404 Intelligence and Miscellaneous Articles, 



decomposition, small quantities of a very dilute solution of muriate of 

 barytes, or of sulphate of silver, are to be added, as either salt may be 

 in excess. In this, as in the preceding case, the liquor ought to be 

 again passed through linen, to separate the precipitated matters. It 

 is certainly possible to obtain the liquor perfectly neutral, but it is 

 better that the sulphuric acid should be slightly in excess ; a little 

 barytes water will afterwards precipitate it, and all chance of decom- 

 posing the peroxide of hydrogen will be avoided. 



Lastly, having filtered the liquor through paper, it is to be con- 

 centrated as usual under the receiver of the air-pump. There is no 

 difficulty in charging it very quickly with 60 to 80 times its volume of 

 oxygen by the processes which have been described, before any con- 

 centration ; only instead of dissolving the peroxide in a glass vessel, 

 it is much more convenient to do it in a platina or silver vessel sur- 

 rounded with ice, and to rub continually with a pestle the hydrated 

 and divided peroxide. — Ann. de Chim. et de Phys. t torn. 1. p. 80. 



COMPOSITION OF CAFFEIN. 



MM. Pfaff and Liebig have analysed caffein, and find it to be com- 

 posed of, taking the mean of two experiments, 

 Carbon 49 86 

 Hydrogen 5*32 

 Azote 29*03 

 Oxygen 1580 



100-01 

 which they consider as equivalent to 



Four atoms carbon 3-05750 or 49*79 

 Five atoms hydrogen 031 199 5-08 



Two atoms azote 1*77036 28*83 



One atom oxygen 100000 16-30 



6-13985 100*00 

 At the request of MM. PfafF and Liebig, M. Wohler also analysed 

 caffein, and with results almost precisely similar to those above stated. 

 — Ann.de Chim.et de Phys., tom.xlix. p. 303. 



To the analysis, the authors have appended the following observa- 

 tions, which constitute a fine example of the confusion which chemistry 

 is doomed to suffer from the wild theories and speculations which are 

 now so rapidly rising into fashion : — 



"According to its theoretic composition, caffein may be regarded 

 as a combination of a cyanic acid, which contains one half less oxygen 

 than the common acid, with aether analogous to cyanic aether. An 

 aether formed of a problematical cyanous acid would be composed of, 

 Ci/40 + (C 2 HH|0 H2)=:OHs N*Oj this formula is the 

 same as that of caffein." R. P. 



ANALYSIS OF THE SULPHO-PLUMBIFEROUS TELLURIUM. 



M. Berthier remarks that the onlv ore of Tellurium which can be 



* 



ffldlU ana: 



