SCIENCE. 



[Vol. XIV. No. 3 



Sprague £lectric Railway and Motor Company 



Lightest Weight Consistent with 

 Highest Efficiency, 



SliVIPLE IN CONSTRUCTION. 

 Not Liable to get out of Order. 



Bearings Self Oiling. 

 NON-SPARKING IN OPERATION. 



Commutator Wear Reduced 

 to a Minimum. 



16 and 18 BROAD STREET, NEW YORK. 



SILKS. 



JAMES MCGREERY& CO. 



are showing for the holidays and the Ball sea- 

 son the very latest ideas of Fashion in Rich Silk 

 Novelties, 



They also show large assortments of styles 

 equally handsome and effective, but not quite so 

 novel, at greatly reduced prices. 



Plain Silks have been specially made to com- 

 bine with the above, thus avoiding the annoyance 

 frequently experienced in making combinations, 



JAMES McCREERY & CO. 



BROADWAY AND ELEVENTH STREET, 



NEW YORK, 



s-,.^ 

 ^-'■b,., 





Jiie 



-".''f 



E & H. T ANTHONY & CO. 

 5QI Broadway, N.Y. 



M.inufacturers and Impoiters ot 

 ^ PHOTOGRAPHIC INSTRUMENTS, 

 g.A.pparatus and. Supplies of every 

 riptlbn. Sole proprietors of 

 Patent Detective, Fairy Nov- 

 ind Bicycle Cameras, and the 

 & Celebrated Stanley Dry Plates. 

 Amateur Outfits in great variety, from $9.00 u pwa rd. 

 Send for Catalogue or call and examine. {^"More 

 than 40 years established in this line of business. 



(For Chemical Manufacturers,) Sold at 

 MINERALS, -^ For Blowpipe Analysis, > Lowest Prices 



(.For Technical Purposes J By Weight. 

 Most varied and complete stock of fine cabinet speci- 

 mens in U. S. Recent additions include fine Fluorite, 

 Calcite, Barite. Specular Iron, etc., from England ; Ber- 

 trandite. Phenacite, Descloizite, Brochantite, Vanadinite, 

 Copper Pseudomorphs after Azurite, etc., from U. S. 

 Send for complete catalogue free. 



GEO. L. ENGLISH & CO., Dealers in Minerals, 

 1512 Chestnut St., Philadelphia, Pa 



Readers of Science 



Corresponding with or visiting Advertisers, 

 will confer a great favor by mentioning this paper. 



H. Wunclerlicli & Co., 



868 BROADWAY, 



NEW YORK, 



Invite special attention to their latest 

 importations of Modern Etchings, En- 

 gravings, Brown's Carbon Photographs 

 and Watercolor Paintings, also to their 

 large collection of Rare English Mezzo- 

 tints, Fancy Subjects by Bartolozzi, 

 old Line Engravings, and Original 

 Works by Rembrandt, Durer, and other 

 old masters. 



IMPROVED OIL LIGHT 



MAGIC LANTERNS. 



Also Lime and Electric Light Apparatus, and 



mechanical, plain, and fine colored views. 



J. B. COLT & CO., Manufacturers, 



No. 16 BhEKMAN Street, New York. 



WALKER PRIZES IN NATURAL HISTORY. 



The Boston Society of Natural History- offers a first 

 prize of from S60 to Sroo, and a second prize cf S50, for 

 the best memoir, in English, on one of the following sub- 

 jects : I. On the Adaptive Resemblances of Plants in 

 Different Natural Orders. 2. On the Processes Involved 

 in the Production of Soils. Memoirs must be handed to 

 the Secretary before April 15th, i8go. Prizes will not be 

 awarded unless the papers are deemed of adequate merit. 

 For further particulars apply to 



J. WALTER FEWKES, Secretary. 



Boston, Mass., Dec. 18th, 1889. 



One Tliousand Dollar Prize ! 



THE AMERICAN SECULAR UNION offer a prize 

 of ONE THOUS.^ND DOLLARS for the best essay, 

 treatise, or manual, to aid teachers In our Public 

 Schools in instructing cliUdren in the purest prin- 

 ciples of morality without Inculcating religious doc- 

 trines. For particulars apply to E. B. WESTBROOK, 



Philadelphia, Nov. 1889. 1707 Oxford St. 



FOOD 

 ADULTERATION 



And its Deteci 



With photomicrographic plates and 

 ix. By J. P. Battershall. 328 

 83-50. Circulars and Catalogues 

 & F. N, SPON, 



iVdandt St., New York. 



THE 



Bell Te 



COMPANY. 



98 MILK ST., BOSTON, MASS, 



This Company owns the Letters 

 Patent granted to Alexander Gra 

 ham Bell, March 7th, 1876, No 

 174,465, and January 30, 187 7 

 No. 186,787. 



The Transmission of Speech b 

 all known forms of ELEGTRK 

 SPEAKING TELEPHONES in 

 fringes the right secured to thi 

 Company by the above patents, au< 

 renders each individual user of tel- 

 ephones, not furnished by it or its 

 licensees, responsible for such un- 

 lawful use, and all the conse 

 queuees thereof and liable to suit 

 therefor. 



ESTERBROOK'S 

 STEEL PENS 



OP SUPERIOR AND STANDARD QUALITY. 

 Leading Nos.: 048, 14, 130, 135, 239, 333 



jFoi' Sale by all Stationers. 



THE ESTERBROOK STEEL PEN CO., 



Works ; Oamden, N. J. -JG John .'■it.. Sew Vol' 



■C. 



.,, iNTHE WORLD. ( 



^aOLDMEtt\L, 



li2Mi>^_ 



Used by thousands o£ first-clas3 

 mechanics and bv such manufact- 

 urera as Pullman" Palace Car Co., 

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Repairs Everything. 



Its success hag brought, a lot of 

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 OsLY GENUINE LePaee'aL'qu; 

 Glue is manufactured solely jv t\ 



RUSSIA CEMENT C 



GLOUCESTER, MAS3. 

 Send 10c. and dealers' card wh.', 

 >e3n't keep it in atook, forsamplfl, 



