*, i nee 
Ps AT 
14 THE Microscope. 
BULLOCH’S COMBINATION MICROTOME. 
ee the description and illustration were published, the 
microtome has been further improved. The attachment or 
clamp for holding the knife, consists of two disks; and when — 
placed in position at zero, which is indicated by a spring stop, 
are four-tenths inch thick; each disk is two inches in diameter, 
and made in the form of a wedge of about six degrees. The 
lower disk is divided into 25 parts, and by the proper pusition 
of each wedge, any inclination or adjustment can be given to 
the knife. The periphery of the elevating wheel has been cut 
with ratchet, the same as others with feeding attachment; but 
the adjustment for graduating the amount of elevation is on the 
block which carries the knife, and is adjusted by means of a 
sliding arm-piece ; and can be gauged from one to twenty teeth, 
or 1-200 to110 mm. By this method the knife carrier can be 
used on the full length of the bed at any adjustment of the feed- 
ing attachment. A ribbon carrier has also been attached. 
<4 o> 
EDITORIAL NOTES. 
Pror. Smirn’s New Worx.—We have recently been enjoy- 
ing the great pleasure of examining the plates of Prof. H. L. 
Smith’s work on “* Contributions towards the lite history of the 
Diatomacee.” This work has just been completed after 
years of most earnest labor. The package before us con- 
tains forty-eight colored plates on heavy board, 14 x 18 inches. 
Each plate is most beautifully finished in water colors of vari- 
ous hues, representing some important point in the life history 
of these interesting forms. To examine the plates alone for 
their artistic finish would be both pleasant and profitable to any 
one who loves that which is beautiful in art. When we add to 
this the fact that each plate represents to us some important 
fact in natural science, presented by the very highest authority 
in the world on this particular subject, and presented, too, for 
the first time, we are ready to assert that no more valuable con- 
tribution has been made to science during the present genera- 
tion. It is the first complete work on this subject ever offered 
