336 Prof. 0. Reynolds on certain Dimensional 



of the Royal Society, 1ST!). Mr. Fitzgerald courteously put 

 his remarks in the form of questions, expressing the hope that 

 I would answer them. 1 was prevented by other work from 

 preparing any thing in time for insertion in the April number; 

 but I now ask your space for a few remarks. 



The objections taken by Mr. Fitzgerald to my work may be 

 summed up as three : — 



(1) That by dividing space into eight regions I have adopted 

 a method which is at once inelegant and unnecessarily elabo- 

 rate. 



(2) That I have omitted terms which, if retained, would 

 have altered the results. 



(3) That I have changed my views and adopted the theory 

 which I had previously combated. 



To all these accusations I would most emphatically plead 

 not guilty. And I would further suggest, in explanation of 

 Mr. Fitzgerald's difficulty, (1) that he has not paid equal 

 attention to all parts of my paper, but has rather confined his 

 attention to those parts which relate to the phenomena of im- 

 pulsion, in wdiich he seems to be especially interested, and 

 that thus he has failed to see that, in order to obtain any 

 results whatever for transpiration, the division of space into 

 regions is necessary ; and (2) that in his anxiety to find a dif- 

 ferent result in the case of impulsion from that which I had 

 obtained, he has failed to perceive that the terms which I have 

 neglected, and of which he instances one as disproving my 

 conclusion, are of a distinctly smaller order of magnitude than 

 those which appear in my result. 



As regards, then, the charge of inelegance, I am sure that 

 Mr. Fitzgerald would not for one moment have urged it had he 

 not thought that the particular step to which he objects might 

 be replaced by some other known method. One might as well 

 abuse David because he used a stone and sling, as object to the 

 inelegance of a mathematical method by which alone true 

 results have been obtained. Of course I do not for one mo- 

 ment defend my method as being elegant, nor should I have 

 noticed this remark were it not that, taken together with the 

 more definite criticism to the same effect, it shows conclusively 

 that Mr. Fitzgerald has failed to notice the gist of the greater 

 portion of my paper — that he has failed to notice one of the 

 most important terms in the equation of transpiration and the 

 manner in which this term enters. In the paragraph begin- 

 ning at the bottom of page 104 he says, " With the symbols 

 and notation I have no fault to find ; but I must enter a pro- 

 test against his elaborate and totally unnecessary division of 

 space into eight regions. He might have perfectly well calcu- 



