Scientific Intelligence. — Chemistry. 189 



riie conjunctiva. 4. That the oxide of osmium occasions more 

 speedy vomiting than any other metal. 3. That sulphate of man- 

 ganese injected into the vascular system, occasions a powerful ac- 

 tion of the liver, causes inflammation of that organ, and increases 

 very much the secretion of the gall, so that the larger vessels 

 become of a yellow colour. 



12. Salts assume different primitive forms, according to the 

 menstruum in which they crystallise. — We are informed, that a 

 German chemist, Dr Wollner, has found that one and the same 

 salt assumes different fundamental or primitive forms, accord- 

 ing to the nature of the liquor in which the crystals are formed. 

 In illustration of this statement, he says, that, when a small 

 portion of solution of sulphate of iron is poured into a solution 

 of alum, and the whole allowed to crystallise, the sulphate 

 of iron assumes the octahedral form of the alum, although these 

 octahedral crystals contain scarcely a trace of alum. 



V6. Compound for preserving Substances from Humidity. — 

 When a mixture of one part of oil and two parts of resin is 

 forced, by the application of a high temperature, to penetrate 

 porous substances, as building-stones, plaster, &c., it renders 

 them perfectly impermeable to moisture. 



14. Inconveniences of the pressure apparatus Jor Coohing.—- 

 In the miUtary establishment of Carlsruhe, the alimentary sub- 

 stances are cooked in vessels composed of tinned iron, in which 

 the temperature can be augmented by pressure. M. Geiger has 

 detected in all the substances so prepared a small quantity of tin 

 and lead, which varies according to the nature of the substance 

 cooked, and the time it has remained in the apparatus. He 

 thinks that the continual presence of these metals in the food ta- 

 ken by the same persons, although they may exist in but very 

 small proportions, must prove hurtful to their health. 



15. Carbonate of Magnesia. — According to Bischof 1363 

 parts of water dissolve 1 part of carbonate of magnesia, which 

 is a larger portion than stated by Dr Fyfe, who found that it re- 

 quired 2632 parts of water to dissolve 1 part of carbonate of 

 magnesia. 



16. Changes that take place in the teocture of different solid 

 substances in the course of time. — Common barley-sugar when 



