25S 
MISCELLANY. 
Mercaptan.— M. Zeise states, that when the sulphovinate of potassa, 
baryta or lime, is heated in a distilling apparatus, with a concentrated solu- 
tion of protosulphuret, deutosulphuret or hydrosulphuret of barium, the 
sulphovinate is change it^o a sulphate, and there is formed an etherial 
liquid, which is condensed with a little water in the recipient, without 
the disengagement of sulphuretted hydrogen. This liquid, purified and 
deprived of its water by means of chloride of calcium, is lighter than 
water, colourless, of an odour excessively penetrating, somewhat resem- 
bling assafcetida or garlic, and has an extremely strong taste. It takes fire 
readily, and gives off when burning the odour of sulphurous acid. Dis- 
tilled with care there are obtained two substances, the least volatile of 
which is Thial/'c ether, and the other Mercaptan. This last is a limpid 
fluid even at 10°; it is destitute of colour. Its odour is peculiar, and ap- 
proaches that of garlic or assafcetida ; its taste is sweetish and etherial; 
density 0.842, boiling point 3°. It is slightly soluble in water, but 
largely so in alcohol or ether. It combines with potassium, giving up 
its hydrogen, and producing a saline mass, colourless and very soluble, 
which gives a yellow precipitate with the salts of lead, and a white with 
the deutochlorides of mercury, gold and copper. When placed in contact 
with the deutoxyde of mercury, the mercaptan attacks it with violence, 
and produces a colourless crystalline body, together with some water. 
The mercaptide of mercury melts at 187°; commences to change its ap- 
pearance at 257°; and is decomposed at 347° with a disengagement of 
thialic oil. It is insoluble in water and alcohol, and is not acted upon by 
a concentrated solution of potash, and probably not by any of the acids 
except the nitric. The mercaptide of platinum changes into a sulphuret 
by calcination ; the mercaptide of gold is colourless and destitute of lustre; 
the mercaptides of potassium, &c. have an alkaline reaction. In a dry 
state, no change is caused by a heat of 212°. In solution, the effect of 
heat is soon apparent. The composition of mercaptan corresponds exactly 
to that of alcohol. Jim. Journ. Sci. and Jinn, de Chim. 
Tincture of Copaiba — This is said to be the best form for administering 
the copaiba. It is made by rubbing together twelve ounces of copaiba 
and six of calcined magnesia, and digesting in a pint of alcohol, filtering 
and adding half an ounce of sweet spirits of nitre. The dose is a 
drachm two or three times a day, gradually increased to half an ounce. 
Am. Journ. Med. Sci. and London Med. Gaz. 
Quassin. — This bitter principle has been obtained in a crystalline state, 
by Winckler, by digesting three ounces of pulverized quassia in two 
pounds of alcohol of 80° ; evaporating the tincture in a water bath, dis- 
solving the remainder in water, filtering the solution, and again evapo- 
rating in a water bath to the consistence of a thick extract ; treating this 
