PROCEEDINGS OF THE SOCIETY. 
371 
method of doing the same thing. It would perhaps be remembered 
Mr. Hardy took an ordinary spot-lens and put behind it a series of 
coloured segments, and the effects which he produced in that way were 
certainly very beautiful, and his “ Chromatoscope, ’* as he called it, was 
very much admired at the time. This only showed that “there was 
nothing new under the sun,” but it did not in any way detract from the 
scientific value of Mr. Rheinberg’s work as described in his paper. 
Mr. J. E. Ingpen thought one of the most important things brought 
out by this method was its ability to show the coarser details of a diatom 
in the centre, and the finer details in the peripheral zone. 
Mr. Rheinberg expressed the surprise which he felt at hearing from 
Mr. Karop that the method introduced to their notice in his paper had 
been anticipated ; but he felt sure that those who had an opportunity of 
seeing some of the results already attained would agree that it was likely 
to be useful. At present only the theory had been worked out, but he 
was very sanguine in his belief that it could be most usefully applied to 
many purposes. The exhibits shown in the room that evening in illus- 
tration of the application of the method were, he regretted, not so good 
as those results which he had been able to obtain when working with his 
own Microscope, it being always more difficult to obtain the same effect 
with a strange Microscope than with an instrument to which a person 
was accustomed. He desired to acknowledge the assistance which he 
had received from Mr. Nelson, and also his indebtedness to Dr. Czapski, 
who had already been of very great help to him in bringing out this 
method. 
The President was sure it would be the desire of the Society to pass 
a hearty vote of thanks to Mr. Rheinberg for his very admirable and 
extremely interesting paper, the subject of which, with the exception of 
what Mr. Hardy had done, was entirely novel, and had certainly been 
worked out in a most ingenious manner. Mr. Hardy’s invention could, 
he thought, hardly be considered identical, seeing that it did not pretend 
to be a scientific but only an ornamental device. He had for a long 
time been of opinion that the differentiation by contrast of colours was a 
process of considerable value, and he had himself, in a totally different 
manner, endeavoured to get similar effects by the employment of oblique 
polarised light with a selenite film and a black ground. By throwing 
this upon an object mounted in glycerin — such as one of the delicate 
Crustacea — the body of which would depolarise light, but the extremely 
fine hairs of which would not, these hairs would pick up the coloured 
light from the selenite, and in this way he was able to get a differentia- 
tion by brilliant colour which he was otherwise unable to obtain. This 
plan was, of course, only available for low^power objects. The process 
described by Mr. Rheinberg would, in a much simpler and more perfect 
manner, do all that he had aimed at, and he had great hopes of seeing it 
turn out to be of practical value. He also desired to express at the 
same time their thanks to Dr. Czapski for his presence and his remarks 
that evening. 
The thanks of the meeting were unanimously voted, and the proceed- 
ings adjourned to June 17th, which the President intimated would be 
the last meeting of the present session. 
