Hints Regarding the Care of the Microscope 123 



the handkerchief. Undue pressure must not be used, but 

 it must be thoroughly cleaned. If oil should become dried 

 on the front lens at any time, it will be best to place some 

 fresh immersion-oil over it ; it should then be allowed to 

 stand in a place free from dust for about an hour, when 

 the whole may be cleaned off together. 



Travelling. — When travelling with a microscope it is 

 always well to pack the instrument round with tissue-paper, 

 so that it cannot shake in its case. Screws frequently be- 

 come loosened, and in some instances broken, and move- 

 ments disordered, by severe shaking while in transit. 



For a more exhaustive treatment of the subject the 

 following text-books are recommended : 



Carpenter's ' The Microscope and its Eevelations,' edited 

 by Dr. Dallinger. 



' The Microscope,' by Dr. Henri van Heurck. 



' Photo-micrography,' by Dr. Spitta. 



' Photo-micrography,' by Mr. Andrew Pringle. 



And as periodicals the best are : Knoivledge, published 

 by Messrs. Witherby and Co., 326, High Holborn, W.C. ; 

 Science Gossip, published at 110, Strand, W.C. ; the Journal 

 of the Royal Microscopical Society, published bi-monthly, and 

 the Journal of the Quekett Cluh, published twice a year, 

 both at 20, Hanover Square, W.C. 



