Knowledge should be practical from the first. The student may 

 form gradually a small collection of specimens, and those will often 

 be most instructive which are collected by himself ; but in cases where 

 collection of specimens is not possible, it may be useful to mention 

 that 



MINERALS AND ROCK SPECIMENS may be obtained from Mr. GREGORY of 

 Charlotte Street, Fitzroy Square. 



COLLECTIONS OP SLICES OF MINERALS, ROCKS, AND FOSSILS for. the Micro- 

 scope are supplied by Messrs. How & Co., of Farringdon Street. 



Mr. CATTELL of Leighton Road, Kentish Town, is skilful in slicing rocks 

 and fossils for microscopic study. 



