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XXIII. Contributions to the History of the Phosphorus-Bases. 
By Augustus William Hofmann, F.B.S. 
[Received June 21, — Head June 21, 1860. 
SECOND MEMOIE. 
THEOET OE DIATOmC BASES.— DIPHOSPHONIUM-COMPOENDS. 
In surveying the rich harvest of discoveries which of late years have rewarded the 
exertions of chemists, with reference to their general effect on the progress of the science, 
we cannot avoid recognizing as one of the most valuable amongst their acquisitions, the 
development of the theoiy of polyatomic compounds. Seldom has a theory diffused a 
clearer light on preHously established facts, or exerted a more fructifying and inspiring 
influence on the labours of chemists. First coming into notice in the classical 
researches of Geaham and Liebig on the polybasic acids, and afterwards extended and 
generalized by the experiments of Geehaedt and Williamson, it has acquired in 
Beethelot’s beautiful investigation of Glycerin, a new field of discovery, the active 
cultivation of which has already brought to maturity a great variety of fruits. An im- 
portant step in the development of these ideas was made by H. L. Buff, in showing that 
dibromide of ethylene can be converted into a corresponding sulphocyanate, and in the 
conclusions which he drew from this observation, until, in the brilliant experimental 
researches of Wuetz on the diatomic alcohols, the doctrine of polyatomic compounds 
has received its clearest and most elegant expression. 
Considering the untiring activity with which chemists have devoted themselves to the 
study of the polybasic acids and, within the last few years, of the polyatomic alcohols, 
it cannot but appear remarkable that so little attention should hitherto have been 
bestowed on the polyacid bases. It is true that we are already in possession of many 
valuable observations relating to these bodies ; but they are isolated, and the facts which 
they have established can scarcely be looked upon as more than accidental acquisitions. 
Kegarded in the scientific sense as a class, and in their relations to other groups of 
bodies, the polyatomic bases have hitherto been left without examination. 
Kespecting the constitution of these compounds, and the conditions under which they 
would be produced, no doubt could be entertained. For, as from a single molecule of 
water, a monatomic alcohol, a monobasic acid, or a monacid base can be produced, 
according to the nature of the monatomic radical by which the hydrogen is replaced, so 
likewise must it be possible, by a proper selection of polyatomic radicals, to link two or 
more molecules of water, so as to fonn one molecule of a polyacid base, just as the in- 
troduction of other polyatomic radicals gives rise to the formation of polyatomic alcohols 
or polybasic acids. It remained only to submit these ideas to the test of experiment. 
MDCCCLX. 3 0 
