280 



CONTRIBUTIONS TO MICRO-MINERALOGY. 



ciple of Microscope in 1850 through Dr. Leeson, who, 

 during- the summer months of that year, had his large Micro- 

 scope altered by Messrs. Smith and Beck to the form claimed 

 by Professor Smith, for the purpose of prosecuting, during the 

 winter months, some micro-crystallographical researches ; and 



Fig. 3. 



on lately referring to Messrs. Smith and Beck's, their account- 

 books showed that the altered instrument had been delivered on 

 October 2bfh, 1850. On the same day that it was sent home, I 

 recollect that I went down to Greenwich with Dr. Leeson 



