530 MISCELLANEOUS, 
the base of the Lower Silurian series by Mr. Billings, and an analysis by Prof." 
Sterry Hunt of Barrande’s recent Review of the Primordial Zone of North : 
America. Dr. Dawson contributes some Additional Notes on Aboriginal Anti- 
quities found at Montreal. 
On the Dimorphism of Arsenic, Antimony, and Zine. By Josiah P. Cooke, Jr. 
(From the Amer. Journ. March, 1861.) Both Arsenic and Antimony as occurring 
in nature, and as commonly obtained in the reguline state, are well known to 
erystallize in rhombohedral or hemi-hexagonal forms. Zinc, as artificially pro- 
duced, has been generally referred to the Hexagonal, or to the Trimetric system. 
The experiments of Professor Cooke as detailed in this memoir, seem to prove 
conclusively, however, that these metals may be also made to assume a mono- 
metric crystallization. Arsenic and Antimony were crystallized by sublimation 
in a current of hydrogen gas. They gave minute octahedrons, combined at 
times, in the case of the antimony crystals, with the faces of the cube, and in 
one instance, with those of the rhombic dodecahedron. These modifications do 
away with all suspicion that the minute crystals may have consisted of rhombo- 
hedrons with truncated polar angles. The crystals were moreover carefully 
examined in order to prove that they did not consist of partially-reduced 
arsenious acid on the one hand, and of oxide of antimony on the other. The 
oxidation of the metals would scarcely have taken place however, as these 
experiments were conducted. Zinc in combination with variable amounts of 
copper has been shewn by Storer to crystallize in regular octahedrons, and 
Professor Cooke describes some octahedral crystals of zinc and arsenic, in which 
the latter metal was in too smail a proportion to form a definite chemical com- 
pound. The heteromorphous character of these metals appears therefore to be 
fairly established. E. J.C. 
MISCELLANEOUS. 
ON CLEANING AND° PREPARING DIATOMS, ETC., OBTAINED FROM SOUNDINGS. 
: BY J. B. DANOER. 
The first operation generally required is to separate the soundings from the 
tallow or fatty matter which has been employed to bring them up from the bot- 
tom. I may here mention that Lieutenant Stellwagen, an American officer, has 
invented a sounding-lead which does not require grease. It has a trap at the 
bottom for collecting the soundings. J am sure our section will join with me in 
the wish that the soundings which our worthy Secretary hopes to receive from 
various parts of the world may be collected with an apparatus of this kind. 
The grease involves a considerable amount of trouble, and some loss. The mass 
of soundings and grease is to be placed in a basin or an evaporating-dish, and 
boiling water poured on it; the melted fat rises to the surface, and when cold can 
be easily skimmed off. This operation may be repeated until the sediment 
appears free from grease; to insure this, draw the water carefully from the 
sediment, and pour liquor ammonia on it; I prefer it to potass or soda; this will 
combine with the grease, if any remain, and form a soapy solution. This may 
now be treated with hot water for the final washing. This sediment must be 
allowed to settle quietly for an hour or two each time before the water is carefully 
