THE MICROSCOPE. 205 



PHOTOGRAPH SLIDES. 



A large variety of very beautiful photograph slides may be 

 made for a small sum in the following manner: Purchase for one 

 dollar a dozen a lot of the photograph charms such as are mounted 

 in small ivory holders and intended for watch-chain charms. Re- 

 move the small lens from the ivory holder, and on examination it 

 will be found that the photograph is on a bit of thin glass which is 

 cemented to one end of the small lens. First place a tiny drop of 

 balsam on a small cover-glass with the point of a needle and place 

 the cover on one end of a strip of mica. Next take hold of the 

 photograph end of the charm with a pair of tweezers, hold the other 

 end for a moment in the flame of an alcohol lamp, and the lens part 

 will drop off. Place the bit of thin glass, photograph side down, on 

 the balsam on the cover, and move the mica slowly back and forth 

 over the alcohol flame until the balsam becomes hard and the pic- 

 ture secure, taking care not to burn the balsam or to smoke it. Now 

 prepare a cell with a curtain ring and white zinc cement and mount 

 the cover in it. Finish in as ornamental a way as desired. The 

 white zinc may be finished with the colored ink circles if desired. 

 Asphalt, brunswick black or india ink may be put on the under side 

 of the cover-glass next the picture after the balsam has been dried 

 over a lamp, and neither one will run under the picture. Heat will 

 not injure the photograph. 



MOUNTS WITHOUT COVERS. 



Many beautiful objects for the lower powers require no cells 

 and no covers. Among them may be mentioned flower seeds, the 

 head and other portions of the Spanish fly, etc. Place the slide on 

 a turn-table and with white zinc turn a disk on the center and an- 

 other with asphalt in the center of the white one. With a fine brush 

 arrange flower seeds in any pattern desired by picking them up with 

 the point of the brush after drawing it between the lips, then lay 

 them down on the black center. When dry the cement will hold the 

 objects in position. Few more beautiful objects can be found than 

 the heads of Spanish flies, which may be procured at drug stores and 

 mounted in the same way. The disks may be finished with colored 

 rings if desired. No covers will be needed. 



ARRANGING DIATOMS. 



Those who wish to arrange diatoms will find the following of 

 great assistance: With a pipette place the diatoms on a film of 



