62 On Bo7iny castle's Tngoyiometrtj. 



This gentleman writes ostensibly to correct my ^' errd* 

 neous statements," and yet does not point out one such er- 

 roneous statement. He cavils, it is true, at my asserting 

 that every part of Mr. Bonnycastle's work bears evident 

 marks of the same hand ; and affirms, that such an assertion 

 ** could not possibly have been made had the writer seen his 

 treatise." Now, the fact is, I had seen it : I was one of the 

 few persons who purchased Mr. Keith's book in 1801 ; and 

 one of the comparatively many of that few who have been 

 much disappointed on perusal, finding the work to give 

 no adequate representation of the science of trigonometry as 

 it now exists. I did not turn aside to speak of Mr. Keith's 

 book when I was reviewing Mr. Bonnycastle's ; but this 

 gentleman now compels me to say, that, although his work 

 may exhibit traces of his industry, it displays little else. I 

 must likewise remark, that the assertion with which he 

 quarrels is perfectly correct; for, although Mr. Bonnycastle 

 may have selected many of his examples from other authors 

 (and he would know little of the value of time if he endea- 

 voured to frame a complete set of new ones himself), he 

 lias, especially in the spherical trigonometry, modified all 

 their solutions according to the ten commodious and judi- 

 cious rules he has given at pages 80, 102, and 121, which 

 comprehend the whole doctrine of that branch of the science. 



The charges which Mr. Keith has adduced against Mr. 

 Bonnycastle it is not my immediate business to refute. I 

 may remark, however, that Mr. Keith's principal celebrity 

 arises from his prevailing habit of advancing insinuations of 

 plagiarism, or incapacity, against every author whose cha- 

 racter he feels inclined to attack ; from those of Horsley, 

 Maskelyne, and Vince, down to the lowest scribbler who 

 falls in his way. As to his accusations against Mr. Bormy- 

 castle, on page 330 of your last number, I will assert most 

 positively in general terms that they are not correct. No two 

 performances on the same subject can be less alike than the 

 two now spoken of. Mr. Bonnycastle may probably have 

 taken some practical examples from Mr. Keith's book ; but 

 not two, I may safely affirm, which contain any essentially 

 new principle; and a great proportion of what he may have 



taken 



