CHEMISTRY. 449 



Putrescin. — This coiiipouiul, analogous to cadaverin, has been identi- 

 fietl withtetraiiieth3ieiiediainineby Udraiizky and Bawniaun. (Berichte, 

 XXI, 2938.) 



Identihj of the naphtenes icifh the aromatic he.rhi/drides. — In 1883 Mar- 

 kownikoff and Ogloblin obtained from Caucasian petroleum a series of 

 hydrocarbons isomeric with the aromatic hexhydrides, to which they 

 gave the name of naphtenes. Kouovaloff, studying the hexhydro- 

 pseudocumene, which he prepared synthetically from pseudocumene, 

 finds it to be in all respects identical withnononaphtene, and concludes 

 that the supposed naphtenes, as an independent series of hydrocar- 

 bons, do not exist. (Berichte, xx, ref. 570.) 



Action of pyridine on metallic salts. — The observations of Jorgeu sen 

 upon metallic pyridine compounds have been extended to a number of 

 new cases by Lang. When pyridine in excess is added to a solution of 

 zinc chloride, a voluminous white- precipitate is formed. This dissolves 

 in boiling water with which pyridine has been mixed and crystallizes 

 out in long silky needles having the composition ZUCI3 . 2C5H5X. It is 

 recrystallable from boiling alcohol, but water decomposes it into free 

 pyridine and a basic chloride. 



From an alcoholic solution of copper chloride pyridine precipitates 

 magnificent bluish-green needles of CUCI2.2C5H5K With copper sul- 

 phate dissolved in water, pyridine produces a heavy, light green pre- 

 cipitate, which dissolves iu excess of the reagent. From the latter so- 

 lution alcohol throws down the compound CulS()4.C5El5N.3H20, which 

 is essentially the normal sulphate with two of its water molecules 

 replaced by one of the organic base. Cuprous chloride treated with 

 j)yridiue in absence of air reacts so strongly that the mixture becomes 

 boiling hot. Upon cooling the solution, crystals of CU2CI2.4C5H5X are 

 deposited. With great excess of pyridine, six molecules are taken up, 

 forming the salt Cu2Cl2.GC5Hr,X in long, greenish-yellow needles: 



With an alcoholic solution of cadmium chloride, i)yridiiie precipi- 

 tates the salt CdCl2.2C5n5"N'. A similar salt, highly crystallized, is 

 also formed by cadmium iodide. With mercuric chloride a compound 

 HgCl2.C5lJ5N is produced. Anhydrous cadmium chloride absorbs three 

 molecules of pyridine with evolution of heat. Other salts of colnilt 

 chloride, ferrous suli)hate, and nickel sulphate with i)yridine were also 

 prepared. 



(Berichte, XXI, 1G78.) 



Pijridin and piper id in. — In a paper of nearly a hundred pages, Lad- 

 cnburg presents the collected results of recent investigations made 

 partly by himself and partly by students under his direction, concern- 

 ing the prei)aration and properties of the pyridiu, and pipeiidin bases. 

 The compounds were partly synthetic, and in j)art derived from tar 

 oil, and embrace pyridin, three methylpyridins, two ethylpyridins, 

 isopropylpyridin, two dimethylpyridins, three methylethylpyridins, di- 

 ethylpyridin, and the corresponding members of the piperidiu series. 

 H. Mis. 142 20 



