Ixx GENERAL SUMMARY OF SCIENTIFIC AND 



CHEMISTRY. 



By GEORGE F. BARKER, 



Professor of Physics in the University of Pennsylvania, Philadelphia, 



In General Chemistry^ Cayley has commumcated to the Chemical 

 Section of the British Association a paper on the analytical figures 

 which are called trees in mathematics, and on their application to 

 the theory of chemical compounds. His purpose was to determine 

 the theoretical number of hydrocarbons of the formula CH2^^2t 

 and his results agree with those of experiment so far as the latter 

 have been developed. He shows, for example, that 799 isomers are 

 possible, having the formula C^jH^g. 



Berthelot has continued his studies in thermo-chemistiy, and has 

 published two papers. In the first of these he treats of the thermal 

 changes connected "U'ith the oxides of nitrogen ; in the second, of 

 the thermic formation of barium dioxide and hydrogen dioxide. 



Muir has given his views of the jDresent system of chemical nota- 

 tion and its complete significance, arguing that its symbols actually 

 do mean far more than they are usually made to in ordinary usage, 

 and hence that the newer dynamical views now arising may find it 

 best to retain them. 



Janovsky has published a paper on equivalence, in which he 

 maintains with good reason that the only rational basis for this 

 property of atoms, as well as for the correlative one of combining 

 weight, is to be found in the dynamical theory of work. 



During the month of April a national chemical society, with the 

 title of the American Chemical Society, M\as organized in New York. 

 The objects of this body are the encouragement and advancement of 

 chemistry in all its branches, in furtherance of which monthly meet- 

 ings will be held in New York, and an annual meeting at some 

 selectetl place. The society starts with a membership of 133, under 

 the presidency of Professor J. W. Draper. 



Mills has published an important paper on " The First Principles 

 of Chemistry," in which he places in a strong light the dynamic 

 theory of chemistry in distinction from the statical theory now gen- 

 erally received. 



Lodge has given an interesting discussion on nodes and loops in 

 connection with chemical formulas, showing that the number of 

 each may be easil}^ calculated in any given case. 



Ostwald has experimented to determine the efiiect of mass in the 

 chemical action of water upon other bodies. He used a solution of 



