ONE DOLLAR 
EACH IS OFFERED for one copy of THE 
AMERICAN NATURALIST for December, 1888, 
and for December, 189r. 
LOCKBOX 2, WILLIAMSTOWN, MASS. 
MARINE BIOLOGICAL SUPPLY DEPARTMENT 
Preserved material of all P of animals, for class 
work or for the museum. For price list 
xd all uerus address 
GEO. . GEO. M. GRAY, CURATOR - - WOODS HOLL, Mass. 
DISS e NG MICROSCOPES 
of = Size, style and price, suited 
or all kinds of work. ' 
A new series of lenses 
for dissecting work have 
recently been perfected by 
us which have unusually 
long working distance and 
large flat field. These 
Lens «tolder for Anatomical Work. lenses are offered at 
prices less than any lenses of equal quality heretofore ; 
in use. The new Dissecting Stands are all nickeled 
metal with glass stage. J~ Catalog free. 
Sample copy JOURNAL OF APPLIED MICROSCOPY on request. 
BAUSCH & LOMB OPTICAL CO. 
NEW YORK OFFICE: aee x 
25th Street an. and Broadway, OCHESTER s Y. Btate and Washington Btreeta, 
Townsend Bldg. Ri N.Y Stewart Bldg. - 
THE ONLY MACHINE _ 
The only machine ever — which will add — 
TA o 
of nothing more, 
The only F ever Iit which multiplies 
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Absolute accuracy and jue as quick as the best d 7 
accountant. No lever to operate. Nothing to to do = 
m z E e cn oe Pee 
moo uM um CHICAGO, V.S.A. * 
