504 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Fig. 53 shows my rotating nosepiece, consisting of a screw fitting 
to the objective end, and a divided circle fitting to the objectives and 
rotating. An index pointer sprung 
on to the nozzle shows the angle 
of rotation ; the other end of the 
rotating tube is adapted to receive 
the analysing prism or a double- 
image prism, which can be used for 
measuring the angles of crystals by 
rotating the magnified extraordinary 
image round the ordinary. It can 
also be used in testing objectives.” 
Dumaige’s “New Model of Micro- 
scope.” * — M. Fabre Domergue de- 
scribes and figures what he calls 
“ un nouveau modele do Microscope/' 
constructed by M. Dumaige of Paris. 
We cannot, however, discover any- 
thing new in the instrument, and the 
only points to remark on are : — (1) 
the teeth of the rack are of ovoid 
section, and are set obliquely (a plan 
we believe not previously adopted 
in a French Microscope) ; (2) the 
carrier for the Abbe condenser is of 
reduced size, so as not to require 
the stage to be raised too much above 
the base ; and (3) the pivot on which 
the condenser carrier turns is fixed to a slight prolongation from the 
right posterior corner of the stage, which the author considers to be 
“a very great advantage; it constitutes for the hand that works the 
micrometer-screw a kind of natural support, and allows the fingers 
much ease and suppleness in using the screw.” 
M. Fabre Domergue refers to condensers as having been “ completely 
neglected ten years ago ! ” The introduction of the Abbe condenser, he 
says, imposes upon constructors the necessity of modifying the old models 
of stands so as to allow of the introduction of condensers beneath the 
stage. 
Hart’s Microtome-Microscope, j — The following is the abstract of a 
paper by Dr. C. P. Hart, as printed in the Proceedings of the American 
Association for the Advancement of Science, under the title of “ A new, 
cheap, useful, and quickly constructed adjustable Microtome .” 
“ This instrument is nothing more nor less than a Bausch and Lomb 
“ Microscope-stand, converted into a microtome by the following changes : 
“ — Having removed the substage, the slide-carrier clips, the objective 
“ adapter, and the draw-tubes, a suitable razor-blade is permanently fixed 
“ to the slide-carrier, so as to have a corresponding universal lever move- 
* Ann. de Micrographie, ii. (1890) pp. 164-7 (1 fig.), 
f Proc. Amer. Assoc. Adv. Sci. for 1885(1886) p. 356. 
Fig. 53. 
