Till-: GAMMA, OR FACTORIAL, FUNCTION. 647 



D. Legenclre's Coefficient in S}>herical Harmonic 



ics 



P = Ji^ D" (i"t"'\ 

 " Tin ^^ y^ ^ ' 



where / = sin^fl/2, /' = cos^«/2, and ;/ has anv value. Ako, if cos 6 

 IS positive, 



I p" 

 P»=2^l f/^ . (cos f>+« sin ft COS </))-"-' 



E. Laplace's Coefficient is 



(constant) Dj'±"' | /"/'« | 



F. The Hypergeometric Series can be written 



D-{x^'{i-xy] or ^(;//)„_,(//), 



x^ 



Physical Chemistry.- Prof. H. E. Armstrong, in a 

 thorough! V cliaracteristic spet^-h in Alelbonrne, about two years 

 ago, said that physicists have unfortunately in the past held 

 aloof from cliemists, and therefore the movement now in pro- 

 gress is to be welcomed, for its effect must be to lead the two 

 parties to work together to a common end. Parenthetically, 

 however, he observed that the views now advocated by physicists 

 are entirely different from any conceptions that chemists have 

 ever entertained, and hence are not easily assimilable. A cay 

 or two previously Prof. W. J. Pope had also referred to the 

 sharp divergence between the chemistry and the ])hysics of twenty 

 years ago, and had remarked on the interesting fact that tlie two 

 sciences were now again converging, for many purely chemical 

 questions had received such full quantitative study that the results 

 are susceptible to attack by the methods of the mathematical 

 physicist; while the intense complication of many physical pro- 

 blems — problems whose intricacies the traditional mathematical 

 mode of attack of the physicist had proved powerless to deal 

 with — had led to their interpretation by the logical argument of 

 the chemist. A third of a century ago the present-day con- 

 ception of physical chemistry had no existence : since then a 

 flood of light has suft'used the very inward parts of chemical 

 structure, and stereochemistry has taken a most definite place 

 amongst the branches of chemical science. Physical chemistry, 

 widely extensive and deeply intensive as it is, has practically 

 moulded itself into the shape of a new science out of the coter- 



