1881.] 



MICROSCOPICAL JOURNAL. 



17 



croscopical Society does not fill, and we 

 predict for The Northern Microscopist 

 immediate prosperity. " Its aim is to 

 keep a record of the proceedings of 

 the chief Microscopical Societies in 

 the North, and so furnish the individ- 

 ual member with at least as much 

 information as he would obtain if the 

 Society to which he belonged pub- 

 lished its own transactions — may be 

 more." 



We congratulate the Editor upon 

 the excellence and interest of his in- 

 itial number. It contains 24 pages 

 and one plate. 



o 



Abbe's Binocular Prism. — It 

 seems to be a rather difficult mat- 

 ter to introduce an improvement 

 in the microscope, which has not 

 been anticipated by some plan of 

 Mr. F. H. Wenham, to whom we are 

 indebted for so many useful acces- 

 sories. It now appears that a bin- 

 ocular prism, in some respects, iden- 

 tical with that of Prof. Abbe, which 

 was described in a recent number of 

 this Journal, was devised by Mr. 

 Wenham in the year 1866. (See 

 Trans. R. Micro. Soc, Vol. XIV, 

 p. 104.) 



Professor Abbe has since ac- 

 knowledged that the plan of dividing 

 the rays was original with Mr. Wen- 

 ham, although he was not aware that 

 Mr. Wenham had employed it when 

 his article was written. However, the 

 credit of having made a satisfactory 

 application of the principle to pro- 

 duce stereoscopic vision, seems to be- 

 long to Prof. Abbe. 



The principles involved in pro- 

 ducing the stereoscopic effect by the 

 new eye-piece, will be more fully 

 elucidated in a future number of this 

 Journal. 



o 



Beading on Diatom-frustules. 

 — From some remarks recently made 

 before the Royal Microscopical So- 

 ciety (London), we infer that the 

 question whether or not there is a 

 beaded structure to be observed in 

 the markings of Frustulia Saxonica, 



is likely to be opened for discussion. 

 We would like to hear from Dr. 

 Woodward on the subject once more. 

 He has contended that there are no 

 longitudinal lines on that diatom. 

 At a meeting of the Royal Micros- 

 copical Society, Mr. T. Powell showed 

 the A. pellucida, mounted dry on the 

 cover, by the vertical illuminator ; 

 and this method of illumination 

 showed a beaded structure on the 

 valve. The new ^ homogeneous im- 

 mersion objective was used. 



CORRESPONDENCE. 



To THE Editor: — The following is a 

 simple method of making wax-cells, which 

 may not be new, but which I have not yet 

 seen described in any journal. The bot- 

 tom of the cell may be punched from pa- 

 per or wax as preferred. One of these is 

 fixed in the centre of a slide on the turn- 

 table and with a brush moderately full of 

 hot melted wax, a ring is made in the same 

 manner as when an ordinary cement is 

 used, and successive coats applied until 

 the necessary size is attained. To remove 

 the brush-marks, heat a small screw-driver 

 or any other similar object that is suflficient- 

 ly thick to retain its heat long enough, and 

 with this mould and smooth the cell to 

 the desired shape. 



If preferred, the cell can be coated with 

 any cement to prevent sweating. The cover 

 may be fastened with the brush and hot 

 wax, or in any way preferred. If not ce- 

 mented a cell can be completed in two or 

 three minutes' time. 



C. Blasdale. 



NOTES. 



— An English gentleman has devised a 

 cheap and convenient arrangement for ex- 

 hibiting the organisms of pond-life. It con- 

 sists of a circular glass disc, revolving 

 upon a central pin, which is attached to 

 the microscope by means of a cross-piece 

 which fits the stage. Near the periphery 

 of the disc a number of cells are built up 

 so that cover-glasses may be applied with- 

 out crushing the objects. A spring is also 

 attached to the cross-piece and reaches to 

 near the centre of the disc.where it catches 

 in some notches which correspond to the 



