1835.] 



Scientific Intelligence. 



395 



Distilled water ut 38- J F. 2 ' 

 Potash sulphate of alumina 4°30 

 Chloride of lime . 

 Chloride of potassium 

 Sulphate of magnesia 

 Sulphate of iron . . 

 Chloride of sodium . 

 Nitrate of potash . . 

 Muriate of ammonia 

 Chloride of barium . 

 Acetate of lead . . 



Binoxalate of potash . .14 

 Sulphate of copper . . 20 

 Nitrate of mercury . . 35 

 Nitrate of silver ... 45 



Oxalic acid 14 



Tartaric acid ..... 10 

 Muriatic acid . , . .10 

 Sulphuric acid ... 8 

 Nitric acid ..... 8 



Potash 15 



Ammonia 8 



He found the opinion of Faraday correct, that the conductibility 

 which non-conducting solids acquire by fusion, proceeds from the 

 same source as the conductibility which these bodies communicate to 

 water by their solution in the latter. This is strikingly exemplified 

 in the cases of sugar and iodide of sulphur. 



He found the conductibility of phosphate and pyro-phosphate the 

 same ; which proves that heat does not alter the conductibility of 

 this substance, although it produces a powerful alteration in its che- 

 mical properties. 



II. With regard to the effect of quantity of dissolved matter upon 

 the effect, he found that, with chloride of potassium, there was the 

 same deviation with 40 grs. to the thousand of water as with 100, — 

 the deviation being 40° ; and when a great quantity of salt was added 

 the effect was not increased. 



With 10, 20, and 40 grs. of chloride of sodium the deviation was 

 ^^. With 80 grs. 4°, and at the point of saturation it was also 4^. 



When acetate of lead was employed the deviation with 10 grs. was 

 8''-30 , 20 grs. 9«, 40 grs. 9'"30, 80 grs. 9°. At the point of satura- 

 tion 6<^ to 7^". With nitrate of silver, when \ gr. was dissolved the 

 deviation was 3^ 1 gr. 10% 5 grs. 14«, 10 grs. 18°, 20 grs. 22^, 25 grs. 

 22°, 30 grs. 22°, 40 grs. 21°. Hence, the supposition is confirmed 

 that the increase of conductibility, which results from a greater pro- 

 portion of salt dissolved, remains longer when the solution, though 

 very feeble, possesses great conductibility. 



The author ascertained a remarkable fact, which may be compared 

 to the known property which liquids possess, of evaporating in a 

 vacuum already saturated with vapour proceeding from another 

 liquid. We know that, in this case, while the second liquid cannot 

 form any more vapour, the first can evaporate in the same space, as 

 if this space had not been saturated with any other vapour. When 

 a solution has acquired the highest degree of conductibility, in such 

 a manner that the addition of a new dose of the salt only diminishes 

 it, if we dissolve in the liquid another salt, without decomposition, 

 the conductibility increases, as if the substance already dissolved did 

 not exist. The phenomenon disappears if in the mixture a decom- 

 position takes place, giving rise to the precipitation of an insoluble 

 salt. The conductibility, on the contrary, is diminished The chlo- 

 ride of iodine, proto-iodide of tin, chloride of copper, when added in 

 convenient quantities, to a solution of chloride of sodiup exhibit a 

 conductibility almost metallic. 



