120 MEMORANDA. 
“1. The shape proposed by the Giessen Society is neither 
convenient nor pleasing. 
«2. The object-glasses are somewhat too large to be used 
conveniently on the tables of the small microscopes of Ober- 
hauser, Schiek, &c., most commonly in use (at least in 
Germany). 
«<3. The space for the label is too small. 
«4. They require very small side-glasses, which are difficult 
to be made in the thickness required by many preparations. 
«5, The main objection to this shape is, that it requires 
object-glasses of twofold size, one for marking purposes and 
one for the preparations. Dr. Welker, who first introduced 
and recommended this shape, mentions himself this deficiency 
in his well-known pamphlet, ‘Ueber Aufbewahrung mikro- 
scopischer Praeparate,’ &c., von Dr. Herrmann Welker, 
Giessen, 1856, T. Riekersche Buchhandlung (page 7, note).” 
“The shape, as proposed by us, does not, in our opinion, 
possess any of these inconveniences; it is of the smallest 
size possible for every use, is easily managed, and has suffi- 
cient space for the label. The reasons alleged against the 
use of long-shaped object-glasses (including ours), as men- 
tioned in the paper published by the Giessen Society, are not 
applicable to the shape proposed by us. 
“1, They do not protrude over the margin of the tables in 
any of the microscopes known by us. 
“2. Neither our object-glasses, nor those of the Giessen 
Society, can be turned round upon the small microscopes 
in most common use; in this respect both have indeed the 
same defect. 
“3. The Giessen Society itself agrees that the labels used 
by them are very{small ; at the same time, they say, that they 
can be read while in the boxes. It is exactly the same with 
our collection, as anybody may find in the description given 
in the above-mentioned paper. 
“4, The fourth objection fails of itself, as there are two 
protecting borders in our object-glasses. 
“5. With respect to the space left for the preparation 
itself, ours is more than 100 5 millim larger than the Giessen 
one, and it is a great advantage that it has one longer dia- 
meter, in order to preserve longer preparations. 
“‘ We, therefore, solicit every microscopist taking an interest 
in the mutual imterchange, to decide for one of the above- 
mentioned shapes, after having carefully examined every- 
thing in their favour, or against them ; and we should deem it 
advisable for him to give his opinion, when sending in his 
first preparations. As for the present, we cannot deviate 
