years between 1783 and 1793, was in 

 the habit of making excursions with 

 Dr Charles Blagden, for the purpose of 

 tracing the succession and distribution of 

 the strata that underlie the southern 

 counties of England. Of these "Jour- 

 neys," as he called them, he made notes, 

 which have been preserved. The Caven- 

 dish MSSl, at the instance of the Cam- 

 bridge University Press, have been placed 

 by the Duke of Devonshire in the hands 

 of Sir T. Edward Thorpe, with a view 

 to the publication of the chemical papers 

 which they include. The collection of 

 manuscripts contains the letter from 

 Michell, together with the draft of 

 Cavendish's reply. This correspondence, 

 which throws an interesting light on the 

 condition of geological science in this 

 country during the last quarter of the 

 eighteenth century, is now published for 

 the first time 1 . 



1 Dr (afterwards Sir) Charles Blagden, who be- 

 came one of the Secretaries of the Royal Society in 



