1S15.] Royal Instilufe. 459 



tiling happens to the first class of bodies when tliey are sufficiently 

 heated to let go tlieir hydrogen. These experiments presented some 

 curious appearances. A mixture of starch and iodine, when tritu- 

 rated, assumes a red, blue, or black colour, according as the iodine 

 is more abundant, &c. 



But our associate Gay-Lussac is the person who has made the 

 most extensive and careful set of experiments on iodine. His paper 

 has been printed in tlie Annalos de Chimie. He examines iodine 

 itself, its combinations, and those of its two acids with ditiereut 

 bodies. These, according to tlie established rules of nomenclature, 

 are denominated iodurets, iodales, and hydriodales. He treats 

 likewise of chlorine, and makes some new remarks on its combina- 

 tions, all of which had not been correctly appreciated. Then con- 

 sidering prussic acid as essentially formed of azote, hydrogen, and 

 carbon, he concludes that azote ought likewise to be added to the 

 Hist of substances capable of producing acids without oxygen. This 

 Itads him to consider acidity and alkalinity as properties belonging 

 to certain bodies and certain combinations, without any necessary 

 relation to their composition, as far as can be discovered, and which 

 of consequence makes it approach to the ideas of Winter! and some 

 German (;hemists. This memoir is full of delicate investigations 

 and ingenious hints, of which it is not possible to give an accoimt, 

 but which will not fail to give a new spring to the most jjrofound and 

 most important department of cliemistry. 



Our re5pectai)Ie associate M. Sage, who, notwitfistanding his age 

 and infirmities, always takes a lively interest in new chemical facts, 

 has likewise made experiments on iodine, and on kelp, from which 

 it is obtained. He has oijserved the alteration produced by iodine in 

 the silver vessels in which it is heated. Kelp furnished him, by 

 naked distillation, products analogous to those of animals ; and by 

 macerating them in weak nitric acid, he obtained a cartilaginous 

 net, similar to that left by bones and by madrepores when deprived 

 of their earthy parts. M. Sage concludes, from these two facts, 

 that the fuci arc polypi. ' 



The same chemist has presented likewise a notice on the advan- 

 tages of reducing galena by the Hre. He affirms that by this method 

 much more lead is obtained than by tiic ordinary way. 



M. Theodore de Saussurc, correspondent, who in IHO7 had read 

 to the Class a memoir on the composition of alcohol and of sul- 

 phuric acid, of which we gave an account at the time, and from 

 which it resulted that ether contains more carbon and hydrogen than 

 alcohol, has last year lesnmed this important object of investigation, 

 and making use of methods at once more simple and more rigorous, 

 has obtained a moie craet result, liy passing these two liquids 

 through a red-hot porcelain tube, he convened them into water and 

 a gas, the analysis of which presented no «lilHculty. By this method 

 he ascertained that alcdhol and ether ennfain each an idcuiieal 

 proportion of carbon and liydrogen, and in the ^amc ratio that ihey 



