Chemical Science. 165 



over pure water. From this it results, that the air will not 

 carry off water from the Dead Sea, except when below 82° of 

 humidity, and that it will give water to it, when it is above that 

 point. The borders of the Dead Sea should, therefore, constantly 

 enjoy a dry atmosphere. It is very probable that that sea has 

 arrived at a fixed degree of saltness, relative to the humidity 

 of the air and its temperature ; a conjecture which could 

 be verified if the mean hygrometrical degree at its surface 

 were known. 



100 parts of the water gave, by evaporation, a saline resi- 

 duum, which, when dried perfectly, account being taken of the 

 muriatic acid which the heat disengaged, weighed 26.24. This 

 residuum was composed of 



Chloride of sodium, (common salt). 6.95 



Chloride of calcium (muriate of lime) .... 3.98 

 Chloride of magnesium(muriate of magnesia)15.31 



26.24 

 It contained also, a small quantity of chloride of potassium, 

 (muriate of potash) and traces of a sulphate, probably with a 

 base of lime. 



From an examination of the water of the River Jordan, it was 

 found to contain principally common salt, with some muriate of 

 magnesia, a very slight quantity of sulphate of lime, and, pro- 

 bably, also muriate of lime, but in very minute quantity. This 

 salt did not appear to be in the same proportion as in the 

 water of the Dead Sea. The sulphate of lime, for instance, is 

 relatively in more abundance in the first ; but it is probable that 

 the large (juantity of muriate contained in the latter, prevents 

 the sulphate of lime from remaining in solution. 



Annales de Chimie. xi. p. 195. 



8. Chcsnut Wood substituted for Oak-bark. — There is an ac- 

 count given l)y Mr. W. Sheldon, in Professor Silliman's Journal, 

 of tlic chcsniit-trce, and llic application of its wood to the pur- 

 poses of tanning and dyeing. By analysis it has been found 

 lliut chcsnut ivood contains twice as much tanning as cleaned 



