1885.] Scientific News. $ 1025 
varied from a minimum, depending on the perfection with which 
the razor is sharpened, to a maximum of 3% of zg of z or ory 
ofa turn. The practical minimum thickness obtainable with a good 
razor is approximately 4y}voy of an inch. The value of the teeth 
on the milled wheel are as follows : 
I tooth of the milled wheel = ṣy4yy of an inch = .000625™m 
Ztek- 4 " “ = yko “ ‘* = ,oor250"= 
4 6 e « é = Totoo ` “ c = 0025™™ 
16 “se (13 (3 4 = 1 se “6 z oymm 
2500 
The movement of the lever which carries the embedded object 
is effected by a string attached to the end of the lever. This 
string passes under a pulley and is fastened to the arm carryin 
the pawl. Attached to the other end of the lever is a spring pull- 
ing downwards. ~- 
en the arm is moved forwards the feed takes place, the 
string is pulled, the embedded object is raised past the razor, and 
the string is stretched. When the arm is allowed to move back 
the spring draws the imbedded object across the edge of the 
razor, and the section is cut. The string is attached to the lever 
by a screw which allows the position of the embedded object to 
be adjusted so that, at the end of the forward stroke, it is only 
Just past the edge of the razor. This is an important adjustment, 
as it causes the razor to commence the cut when the object is 
traveling slowly, and produces the most favorable conditions for 
the sections to adhere to each other. 
:0: 
SCIENTIFIC NEWS. 
— To the report of the Commissioner of Fisheries of New 
York in charge of the oyster investigation is appended Dr. H. J. 
Rice’s excellent tract on the propagation and natural history of 
e American oyster. An account is first given of experiments 
carried on at Cold Spring harbor on the propagation of the oys- 
ter, and then follows notes on the distribution of the animal, the 
Structure of its shell, the gross anatomy of the animal including 
the reproductive organs, succeeded by chapters on seed oysters, 
the food of the oyster, its coloration, its artificial propagation, 
€ methods of obtaining spat, and the friends and enemies of the 
Oyster. Reference is made to the supposed method of extraction 
