June 1, 1869.] 



HARDWICKE'S SCIENCE-GOSSIP. 



139 



MICROSCOPY. 



Vulcanite Cells. — I have lately had a supply 

 of "Vulcanite Cells from Messrs. Pumphrey, of 

 Birmingham, and I can safely say they are the 

 best cells that I have used for mounting objects, 

 dry or in fluid, being far superior to tin or glass 

 cells, as in change of temperature there is no give 

 in glass or tin, and the cement cracks ; but here we 

 have a substance in every way suited to the wants 

 of the Microscopist, as the cells can be had in 

 various sizes, as slides 3 x 1, perforated with any 

 sized holes, and also as discs to mount opaque 

 objects on, or to act as a stop to the Lieburkuhn. 

 I have until lately used cells made of the vulcanized 

 rubber, but these had some disadvantages which 

 are overcome by the Vulcanite Cells. I find, in 

 cementing them to the glass slide, a scratch with a 

 fine file on the polished surface causes the marine 

 glue to hold very firm, and also the top side when 

 cementing down the glass cover ; they can also be 

 ground down to any thickness required by 

 reducing them with a file first, and finishing off on 

 a flat surface to obtaiu the cell perfectly level to 

 receive the glass cover.—/. E. Turner. 



Bacillaria paradoxa.— Prom the latter part 

 of your reply to "T. S.'s "query, page 72 of the 

 March number of Science-Gossip (a periodical not 

 sufficiently known in this country), it would appear 

 that you doubt the presence of Bacillaria 

 paradoxa in fresh water. The following may 

 therefore interest you and your readers: — In 

 December, 1861, I found the Bacillaria paradoxa 

 most plentiful in gatherings from a running stream 

 about two miles from Ahmednugger (Bombay 

 Presidency). Now Ahmednugger is about a 

 hundred and thirty miles from the sea as the crow 

 flies, and some sixty miles from the high range of 

 ghauts dividing the Deccan, or High Land, from 

 the Concan, or Low Laud. I have since found it in 

 abundance in the ditches near Poona, which is also 

 above the ghauts ; so that I consider it is an 

 established fact that this diatom is to be found in 

 fresh as well as salt water ; in short, I have never 

 found it in any estuary or brackish water, but 

 always in fresh water. At page 148 of the April 

 (1862) number of the Quarterly Journal of Micro- 

 scopical Science, the Rev. R. Douglas mentions 

 having found this diatom in ditches near the river a 

 short distance above the town of Stafford. I cannot 

 but think that the specific title of- Militaris 

 would be better suited for this beautiful and most 

 peculiar diatom; for never have I seen a better 

 representation of the movements of a regiment 

 deploying into line and re-forming column, than [in 

 the unaccountable movements of this diatom. — 

 Julian Hobson, Major HM. Bombay Staff Corps, 

 Mhow, Bombay Pres., India. 



Drawing from the Microscope. — In the 

 April number of Science-Gossip, your correspon- 

 dent W. Scantlebury gives a very useful suggestion 

 under the above heading. I have for some time 

 employed means somewhat similar for projecting 

 the magnified image of an object on paper, but with 

 this important difference :— instead of the special 

 apparatus described by your correspondent, I use a 

 Wollaston's Camera Lucida fixed over the eye-piece 

 in the usual way, only reversed j that is, the flat part 

 of the reflector turned down instead of up. The 

 size of the reflected image can be varied by altering 

 the distance between the reflector and the paper on 

 which the drawing is to be made, of course re- 

 focussing for each change. The great difficulty I 

 experience is in obtaining a sufficiency of light to 

 delineate clearly the details of structure. I use a 

 one and a half inch objective (Beck's), and condense 

 the rays of light through a large bull's-eye. It is 

 very important to exclude all extraneous light, for 

 which purpose I use a sort of screen, made of pieces 

 of millboard, and which, placed round the micro- 

 scope and the lamp, forms a kind of dark chamber 

 for the projected image to fall on the paper. Per- 

 haps some of your correspondents may be able to 

 suggest means of intensifying the light to a greater 

 degree than can be obtained either with the mirror 

 or the bull's-eye, although I consider the latter, care- 

 fully adjusted, superior to the former. In using 

 the Binocular Microscope, the prism must of course 

 be drawn back so as to allow the whole rays from 

 the object-glass to pass into the straight body. — W. 

 E. B., Sicansea. 



The State Microscopical Society of Illinois. 

 — We have received a copy of the Act incorporating 

 this society. At p. 54 we announced its establish- 

 ment at Chicago, and congratulated the promoters 

 on their success, which we hope will be continuous. 

 They have the heartiest wishes of their Anglican 

 cousins and fellow-students. 



Norfolk and Norwich Naturalists' Society. 

 — We are glad to see our Norwich friends so 

 vigorous and hopeful in starting this new society. 

 It commences under the presidency of the Rev. 

 Joseph Cromptou, and with our friends H. Steven- 

 son, P.L.S., the author of the "Birds of Norfolk," 

 and P. Kitton — a name familiar to readers of this 

 journal — as vice-presidents. The appearance of 

 other names on the executive, well known for their 

 earnestness and perseverance, assures us that they 

 intend to succeed, towards which consummation we 

 wish them " good speed." 



Poraminifera. — The bibliography of Poramiui- 

 fera is now being published in consecutive num- 

 bers of the Journal of the Quekett Microscopical 

 Club. 



