THE MICROSCOPIC AL JOURNAL ADVERTISER- vii 



Large First-Class Microscope For Sale. 



Zentmayer's centennial stand, 3 eyepieces, rotating and reversable mechanical stage. 



Made specially to order 1300.00 



Walnut case with lock, key and handle 10.00 



Bull's eye Condenser 10.00 



J \ and i inch solid eyepieces at 7.50 22.50 



Beck's fii"st class 4-iuch objective, angular aperture 9° 12.00 



" " " 2 " " " " 18° 20.00 



H. R. Spencer &Co's first-class linch objective of 40° 40.00 



" " " " " " " ] " Homogeneous Immersion objective B. A. 110° 65.00 



" " " " " '' " 1-10 inch " " " " " 125° 80.00 



Amplifier 8.00 



Beck's triple nose-piece 15.00 



Webster's Achromatic Condenser 17.50 



Mechanical finger 6.00 



$605.00 

 But little used, and as good as new. Will be sold for $400 to close an estate. 



Address: James H. Logan, 



Perrysyille Ave., Allegheny, Pa. 



AGE PRINTING COMPANY. 



All kinds of scientific matter, books, pamphlets, cards, labels, 

 envelopes, letter heads, etc., printed and forwarded by mail or 

 express free of charge for delivery. Prices reasonable; satisfaction 

 guarantied. 



Inventive Age Building, 



Washington, D. C. 



DESMIDS OF THE UNITED STATES, 



and list of American Pediastrums, with fourteen hundred illustra- 

 tions, on sixty-four colored plates. 



The work consists of 246 printed pages, including a carefully arranged index ; a brief 

 account of Algse in general ; a fuller one of Desmids in particular — directions how to find ' 

 collect, preserve and examine them ; a minute description of each of the 600 species and 

 vareties named in the index, and a descriptive catalogue to every plate of the plants illus- 

 trated thereon. A copy bound in cloth, (carefully packed, and mailed or sent by Express 

 on receipt of the price, $6.50. 



Send all orders and remittances to, 



HARTLEY C. WOLLE, 



Bethlehem, Pennsylvania, U, S. A. 

 |i^°There may be had also. Fresh-water Algae of the United States, $10.00 ; and Diato- 

 macese of North America, price $6.00. 



MODERN MICROSCOPY. 



Part I. — The Microscope and Instructions for its use. 

 Part II. — Microscopic Objects : How prepared and mounted. 

 By Cross and Cole. 



LARGE OCTAVO, 104 PAGES, 30 FIGURES ; PRICE $1.25, POSTPAID. 



Address, Microcsopicaiv Publishing Company, 



"Washington, D .C. 



