The President's Address. 
33 
new cheap microscope. Its action is like that of the mag- 
netic stage, but the requisite adhesion is obtained by suitably 
placed springs, which oppose a convenient resistance, and do 
not seem likely to get out of order. 
A simple adapter has been devised by Mr. Richards ; it 
consists of a tube which passes through the stage of the 
microscope, and is sufficiently long to reach within focussing 
distance of the bottom of the stand, thus enabling an observer 
to view objects on a level with the base of the instrument, 
or to perform manipulations on the table. 
A paper was read by the Rev. J. B. Reade, describing 
some improvements on his former “ Kettledrum Illuminator.” 
By superposing another somewhat smaller hemispherical 
lens, he is thus enabled to extend the angular aperture of the 
illuminating pencil to its utmost limits, and the large area of 
the lenses gives a great quantity of light. By the addition of 
ingeniously contrived shifting apertures and stops of various 
forms, he is enabled to throw light on the object from every 
angle, either in one or in several directions together, or to 
entirely obscure the central rays for viewing objects with 
dark-field illumination. This contrivance of Mr. Readers 
affords a very slanting illumination, and its want of achro- 
maticity is stated by him not to interfere with the particular 
purposes for which it was designed. 
To obtain oblique illuminations in two directions for the 
display of the Pleurosigma rhomboides , Mr. Newton Tomkins 
has employed two prisms and two sources of light, arranged 
at right angles to each other, with excellent effect. 
At our last meeting a new form of field microscope, con- 
structed by Mr. Baker, was described by Mr. Newton Tom- 
kins. This appears far to exceed, both in portability and 
simplicity, anything that has yet been produced. Two of 
the legs are jointed from a position near the eye-piece of the 
instrument. The body itself virtually forms the greater part 
of the length of the third leg, and is thus set at a very 
suitable angle of observation. The arrangement is remark- 
able for extreme steadiness, and the stage and mirror, being 
low, make the instrument very handy for manipulation. 
The legs are removable for the purpose of containing tubes 
and other apparatus. These advantages, together with the 
low price at which the microscope is manufactured, are good 
reasons why its employment should become universal. 
This instrument seems to be an improvement on one of 
somewhat similar construction exhibited by Mr. Highley at 
the last soiree of this Society. 
The art of making photo-micrographs with very high 
