SCIENCE— ADVERTISEMENTS 



Spencer Microscopes 

 Nos. 44 and 64 



Embody a side-fine adjustment (the critical mechan- 

 ical part of any microscope) of superior type : 



Simplest — fewer parts — ^less to get out of order 



34 threads of the screw engaged as compared 

 with the equivalent of but one in the others. 



I. 

 II. 



III. 



It has a "lateral travel" — an index to its posi- 

 tion, relative to its limits. 



IV. It is fool-proof durable. It cannot be forced 

 beyond its Imiits — steel stops prevent. 



These advantages are the result of our many years of 

 pioneering in side-fine adjustment construction. 



Catalog sent on application 



SPENCER LENS COMPANY 



BUFFALO, N. Y. 



Marine Biological Laboratory 



Woods Hole, Mass. 



INVESTIGATION 



Entlr* Year 



INSTRUCTION 



July 3 to August 13 

 191S 



SUPPLY 

 DEPARTMENT 



Opra tlu Entin Yaw 



Facnlities for research in Zoolosy* 

 Embryology, Physiology and Bot- 

 any. Seventy-six private labora- 

 tories, $100 each for not over three 

 months. Thirty tables are avail- 

 able for beginners in research who 

 desire to work nnder the direction 

 of members of the staff. The fee 

 for such a table is $50.00 



Courses of laboratory instruotion 

 with lectures are offered in Inverte- 

 brate Zoology, Embryology, Physi- 

 ology and Morphology and Taxo- 

 nomy of the Algae. Each course 

 requires the full time of the student. 

 Fee, S50. A lecture course on the 

 Philosophical Aspects of Biology 

 and Allied Sciences is also offered. 



Animals and plants, preserved, Uv- 

 Ing, and in embryonic stares. 

 Preserved material of all ^rpes of 

 animftTfl and of Aigae, Fungi, Liver- 

 wortfl and Mosses furnished for 

 elanwork, or for the museum. 

 Living material furnished in season 

 ■s ordered. Price lists of Zoological 

 ■md Botanical material sent on ap- 

 ^ieation. State which is desireo. 

 rat pries lists and all informstioB 

 iecv£nc material, addrssi 



OKO. M. GRAY, Cmstor, Wood* Hole, Mas. 



Tha aBBaal announeemsBt will bo sea (on sppUcatioB to Hi* 

 DtraetoT, Maria* Blologioal Laboratorr, Woods Hoi*. Mas*. 



Cooking Class at the 

 South Dakota State College 



are using gas made by 



The "Detroit" 

 Combination Gas Machine 



for supplying gas in Departments of 



Domestic Science 

 Chemistry and Physics 



(Over 30,000 in daily aie) 



Laboratory work can be done better, 

 quicker and cheaper by using this gas. 

 Ask for descriptive catalog and names 

 of users in your vicinity. 



Detroit Heating & Lighting Co. 



612 Wight St. Detroit, Mich. 



Eit. 1868 



