1883.] 



MICROSCOPICAL JOURNAL. 



Si 



paper is then placed on the glass, and 

 the edge allowed to dip into the water. 

 Objects to be examined arc placed on 

 large cover-glasses. and either 

 covered with a smaller cover, or left 

 exposed. These cover-glasses are 

 laid upon the blotting paper and 

 covered with watch-glasses. A single 

 large watch-glass of ji inches diame- 

 ter may be used, or a number of small 

 ones, one for each specimen. Objects 

 can be kept fresh and moist in this 

 way, with far less trouble than by any 

 other method we have tried. 



The Movement of Diatoms. — 

 Mr. Jabez Hogg recently addressed a 

 communication to the Socie'te Beige 

 de Microscopic giving his views con- 

 cerning the cause of the motions of 

 diatoms, a rJsum: of which is pub- 

 lished in the Bulletin. The author 

 believes that the movement is caused 

 by very contractile, prehensile organs, 

 which are alternately projected and 

 retracted through openings of the 

 valves near the median nodule. 



Dr. Van Ermengem commented 

 upon the article by Mr. Hogg, and 

 stated that he had tried many experi- 

 ments with staining fluids, osmic acid, 

 absolute alcohol, etc., in the hope of 

 discovering the cause of the move- 

 ment, using the best objectives and 

 illuminating apparatus, but he had 

 failed to discover any apparent cause 

 of the motion in anv case. 



Plants in Water at High Tem- 

 peratures. — In a hot spring in Pue- 

 blo Valley, Humboldt Co., Nevada, 

 diatoms in great abundance were col- 

 lected by a Dr. Blake, living in water 

 at a temperature of 163° F. More 

 than fifty species were described from 

 the spring, mostly identical with species 

 found in infusorial earth in Utah. 

 Associated with the diatoms was some 

 red alga. 



In one of the hot springs at the 

 California geysers, at a temperature 



of 198° F. he found also two kinds of 

 Conferva, one species " resembling 

 Hydrococis Bischoffii, but larger ; the 

 other a filament with globular enlarge- 

 ments at intervals." In another spring, 

 oscillaria were found, growing at a 

 teniperature of 174°. 



An Evening with Amphipleura. — 

 One evening last month, at the invi- 

 tation of Mr. C. Van Brunt, a few inter- 

 ested friends met at his residence in 

 New York to examine the new iVinch 

 Spencer objective, which hedescribed 

 before the New York Microsopical 

 Society a few evenings before. The 

 test-object used was the A. peUudda 

 mounted dry, and the lens was com- 

 pared with several others by Tolles and 

 Zeiss. The exhibition of the dry A. 

 pcllncida given on that occasion was 

 exceedingly fine. The objectives 

 used for comparison were two one- 

 sixths and an eighth by Tolles, and two- 

 eighths and a twelfth by Zeiss, and the 

 aggregate value of the seven fine 

 objectives used, was calculated at 

 about $640.00, an amount which 

 indicates the high appreciation, on the 

 part of the owners, of the finest pro- 

 ducts of the optician's skill. 



The iV is, undoubtedly, one of the 

 finest lenses for resolution ever yet 

 produced. The only objectives that 

 compared favorably with it were the 

 sixths of Tolles. Between the Tolles 

 i and the Spencer -^i,-, there was 

 scarcely any appreciable difference ; 

 in fact, the difference was so slight 

 on the dry-mounted frustule, that we 

 prefer to withold any expression of 

 preference for one or the other until the 

 lenses are tested upon a balsam-moun- 

 ted shell. Both the \ and the -^V were 

 tested with oculars varying from a C. 

 Huyghenian up to a ^-inch solid, and, 

 we doubt not, either of them would have 

 borne a ^-inch solid ocular, had one 

 been at hand. We consider that by 

 the production of the new -iV, Mr. 

 Spencer has demonstrated his ability, 

 which many who have been acquainted 

 with his work have long known, to 



