M. Uziglio's Analysis of the Waters of the Mediterranean. 81 



existence either in the ocean or the Mediterranean. It can- 

 not, however, be inferred that these beings have the power 

 of forming it ; it follows only that the absorbent organs of 

 vegetables and animals are more delicate and perfect than 

 our best methods of analysis. The quantity of bromine found 

 in sea-water prevents the detection of iodine ; the production 

 of the blue colour with starch may be effected or prevented, 

 at pleasure, by repeatedly adding to a liquid an iodide or 

 bromide ; iodine cannot therefore be detected in sea- water, 

 while it contains bromine. . 



In the second memoir, M. Uziglio has examined the 

 results of the evaporation of the water of the Mediterranean 

 at different degrees of the areometer, and those of its an- 

 alysis at different temperatures. He has given the result of 

 his experiments on the deposits of salts comparatively with 

 the thermometer and areometer ; those tabulated results, 

 however useful to the manufacturer, are not susceptible of 

 analysis. 



M. Uziglio has given a table (which is capable of being 

 advantageously extended for the use of the manufacturer) of 

 the different saline deposits obtained at different densities. 

 The tables which precede it shew that the progress of the 

 continual evaporation of the water, in salt-works, is identical 

 till the density reaches 25°, and is pretty well maintained up 

 to 30°; but beyond this, and when approaching 35°, the 

 difference between day and night complicates the phenomena, 

 so that very variable mixtures of common salt, sulphate of 

 magnesia, and chloride of magnesium are obtained. 



The results of evaporation are still more variable above 

 35°. The mixtures of the salts deposited undergo numerous 

 differences in their composition, without the possibility of 

 foretelling the result of the precipitations ; some contain 

 from 0*5 to 0-17 of their weight of potash ; it sometimes 

 happens that this substance is found in deposits formed in. 

 solutions, the density of which is only from 34° to 35° ; these 

 deposits are derived from variations in the composition of the 

 waters. — V Institute Fevrier 27, 1850, and Phil. Mag., vol. 

 xxxvi. p. 440. 



'vol. L. no. XCIX. — .TANUAllY 1851. P 



