1883.] 



MICROSCOPICAL JOURNAL. 



135 



sustain his position, and they are con- 

 clusive as to the facts, whatever the 

 exph\nation may be. 



We may add that all objectives do 

 not bear a reduction of aperture with- 

 out loss of definition. In a few cases 

 it has been found that the shutter can- 

 not be used with them. But such 

 cases are quite rare exceptions to the 

 general rule. For example, a Wales's 

 ij-inch of 30,° would scarcely stand 

 any reduction. We believe this is also 

 the case with some of the objectives 

 of Zeiss that have been tried. 



Mounting with Wax. — Mr. Jno. 

 E. Fawcett has described the follow- 

 ing method of using wax in mounting, 

 in the Microscopical News: — 



My process is to get a spirit lamp 

 and place it under a dish supported 

 on a retort stand. Into the dish I 

 pour white wax, or bees wax, and melt 

 it. It requires making very hot, and 

 the lamp to be left continually under 

 the dish. If the slide is to be opaque, 

 I cut a piece of black paper to about 

 the size of the cell to be made, and 

 attach it to the slip. I then put it on 

 the turn-table, and build up the cell 

 with the hot wax. Of course it is al- 

 lowed to overlap the paper background 

 and the glass, and thus make a neat 

 cell. It has the advantage of being 

 built up to any thickness at once. 

 There is also no untidiness of the 

 paper not fitting the bottom of the 

 ordinary vulcanite cell, or if it is 

 placed on the underside of it, being 

 scratched off. Then again, if the 

 background is put at the back of the 

 glass slip, it is invariably bright instead 

 of dull. When the slide is dry and 

 ready for sealing up, all that is neces- 

 sary is to place the cover on it and put 

 it once more on the turn-table, when 

 one turn, with the application of the 

 wax brush, is sufificient to make it a 

 permanent mount. It can then be 

 finished with the usual varnishes. I 

 have described it for opaque dry 

 mounts, but the process can be equally 

 well used with transparent dry mounts. 



I also use the wax to help to till up the 

 sides of balsam cell-mounts, between 

 the closing cement and the finishing 

 varnish. In adopting this plan, the wax 

 must be kept very hot, and the brush 

 should be left in it when not in use. 



The American Society of Micro- 

 SCOPISTS. — Being so far away from 

 home when writing these few words 

 about the August meeting of the So- 

 ciety, merely to remind our readers of 

 the meeting, and to urge upon them the 

 advantages which are oftered by gath- 

 erings of the kind for social inter- 

 course, as well as for the interchange 

 of ideas between persons from differ- 

 ent parts of our great country, we are 

 unable to give any particulars con- 

 cerning the meeting this year. Prof. 

 McCalla, the President, informs us 

 that the meeting promises to be a 

 very large one. We trust it will be. 

 The State Microscopical Society of 

 Illinois has a large number of mem- 

 bers who will, we are confident, do all 

 in their power to make it a success, 

 and to extend Western hospitality to 

 all visitors — may we say even to 

 those from St. Louis, the only rival 

 which Chicago fears ! 



Although we cannot be present at 

 the meeting, we will endeavor to re- 

 port the proceedings promptly in 

 these columns, as has been our cus- 

 tom heretofore. 



Synopsis of Diatoms. — The plates 

 of this excellent work of Dr. Henri 

 Van Heurck, are now all published 

 and in the hands of subscribers. Con- 

 sidering the nature of the illustrations, 

 and the labor it must have required 

 to collect and arrange the material 

 for them, we would congratulate the 

 author for having completed the work 

 so quickly, and in such a satisfactory 

 manner. Subscribers will notice that 

 there is still a volume of text to come. 

 The most we can say about that, is 

 that it is to be published next year. 



Meanwhile Dr. Van Heurck is en- 



