Til E 
VETERINARIAN. 
VOL. XXXIV. 
No. 406. 
OCTOBER, 1861 . 
Fourth Series. 
No. 82. 
Communications and Cases, 
SCIENTIFIC AND ANALYTICAL CHEMISTRY. 
ON A NEW FORM OF CHLORIDE OF SODIUM. 
By Richard V. Tuson, 
Professor of Chemistry to the Royal Veterinary College, 
and Lecturer on Chemistry at Charing Cross Hospital. 
That chloride of potassium, which ordinarily crystallizes 
in cubes, is nevertheless often found as an efflorescence on 
various vegetable extracts assuming the acicular form, is well 
known. 
Hitherto, I believe, the corresponding compound, chloride 
of sodium, has never been observed in needle-shaped crystals, 
but nearly always in cubes. 
Occasionally, however, it deposits from urine in octahedra, 
and when a solution of the salt in water is evaporated at a tem¬ 
perature not exceeding 14° Fahr. it crystallizes in hexagonal 
tables (Ehrenberg), which contain, according to Fuchs, six 
equivalents, but, according to Mitscherlich, four equivalents 
of water of crystallization. At temperatures above 14° Fahr. 
these hexagonal crystals lose their water of crystallization, 
and are resolved into a congeries of minute cubes. Chloride 
of sodium, it is also stated, may be obtained in large, oblique 
rhombic prisms, having the formula NaCl + 4Aq. They efflo¬ 
resce in air below 32° Fahr. (Mitscherlich), deliquesce (? efflo¬ 
resce) in air above 32° Fahr. (Fuchs), and leave a powder of 
small cubes. 
Lately, on opening a tightly fitted tin box, in which a 
quantity of salmon-roe paste had been allowed to remain for 
nearly three years, it was found that the organic matter was 
covered by an efflorescence of acicular crystals. One of my 
xxxiv. 43 
