Miscellanies. 175 



and of facts, original and selected, well worthy of their serious 

 attention. 



Our space will enable us, at present, to take only a hasty view of 

 some of the most important of the original articles. 



. The first is a short paper "on the preparation of glauber and epsom 

 salt, and magnesia from sea water;" by Daniel B. Smith. After 

 stating the manipulations practiced in the large salt works of Massa- 

 chusetts, and giving the composition of sea water, as obtained by Dr. 

 Marcet, the author remarks that " The state in which these elements 

 exist in sea water, is involved in much obscurity. According to the 

 temperature employed in the evaporation, we procure from it either 

 sulphate of lime, sulphate of magnesia, or sulphate of soda. It is 

 therefore evident that a change of temperature is sufficient to disar- 

 range the combinations that usually obtain. 



" If we suppose the sulphuric acid to exist in combination with 

 soda, the following may be considered as the composition of one 

 thousand grains of sea water. 



Sulphate of soda, - - - 4.698 grains. 

 Hydrochlorate of magnesia, - - 6.4125 



lime, - - 1.625 



Chloride of sodium, - - - 26.27 

 " If it be combined with magnesia, the following arrangement may 

 be considered as obtaining : 



Sulphate of magnesia, - - 3.915 grains 

 Hydrochlorate of magnesia, - - 2.69325 



hme, - - 1.625 

 Chloride of sodium, - - 30.185 



" The latter formula agrees better than the former with the medi- 

 um, proportion of salt, (which is about 3 per cent.) in sea water." 



" The formation of Glauber's salt (it is added) cannot be advan- 

 tageous to the manufacturer. It lessens the production of common 

 salt about 13 per cent, and though the same quantity of magnesia can 

 be obtained from the bitterns, it will not yield Epsom salt." 



The next article is by the same author, and is entitled ^^ Remarks 

 on the common Hydrometer, with a description of a neiv method of 

 graduating that instrument." The author objects to the common in- 

 struments, that in all of them the scales are altogether arbitrary, and 

 will not compare with each other, and are not intelligible to the gen- 

 eral student ; and that the mode of graduation is very defective, as in 

 taking as starting points so small a part of the scale, the error of ob~ 



