OUR BOOK SHELF. gt 

Manchester Microscopical Society Mr. H. P. Aylward exhibited a 
form which we can conscientiously recommend to all beginners, 
and a somewhat similar pattern of the same degree of excellence 
was exhibited by Mr. E. Ward at the March ordinary meeting of 
the same Society. Several important alterations have been carried 
out by both exhibitors. In Mr. Ward’s pattern the stand has been 
raised to allow of greater space beneath the stage, for greater con- 
venience of illumination, and this is also furthered by the addition 
ofa crank-arm to the mirror. The greatest advantage of this stand 
is however in the increased diameter of the optical tube, which 
allows of the use of the large oculars of Ross and others, and this 
tube is also supplied with an adapter to carry Zeis’s and other 
foreign oculars. The draw-tube is made to extend to a length of 
ten inches. The stage is made to revolve; it is of glass and a 
wheel of diaphragms revolves close to the surface, and the carrier 
for substage accessories is cut away on one side to allow of exces- 
sively oblique illumination. 
Mr. Aylward’s model has an enlarged foot, so that the stage is 
three-quarters of an inch higher than the illustration in our issue of 
September last, and the foot is made to extend further back so as 
to give greater steadiness when the body is placed in a horizontal 
position. The larger stand gives plenty of room for substage 
accessories, and a crank arm is also supplied to the mirror. ‘The 
rackwork has also been cut lower than in the form already illus- 
trated so that objectives of greater focal length may be used. The 
tubes of Mr. Aylward’s instrument are made to take Ross’s full size 
eyepiece, and an adapter is supplied to take any purchaser’s 
oculars, . 
We feel sure that in the absence of a standard gauge for eye- 
pieces, students could not do better than inspect these forms. 
Each of these instruments is adapted to all the requirements of the 
microscopist ; they are cheap, and may be purchased either with 
or without oculars and objectives. 

OUR: BOOK. SHELF: 
PorTFOLIO oF Drawincs and Descriptions of Living organisms 
sent out by THos. Botton, F.R.M.S. London, David Bogue. 
N6.27....17 plates, 

Mr. Bolton’s portfolio of drawings has now reached its seventh 
number, and is perhaps one of the most interesting of the series. 
In the Vegetable Kingdom we have illustrated :—Bacteria, 
Asterionella formosa, Surirella bifrons, Pleurosigma angulatum, 

