200 On the Sea Water on the Coasts of France. [Sept. 



Article VI. 



Memoir on the Sea Water on the Coasts of France, considered in a 

 chemical and medical point of view. By MM. Bouillon La- 

 grange, and Vogel.* 



We shall not attempt here to notice the phenomena which the 

 sea presents. The most astonishing is, no doubt, the ebbing and 

 flowing of the tide. This is a daily, periodical, and regular mo- 

 tion, observed in the water, to which the name of tide has been 

 given. On this subject interesting details may be seen in the 

 researches of Euler, Daniel Bernoulli, and Maclaurin. 



The luminous appearance of the surface of the sea has likewise 

 excited the attention of navigators and philosophers. Some have 

 ascribed it to a phosphorescent matter, while others have considered 

 it as an electrical phenomenon. 



As to the saltness of the sea in general, it is very difficult to 

 account for it. Some philosophers have supposed that the sea is 

 perpetually dissolving the salt which is accumulated at its bottom ; 

 and that its saltness has existed from the first, because it contains 

 animals which cannot live in fresh water. Be that as it may, the 

 sea is more salt in hot regions than in the temperate parts of the 

 earth; perhaps on account of the greater evaporation which takes 

 place in these parts. Sea water has likewise a bituminous taste, 

 often injurious to weak stomachs. 



Among the attempts made for many years to deprive sea water of 

 its salt, those of Mr. Appleby have had a kind of celebrity. They 

 were the consequence of the ideas of Hales, who gave on this sub- 

 ject very interesting details. His method consisted in putting four 

 ounces of solid caustic potash, and as much calcined bones, into 

 about 80 pints of sea water. The water distilled from this mixture 

 becomes sweet ; but still retains a disagreeable taste. Rouelle 

 repeated these experiments with success. M. Poissonier, sen. a 

 Member of the Faculty pf Medicine of Paris, likewise made expe- 

 riments on this subject. His method was distillation in an appa- 

 ratus consisting of tin tubes placed at the orifice of the alembic. 

 He added some alkali to sea water before distilling it. 



Another method was proposed, in 1/72, by Dr. Irving. It con- 

 sisted in a single large tube in place of the worm of the still, 

 without capital, and without mixing any ingredient whatever with 

 the sea water. This tube, which has the form of a funnel, is 

 capable by its shape of being applied to the mouth of all the vessels 

 used on ship-board for boiling. 



MM. Macquer and Monnet likewise proved that sea water might 

 be distilled without any mixture, and a potable liquid obtained. 



* Translated from the Ann. dc Chira. toI. Ixxxyii. p. 190. 



