) was 

 found in solution. In this case, the 2 proportionals of chlorine 

 in the sublimate (36 x2 = 72) were converted, at the expense 

 of 2 pz'oportionals of water, into 2 of muriatic acid, which, 

 UTiiting with the ammonia, formed 2 of muriate of ammonia. 

 The 2 proportionals of the oxygen from the water (equivalent 

 to the 2 of hydrogen transferred to the chlorine) united to the 

 1 proportional of mercury in the sublimate, to form 1 of per- 

 oxide of mercury, which fell in combination with 1 of muriate 

 of ammonia to constitute white precipitate ; while the other pro- 

 portional of muriate remained as above stated in solution. The 

 equivalent number, therefore, of white precipitate, is 270, and 

 it consists of 



1 proportional of peroxide of mercury = 216 80 



1 muriate of ammonia = 54 20 



270 Too 

 Having thus synthetically established the composition of 

 white precipitate, the following analytical experiment was made 

 upon it: 270 grains were dissolved in hydrocyanic acid, and 

 sulphuretted hydrogen was passed through the solution till it 

 occasioned no further change ; the precipitate was then col- 

 lected, washed, and dried : it weighed very nearly 232 grains, 

 being the equivalent of bisulphuret of mercury. The filtered 

 liquor, on evaporation to dryness, left 54 grains, or 1 propor- 

 tional of muriate of ammonia. — Journal of Science, Jan. 1825. 



ELECTRICAL CONDUCTING POWER OK MELTED RESINOUS 

 BODIES. 



It is commonly stated that melted resins become good con- 

 ductors of electricity, and freely allow of its transmission. The 

 following experiments were made with the view of determining 

 to what extent they possessed this property. 



Common resin, shell-lac, asphaltum, bees-wax, red and black 

 sealing-wax, were melted in separate glass tubes, fitted with 

 wires for taking the electric spark : they all slowly and with 

 difficulty diew off" the charge of a jar, and not with the facility 

 usually supposed. The melted contents of the same tubes 

 acted as non-condiictors when made part of the Voltaic circuit. 



Several 



