CONSERVATION'S ADVERTISERS 



GOERZ LENSES 



are made by skilled workmen according to 

 latest scientific methods Every lens is as near 

 perfection as a photographic lens can be. The 

 Stigmatisni is completely corrected, and at 

 full opening every lens will cover sharply to the 

 very edges the size of plate for which it is in- 

 tended. 



No other lens has -such a world-wide reputa- 

 tion ; but it is not for its reputation that you 

 buy a "GOERZ"— it is for the satisfaction of 

 having a lens that knows ro limitations, that 

 will do all the work of other lenses better and 

 then do work that could not be done at all 

 with them. This is why you should equip 

 your camera or kodak with a Goerz Lens. 



WRITE DEPT. ? FOR OUR LENS CATALOGUE. 

 WHKH ALSO DESCRIBES OUR FULL LINE OF FIELD 

 GLASSES, XL SHUTTER. ANSCHUTZ CAMERA AND 

 OTHER ARTICLES OF OUR MANUFACTURE. 



Our catalogue "de luxe," a most coinplcte book 

 of information on lenses, is sent for nine cents to 

 cover postage. 



Our lenses may be obtained through all good 

 photo dealers or direct. 



01. 5P* ^0^rg Attt^rtratt 

 ®pttral Olompatig 



52 Union Square, E., New York 

 Heyworth Bldg., Chicago 



Second Edition, Revised, with Additions 



Snow — The Principal Species 



of Wood. Their Characteristic 



Properties 



By Charles H. Snow 



Dean of the School of Applied 

 Science, Nczv York University 



Large 8vo, xi+203 pages, figures in 

 the text, 37 full-page half-tones. 

 Cloth, $3.50 



Circular giving complete tabic of contents 

 and sample pages mailed on request, or 

 the book may be seen at the leading book 

 stores or dealers in architectural supplies 



Order through your bookseller, or copies -will he for- 

 warded postpaid by the publishers on receipt of the 

 retail prict. 



JOHN WILEY & SONS 



43 and 45 East 19th St., New York City 



This Solar can be used in hazy weather, 

 when other Solars are useless. Used by 

 the U. S. General Land Office. 



Specifications 



Needle 3% Inches 

 long. Graduations 4% 

 Inches long, reading 

 minutes. Power of 

 telescope 20 (with 

 splendid definition, good 

 light, and large field). 

 Variation plate. Level 

 to telescope, clamp 

 and opposing screws. 

 Vertical arc. Fixed 

 Stadiahairs. Extension 

 Tripod. Solar At- 

 tachment on side of 

 standards. 



Price Complete, $300 



Telegraph and Code Word. Mountsolar 



Illustrated Catalogue Upon Application 



YOUNG S SONS Phfladelphia 



2b 



In writing to advertisers kindly mention Conservation 



