Intelligence and Miscellaneous Articles. 325 



Oxygen 21-476 



Tin 78-524 



100-000 



These results give 731-23 as the atomic weight of tin. M. Ber- 

 zelius gave in 1835 the number 735-296, which has been generally 

 adopted. 



It is, however, admitted that the analyses cited were not of a nature 

 to supply the exact value of the atomic weight of tin, although they 

 show with certainty that it requires some alteration. 



To decide this question several experiments were made with all 

 the precautions required by operations of this nature. One hundred 

 parts of perfectly pure tin, reduced in various ways from its oxide, 

 gave 127-56, 127-56 and 127-43 parts of peroxide of tin. The 

 atomic weight calculated from the first two experiments, which gave 

 the same numbers, is 725-7. These analyses were performed by 

 M. Vlaanderen. 



This result places tin in the series of metals, the atomic weight of 

 which is expressed by a multiple of that of hydrogen ; the number 

 725, which is 58X12-5, may be hereafter adopted for the equivalent 

 of tin, seeing that the difference of 0'7 in 725 cannot be detected 

 by chemical analysis. The composition of peroxide of tin inferred 

 is therefore — 



Oxygen 21-62 



Tin 78-38 



100-00 

 Journ. de Pharm. et de CMm., Janvier 1850. 



ANALYSIS OF THE MUD OF THE NILE. 



The first analysis was made by M. Lajonchere in the laboratory 

 of M. Payen; it was supplied by M. D'Arcet, Jun. The specimen 

 was in irregular masses, which were readily reduced to a fine powder ; 

 it was soft to the touch, and contained brilliant grains. It adhered 

 slightly to the tongue, and had a sensibly saline and acrid taste. Its 

 density was 2-5, nearly equal to that of various fertile soils. When 

 calcined in the air it assumes a reddish-brown colour, loses weight 

 by the evaporation of water and the combustion of organic matter ; 

 when calcined in close vessels, it yields alkaline vapours acting on 

 test paper. 



For the analysis 1-638 gr. of the original mud was taken, con- 

 taining 1-541 gr. of dry. This quantity of matter furnished 3'^'' 

 of gas measured at 19°, and under a pressure of 0-7565, which 

 correspond to 3-43 millims. of nitrogen for 1-638 of original matter, 

 or 2-22 for 1000 of dry matter ; the original matter contained there- 

 fore 2-10 of nitrogen in 1000. These numbers show that the mud 

 of the Nile approaches very fertile lands. 



The incineration of the matter dried at 105° C. in vacuo for three 

 hours indicated 4*75 of organic matter in 100 parts, or 4*75 for 1000. 

 This organic matter contains then 4'67 of nitrogen in 100 parts. 



The matter soluble in water was extracted in order to ascertain 

 the nitrogen which it contained ; the results were as follow :— 



