676 
PECCEEDINGS OF THE SOCIETY. 
well as the body-tubes, might always be made of this alloy with advan- 
tage, especially when their weight w r as carried by the threads of a micro- 
meter screw fine adjustment without the interposition of some sort of a 
lever. 
He next exhibited a Dissecting Stand by Andrew Ross, and said that 
this stand was modelled on two older forms, of which the first was Ellis’s 
Aquatic Microscope, made by J. Cuff (1755), and the other was Valentin’s 
Microscope, made by Andrew Ross (1S31). The instrument was about 
forty-five or fifty years old, and was still a thoroughly good working 
instrument. The lenses were all non-achromatic, but nevertheless gave 
very good images. 
Mr, C. Lees Curties, being asked by the President to describe some 
photomicrographs in natural colours exhibited in the Kromskop, said 
that Mr. E. R. Turner, w r ho had made the apparatus and photographs, was 
in the room and would no doubt say a few words about them. 
Mr. Turner said he had not come with any intention of speaking, 
but would make a few remarks which might be of interest, Mr. Ives’ 
process of colour photography was fairly well known to most persons 
who took an interest in such things ; it consisted in taking three nega- 
tives through colour screens, each of which consisted of a colour record 
of the original subject. If positives from these negatives were put into 
the Kromskop, an instrument which would optically re-combine the three 
images, each illuminated with its own colour, the result was a single 
picture in the natural colours. It was an optical illusion and not a 
concrete photograph in colours, and the only new thing about those 
exhibited in the room was in applying the process to photomicrography 
and taking the pictures stereoscopically. In doing this, ordinary objec- 
tives were used in conjunction with a pair of reversing prisms, and the 
object was photographed through red, green, and blue-violet screens. 
These, when properly mounted, and when put into the Kromskop, re- 
combined the three colours of which the negatives were records, and 
represented the object in the colours which it originally expressed. 
The thanks of the Society were, upon the motion of the President, 
cordially voted to Mr. Turner for describing this process, and for bring- 
ing the photographs and the apparatus for them to see. 
Dr. Hebb said another paper had been received from Mr. Millett, 
being Part VI. of his communications on the Foraminifera k of the Malay 
Archipelago. It consisted largely of descriptions and lists of species, 
and being too technical to read to the Meeting, would be taken as read, 
but would be printed in extenso in the Journal. 
The thanks of the Society were unanimously voted to Mr. Millett 
for his paper. 
Mr. F« Enock gave an extremely interesting account of his observa- 
tions on the life-history and habits of British Trap-door Spiders, illus- 
trating the subject by a large number of original lantern views. 
Mr. Vezey said, as he was somewhat responsible for Mr. Enock’s 
appearance there that evenin'.’, lie should like to express the obligation 
