I'h diol M<>i' — Ih t> rut noit ton of Chlorine, 293 



P. S. — Since writing the above I have come across fche fol- 

 lowing titles, but have soon only one of the papers : 



Pernter, Die allgemeine Circulation der Atmosphare. Wien. 1889, 

 Kftppen, Oeber die allgemeine Circulation dor Atmosphare. 



Humboldt, Dee., 1888. 

 Marchi, Saggio d'Applioazione dei Principii dell 1 Idrauiica alia 



Teoria delle Correnti dell' Aria. Rome, 1889. 

 Roth, Der Einfluss der Reibung auf die Ablenkung dor Bewe- 



gungen kings dor Erdoberflache, Woohens. f. Astron., 



1886 (modified by communication written in 1888). 



The recent treatises of Bianford and Abercromby should 

 perhaps also be mentioned in this list. 



Art. XXXVII. — Two Methods for the Direct Determination 

 of Chlorine in Mixtwn 8 of All- aline Chlorides and Iodides • 

 by F. A. Gooch and F. W. Mar 



[Contributions from the Kent Chemical Laboratory of Yale College — II.] 



The determination of chlorine associated with iodine in 

 haloid salts is usually accomplished by differential or indirect 

 means : either the two halogens are determined together in a 

 portion of the assay while the iodine alone is estimated in a 

 second portion by one or other of well known methods, the 

 difference between the sum of the halogens and the iodine 

 being the chlorine sought ; or, the silver salts of the halogens 

 are weighed together and then converted into a single salt, or 

 the metal, the ratio of chloride to iodide in the original salt 

 being found by simple algebraic processes. If the amounts of 

 iodine involved are minute, it is possible to separate that ele- 

 ment by Fresenius's method of treatment with nitrous acid 

 and a solvent like carbon disulphide, and then to determine 

 chlorine directly in the residue ; but the manipulation of the 

 process is difficult, and the results inaccurate, when much 

 iodine must be removed. The only method which has been 

 deemed generally applicable to the direct estimation of 

 chlorine associated with iodine in haloid salts is based upon 

 Lassaigne's reaction, by which the iodine is precipitated as 

 palladious iodide: but, the necessity of removing the excess 

 of palladium by hydrogen sulphide before proceeding to pre- 

 cipitate the chlorine is so irksome that, even in this process, it 

 is found to be more convenient to fall back upon the estima- 

 tion of chlorine as the difference between the iodine found 

 by the palladium process and the sum of the iodine and chlo- 

 rine obtained by another test in another portion of the material. 



