374 Miscellanies. 



Take one part of kaolin, one and a half of sulphur, and one and a 

 half of pure and dry sub-carbonate of soda ; mix them carefully and 

 introduce the whole into a coated earthen ware retort, and heat the 

 mixture gradually until the vapor has entirely ceased. On cooling, 

 it forms a spongy mass, which reflects, at first, a green tint, but on 

 exposure to the air, it becomes more and more blue. Leach this 

 mass : the excess of sulphur is dissolved, and there remains a pow- 

 der of a good blue. It is to be washed by decantation, dried, and 

 calcined to a cherry red, to drive off the excess of. sulphur. 



The greatest defect of the color thus obtained is want of intensity. 

 The purple shade, which the natural ultramarine does not possess, 

 at least in so marked a degree, may well owe its distinctness to sub- 

 stances employed in refining it. It is certain that when the Guimet 

 blue is heated, it loses in a great degree its azure tint, and if the ex- 

 periment is made in a tube, oily streaks issue from it, which must ne- 

 cessarily proceed from organic substances. — Rev. Encyc. Dec. 1832. 





11. Opium. — M. Pelletier has just discovered (announced to the 

 Academy on the 24th of December,) in this very complex material, 

 a new crystalline substance, analogous (isomere) to morphine, (para- 

 morphine,) which had escaped his first researches. It differs, essen- 

 tially, from morphine in its chemical properties, although its element- 

 ary composition appears the same. It cannot be confounded, either 

 with the Codeine of Robiquet, or with other substances found in opi- 

 um. Its savor is like that of pyretre; its solubility in alcohol and ether 

 is infinitely greater than that of narcotine, from which it differs also in 

 crystalline form and fusibility. From an experiment made by Ma- 

 gendie, it has a powerful action on the animal economy — a very fee- 

 ble dose killed a dog in a few minutes ; it acts on the brain and pro- 

 duces convulsions. — Idem. 



12. Combinations of azote. — M. Despretz announced to the 

 Academy, at its session on the 5th of November, that he has ascer- 

 tained that azote combines directly with iron and copper. The pro- 

 ducts are analogous to those on which he read a memoir two years 

 ago. The azote which he employed, came either from the decom- 

 position of ammonia by chlorine, or from that of the deutoxide of 

 azote by iron or copper. In both cases, the gas, in reaching the 

 metal, was dry and deprived of foreign matters which might have 

 influenced it. It is, as he thinks, the first example of azotic combi- 



