11 



SCIENCE.— AD VER TISEMENTS. 



THIN SECTIONS (Microsoopio) 

 OF ROCKS, MINERALS, FOSSILS, ETC., 



carefully mounted, and for sale at selection frona list or In ar- 

 ranged collections, witb descriptive commentaries (prepared by 

 experienced llthologista). Corresponding roclj specimens. 



GRINDING MACHINES 



with latest improvements and fitted to foot power, electric motor, 

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 GUSTAVUS D. JULIEN, 932 Bloomfield St., Hoboken, New Jersey. 



CRELLE, Calculating Tables. 



English Text. Cloth, $5.00. 

 BREMIKER, Logarithmic Tables. 



(C places). Cloth, 81.86. 

 BRUHNS, Logarithmic Tables. 



(7 places). ^ Mor., J2.50. 



VEQA, Logarithmic Tables. 



(7 places). }^ Mor., $2.50. 

 LEMCKE & BUECMNER, 



813 Broadway, New York. 



NEW CATALOGUE. 



We have recently issued a new edition, revised and en- 

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Books on Chemistry, Chemical 

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It is arranged by subjects, and includes all the standard 

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A copy ot this Catalogue will be sent free by mail to any 

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D. Van Nostrand Company, 



Publishers and Importers of Scientific Books, 

 23 Murray St. and 27 Warren St., New York. 



Horsford's Acid Phosphate 



with water and sugar only, makes a de- 

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Dr. M. H. Henry, New York, says: "When 

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Descriptive pamphlet free on application to 

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Beware of Substitutes and Imitations. 



nUAX KOHLi^ Chemnitz^ GS-erxnany^ 



FIRST EUROPEAN MAKER OF 



Physical and Electrical Instruments 



Special Manufacturer of Koentgen X-Kay Outfits. 



Apparatus for Experiments with Currents of Higli Frequence and Tension, 



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Apparatus for Marconi's Wireless Telegraphy, 



Price List No. 10 of Physical Instruments ; nearly 400 pages and more than 1300 engravings (in German, English 

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^PREFERENCES FROM LEADINO EXPERTS. -WS. 



Representative: Messrs. EIMER & AMEND, 205-211 Third Avenue, New York. 



WJVI. GAERTNER & CO., Scientific Instrument Works 



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MINERALS. 



GEO. L. ENGLISH & CO., Mineralogists. 64 E. 13tli St., New York. 



