HerschePs Approval. 167 



errors. The letter lie wrote on this occasion made 

 me so happy and proud that I have preserved it. 



LETTER FROM SIR JOHN HERSCHEL TO MRS. SOMERVILLE. 



DEAR MRS. SOMERVILLE, 



I have read your manuscript with the greatest 

 pleasure, and will not hesitate to add, (because I am sure 

 you will believe it sincere,) with the highest admiration. 

 Go on thus, and you will leave a memorial of no common 

 kind to posterity; and, what you will value far more 

 than fame, you will have accomplished a most useful 

 work. What a pity that La Place has not lived to see 

 this illustration of his great work ! You will only, I fear, 

 give too strong a stimulus to the study of abstract science 

 by this performance. 



I have marked as somewhat obscure a part of the 



illustration of the principle of virtual velocities 



Will you look at this point again? I have made a 

 trifling remark in page 6, but it is a mere matter of 

 metaphysical nicety, and perhaps hardly worth pencilling 

 your beautiful manuscript for. 



Ever yours most truly, 



J. HERSCHEL. 



[In publishing the following letter, I do not consider 

 that I am infringing on the rule I have followed in obedi- 

 ence to my mother's wishes, that is, to abstain from 

 giving publicity to all letters which are of a private and 

 confidential character. This one entirely concerns her 

 scientific writings, and is interesting as showing the con- 

 fidence which existed between Sir John Herschel and 



