96 



THE AMEKICAN MONTHLY 



[May, 



The best cements to apply for secur- 

 ing the cover, as described above, 

 are the balsam or the shellac. After 

 either of these is used, it is advis- 

 able to finish the slides with as- 

 3)halt. We do liot advise the em- 

 ployment of other cements for this 

 purpose. Nothing looks so well as a 

 Hack ring around mounts of this 

 iind. The colored rings are pretty, 

 iDut they are more suitable for larger 

 and deeper cells. It often happens 

 that the cement does not form a 

 perfectly true, unbroken edge, 

 When this is the case, apply the 

 inife-blade, before the cement sets, 

 and turn the edge smooth and true. 



2. To mount objects opaque. 



Generally when objects are 

 mounted opaque, they are of such 

 a size as to require deeper cells 

 "than those described above, but the 

 cover is cemented on in the same 

 manner, so we will only describe a 

 few of the numerous kinds of cells. 



a. The Wax-cell. This can be 

 made of any thickness by punching 

 Tings out of several layers of sheet- 

 w^ax and attaching them to a slide, 

 using a piece of wax to form the 

 floor of the cell. Dr. Hamlin's 

 m.ethod (]5. 46) is a still better one. 



h. The Curtain-ring-cell. Cutout 

 a circular piece of wax, attach 

 it to the slide, place a curtain-ring 

 upon it, soften the wax by heat 

 until the ring is imbedded in it. If 

 the wax should become heated too 

 miuch, so as to lose its smooth finish, 

 another piece can be cut from a 

 sheet and pressed into the cell to 

 iorm the bottom. Objects can be 

 made to adhei'e to the wax by 

 hrushing it over with a little tur- 

 pentine, and attaching them before 

 the latter evaporates. 



c. The cement-cell. A good cell 

 can be made of asphalt by applying 

 the cement and turning it up with 

 the knife-blade. A still better one 

 can be made by a cement, which is 



known as shellac cement, used by 

 Mr. Merriman. The bottom of 

 cement-cells can be made opaque 

 by a coating of asphalt. It is evi- 

 dent that for the paraboloid or the 

 lieberkuhn, any of the cells can be 

 made transparent. 



For dry-mounts it is advisable to 

 finish with asphalt varnish. Be 

 careful to cement the cover down 

 with balsam or shellac first, then 

 there will be no danger that the 

 asphalt will run in. The asphalt 

 should be applied so as to come over 

 the edge of the cover, otherwise 

 the cover may come off when the 

 cement becomes hard and brittle. 



EDITORIAL. 



To Subscribers and Adver- 

 tisers. 



The subscription-list of the Jour- 

 nal is constantly increasing, and so 

 far as we know our readers gener- 

 ally, have been well pleased with 

 the articles we have published. 

 However, we do not hesitate to 

 make use of any criticisms or sug- 

 gestions that reach us, and, as we 

 stated some time ago, we would be 

 pleased to have our readers express 

 their desires freely, and thus enable 

 us to select such articles as they 

 want. 



Experience has taught us that 

 what microscopists most desire is 

 articles having a practical bearing, 

 and we are constantly trying to 

 furnish just such articles. To cite 

 a single example, the articles on 

 mounting, which are now being 

 2:)ublished, are practical in every 

 sense, and these are only one series, 

 which is to be followed by others 

 on other subjects of equal, if not 

 of greater, value and interest to 

 the amateur. 



Although this Journal does not 



