acid 



M7G-7 



NOTE 



THE first edition of this work, consisting of 120 copies, 

 printed in 1888, has become so scarce that it was thought 

 advisable to issue a new and revised edition. 



Many important additions have been made, and special 

 attention might be called to the two issues of the first edition 

 of the Principia, to the two differently dated copies of the 

 second edition of the Optics, and to the six varying issues of 

 the Commercium Epistolicum, etc., giving information now 

 printed for the first time. 



It is hoped that the cordial reception given to the first 

 issue will be merited in this revised and enlarged edition. 



G. J. GRAY. 



October , igof. 



