18 MICROSCOPY. 
Microscopy. 
i 
Having lately had the privilege of using one of the new Oil 
Immersion 4th, made by Zeiss, of Jena, from calculations of Professor 
Abbe, and on a design of Mr. Stephenson, F.R.M.S., [See Vol. I. (1878) 
Journal of R.M.S8., p. 51,] I would strongly urge on all who can afford to 
buy one to order a glass forthwith. Ihave been engaged during part of 
this year in examining slides of the mastax of Melicerta ringens, sent to 
me by the Rev. Lord Sydney G. Osborne, and have written a paper on 
them, which has been published in the current transactions of the Royal 
Microscopical Society ; but, unfortunately, I had not had, before writing 
my paper, the privilege of viewing the slides through this Oil Immersion 
ath. I have since had that privilege, and I must almost re-write the paper, 
It is simply a magical instrument for bringing out structure for a 
laminated surface, which, under an ordinary ith, looks not merely trans- 
parent, but empty of superficies, like a window-frame with the glass out, 
becomes under this glass one mass of fine lines. Parts of the mastax of 
Melicerta, which I had treated like unoccupied frames, are seen under 
this power to be “ full of matter ”—that is to say, solid areas of transparent 
texture. The glass will not supersede the ordinary ith, because it is useless 
for such intermediate fluids as water; but for all objects immersed in 
the ordinary fluids used in mounting objects for the microscope, it will 
be found to be a great addition to our instruments. This specimen glass 
was lent me by Mr. Frank Crisp, Secretary R.M.S., who, I believe, has 
been amongst the first observers who have realised the value of the new 
power. ‘To gentlemen engaged in the study of tissue and minerals, or, 
indeed, of any transparent objects which will bear immersion in balsam, 
this glass will prove of great importance.—F. A. BepwrLu 
At a recent meeting of the Birmingham Natural History and 
Microscopical Society, Mr. H. E. Forrest exhibited and described a 
simple and easy method of drawing objects under the Microscope. The 
apparatus consists of a three-sided prism, fitted to slide on to the eye- 
piece of the Microscope, and capable of being adjusted to any angle. The 
Microscope is put in a horizontal position, and the light thrown by a 
condenser straight up the tube. The lamp is enclosed in a box or 
cylinder, with a hole on one side the size of the condenser, in order to 
shut off all unnecessary light. The room being darkened, the image of 
the object is seen thrown on to the paper placed underneath, and has 
merely to be traced over with a pencil. The size of the drawing is 
governed by its distance from the prism; the rays diverge, consequently 
the further the paper from the prism, the larger is the picture; and 
by placing the paper on the floor, an image may be drawn 4ft. or 5ft. 
in diameter. The advantages claimed for this little instrument by Mr. 
Forrest are simplicity, cheapness, and superiority to the camera or 
neutral tint glass, in that it really throws the image on to the paper instead 
of only apparently doing so. As seen in operation at the meeting, one 
disadvantage was apparent. The loss of light was so great that it was 
