INTRODUCTORY REMARKS. 29 



is only necessary to state, that we have now displayed 

 to us minute crystals, with a brillancy and richness of 

 colouring that is quite inconceivable. We see the smallest 

 difference in their thickness marked by some exquisite 

 change of colour ; whilst the beautiful black cross in the 

 circularly arranged crystals of zanthate of ammonia, and 

 the cross with the coloured rings in the compound of phos- 

 phoric acid and borate of soda, &c. &c. excite our admi- 

 ration beyond all bounds. These newly-discovered phe- 

 nomena, after a patient investigation, may lead to results 

 highly interesting, and of great importance to science. 



By a simple modification of its polarizing apparatus, 

 the microscope becomes of great value in investigating 

 some of the physical properties of matter : it is capable 

 of being constituted a complete polariscope, and made to 

 exhibit the phenomena of polarization in plates of crystals 

 cut perpendicular to their axes ; for instance, the coloured 

 rings, the black cross, the tints of unannealed glass, of 

 amethyst, &c. 



When relaxing from the stern pursuit after the exi- 

 gencies of life, where, perhaps, we may have been in- 

 dustriously labouring to benefit the -condition of our- 

 selves or families, what a delightful and inexhaustible 

 source of amusement is ever open to us where a good 

 microscope is at hand ! It is not always an easy task to 

 find innocent amusement : to find it blended with im- 

 provement is to find it indeed. We may, it is true, be 

 entertained by the veriest trifles in life, but we shall soon 

 grow weary of them ; and even the converse of intimate 



