234 Scientific Intelligence. [March, 



to conclude, that much less than a millionth part of potassium, 

 or a 100,000th of zinc, is sufficient to impart this singular 

 property to mercury. Lead and tin act with much less energy. 

 Bismuth, copper, silver, and gold, not at all. A number of 

 singular phenomena in the electrization of mercury and other 

 metals are described ; and some calculations added respecting 

 the intensity of the forces acting on the molecules of the 

 electrified body, which Mr. H. concludes, in his experiments, 

 to have been not less than 50,000 times their gravity. 



In the sequel, Mr. Herschel notices the curious gyratory 

 motions, observed by M. Serrulas, in fragments of alloy of 

 potassium and bismuth, when floated on mercury under water; 

 the cause of which he shows to have been misunderstood by 

 Mr. S. and which admit of easy explanation on the principles 

 of this Lecture. 



For the sake of such of our readers as may wish to repeat 

 these experiments, we may mention, that it is absolutely neces- 

 sary to use mercury recently distilled and purified, by washing 

 with dilute nitric acid, and that all the vessels employed must 

 be scrupulously clean, and the surface of the metal free from 

 any adhering film. A small battery of eight or ten pairs of 

 single plates is sufficient to exhibit all the phenomena. 



Article XVI. 



SCIENTIFIC INTELLIGENCE, AND NOTICES OF SUBJECTS 

 CONNECTED WITH SCIENCE. 



I. Primary Forms of Sulphur. 



Our readers may have remarked in the present volume of the Annals, 

 a description by Mr. Brooke, of two primary forms of sulphate of 

 nickel. A paper appears in the Annales de Chimie, for Nov. 1823, by 

 Mr. Mitscherlich, announcing the discovery of two primary forms 

 of sulphur. The one, that which occurs in nature, an octahedron 

 tvith a rhombic base ; the other, an oblique rhombic prison, P. on M. 

 measuring 9*° 5' and M. on M. 90° 32', produced by fusing sulphur 

 in a vessel, in which it may very gradually cool ; when a crust is 

 formed round the mass, it is to be broken, and the sulphur which 

 remains fluid to be poured out ; the crystals will appear lining the 

 cavity. 



Mr. M. appears to consider that all substances which produce 

 crystals, may likewise assume two primary forms. 



This gentleman has crystallized phosphorus from a solution of 

 phosphuret of sulphur, the form of which is the rhombic dodecahe- 

 dron. 



