484 Miscellaneous Intelligence. 



nibbed over them by means of a brush, until they have acquired 

 the deep red colour of copper ; they are then to be left for an hour 

 to dry, after which they are to be polished with "a very soft brush 

 and rouge, or the red oxide of iron in fine powder, the breath 

 being" passed over them from time to time to cause the adhesion of 

 the rouge. The polish is to be completed by the brush alone, the 

 medals being passed now and then over the palm of the hand. If 

 the bronze is to resist humidity, it should be covered with a thin 

 film of gold lacquer. 



The pieces of metal formed from Darcet's alloy are bronzed by 

 the use of the second solution only, and do not require lacquering 

 for the purpose of protecting them from the action of water. — Bull. 

 Univ. F. vii. 88. 



21. Chromate of Silver crystallized. — Mr. Teschemacher obtained 

 crystals of this salt from the solution left after separating the preci- 

 pitate occasioned by adding nitrate of silver to chromate of potash. 

 The solution being allowed to evaporate spontaneously, produced 

 the crystals at the end of ten days. The crystals had a strong 

 metallic lustre, and were of a deep red colour by transmitted light, 

 much resembling native fed silver. They were insoluble in cold or 

 hot water, and were reduced by heat to metallic silver and chromic 

 oxide.— P/«7. Mag. N. S. i. 345. 



On a former occasion, the formation of artificial crystals of chro- 

 mate of lead was noticed*; and it is much to be desired that 

 chemists would attend, as Mr. Teschemacher has done, to the 

 production of the crystals of substances usually considered as inso- 

 luble, many of which can no doubt be formed by the use of alkaline, 

 acid, or saline solutions. 



22. Sulphate of Quinia. — According to the account of MM. 

 Pelletier and Caventou, the large quantity of 90,000 ounces of sul- 

 phate of quinia was manufactured in 1826 in France; a quantity 

 which could not have been administered to less than 1,444,000 

 persons. 



23. Adulteration of Sulphate of Quinia with Sugar. — M. Winkler 

 has met with sulphate of quinia, in commerce, adulterated with 

 sugar. The quantity of adulteration was ascertained by dissolving 

 the salt in water, precipitating the quinia by carbonate of potash, 

 filtering the liquid, evapornting to dryness, and digesting the 

 residue in alcohol. This fluid left the sulphate and carbonate of 

 potash, but dissolved the sugar, and, by evaporation, yielded the 

 latter in its separate state. ; 



M. Winkler has also met with benzoic acid adulterated with 

 sulphate of lime, in crystals. — Bull. Univ. C. x. 178. 



♦ Quarterly Journal of Science, xix, 155. 



