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SMITHSONIAN MISCELLANEOUS CO'LLECTIONS 



VOL. 54 



These figures are of no present importance, for the supposed difficulty 

 of dehydration, in the light of more recent investigations, seems to be 

 imaginary. 



In 1892 tlie posthumous notes of the late Hoskyns-Abrahall were 

 edited and published by Ewan and Hartog.^ This chemist especially 

 studied the ratio between boron bromide and silver, and also redeter- 

 mined the percentage of water in crystallized borax. The latter work, 

 which was purely preliminary, although carried out with great care, gave 

 the following results, reduced to a vacuum standard : 



NanB^OTlOHiO. Na^B^O.,. Per cent. H^O. 



7.00667 3.69587 47.2069 



12.95936 6.82560 ' 47.3308 



4.65812 2.45248 47.3504 



4.47208 3.93956 47.2763 



4.94504 2.60759 47.2686 



Hence B = 10.702. ^«^^' 47.2866, ± .0171 



Two sets of determinations were made with the bromide, which was 

 prepared from boron and bromine directly, freed from excess of the 

 latter by standing over mercury, and finally collected, after distillation, 

 in small, weighed, glass bulbs. It was titrated with a solution of silver 

 after all the usual precautions. The first series of experiments was as 

 follows, with BBr3 proportional to 100 parts of silver stated as the ratio : 



Mean, 77.449, ± .0053 



This series of data is regarded by the editors as preliminary, and not 

 entitled to much consideration. The second series, which follows, was 

 the final one; both represent vacuum standards: 



' Journ. Chem. Soc, 61, 650. 



