Foreign Literature and Science. 393 



"S 



These figures embrace all the modifications possessed by 

 the collection sent hither by Dr. P. with the exception of a 

 crystal, in which, one of the solid angles formed by the meet- 

 ing of the prism with the pyramid, was replaced by a single 

 plane, whose inclination to the adjacent planes, it was impos- 

 sible to ascertain, owing to its smallness and want of lustre. 

 The beautiful form, fig. 1, appears to be the most abundant 

 modification of this locality. In some cases, the prism inter- 

 vening between the two pyramids is not so long as is repre- 

 sented in the annexed diagrams, and rarely, it is so short, as 

 to bring the bases of the pyramids nearly into contact. 



II. Foreign Literature and Science, extracted and translated 

 by Prof. J. Griscom. 



1 . Remedy against the dangers of the inspiration of Chlo- 

 rine. — M. Kastner has advised liquid ammonia on sugar. 

 The following method is of certain efficacy ; it consists in 

 breathing the vapor of spirits of wine, or in swallowing lumps 

 of sugar, steeped in alcohol. — -Annales des Mines, prem. Liv. 

 1827. 



2. Chemical researches on Starch, by J. B. Cavebtton. — » 

 Starch is insoluble in cold water ; it forms with boiling water 

 what is called, (in French,) empois. I distinguish two kinds 

 of empois : 1, that which contains the least starch, (minimum 

 d'amidon,) and which is entirely transparent, and soluble in 

 cold water ; 2, that which contains the most starch, (maxi- 

 mum d'amidon,) which is almost entirely opaque, because it 

 contains starch in suspension. Starch, rendered soluble in 

 cold water, is modified in its properties ; it is the amidine of 

 M. de Saussure ; its characters are solubility in cold water, 

 and the property of acquiring a blue color by Iodine. 



If a solution of starch is boiled for a long time, it assumes 

 with Iodine, a purplish color. Starch may be brought imme- 

 diately to the same condition, either by a strong torrefaction, 

 or by heating it with sulphuric acid, diluted with twelve times 

 its weight of water. 



If a hot solution of starch be left to itself, during some 

 weeks in the heat of summer, it becomes sour ; and if it be then 

 diluted with water, and filtered, the liquor becomes colored 



Vol. XIII.— No. 2, 25 



