PKOTO -MICROGRAPHY. 



GAYTON A. DOUGLASS & CO. 



Merchants in all supplies pertaining to 

 Photography. 



Catalogues furnished on application. 

 Correspondence solicited. 



185 & 187 Wabash Ave., Chicago. 



'phe Travelers Insurance Company 



of Hartford, Conn., organized 1864, issues both Life Policies 

 and Accident Policies. Only large accident company in America. 

 Only $5 a year to professional and business men for each $1,000 

 insurance, with $5 weekly indemnity. Has paid policy-holders 

 nearly §11,000,000. All policies non-forfeitable. All claims paid, 

 without discount, and immediately on receipt of satisfactory proofs. 



Straight Cut Cigarettes. 



People of refined taste who desire 

 exceptionally fine cigarettes should use 

 only our STRAIGHT CUT, put up 

 in satin packets and boxes of 10s. 20s. 

 50s. and 100s. 

 14 PRIZE MEDALS. 



WM. S. KIMBALL & CO. 



SAMUEL HENSON, 



Mineralogist and Geologist, 



invites visitors to London to inspect his choice speci- 

 mens of Minerals, Gems, and Polished Stones. 



Catalogue on application. 

 SAMUEL HENSON, 277 Strand, London, 



OPPOSITE NORFOLK STREET. 



QUSTAV E. STECHERT, 



766 Broadway, New York. 



Importer of Scientific Books and Periodicals. 



Branches : Leipzig. Hospital Str. 16 ; London, 26 

 King William Str., Strand. 



ft WESTERMANN & CO., 



{Established 1848.) 



838 Broadway . . . NEW YORK, 



FOREIGN BOOKSELLERS AND IMPORTERS. 



SCIENCE. 



AN ILLUSTRATED WEEKLY JOURNAL. THE SCIENCE 

 COMPANY, OWNERS AND PUBLISHERS. 



Officers and Directors.— D. C. Gilman, of Baltimore, President; 

 Sikon Newcomb, of Washington, Vice-President; Gardiner G. Hub- 

 bard, of Washington: Alfx. Graham Bell, of Washington; O. C. 

 Maksh, of New Haven • J. W. Powell, of Washington; W. P.' Trow- 

 bridge, of New York ; S. H. Scudder, of Cambridge. 



SCIENCE appears every Friday. Volumes begin in July and January. 

 Communications will be welcomed from any quarter. Rejected manu- 

 scripts will be returned to the authors only when the requisite amount of 

 postage accompanies the manuscript. 



Address all correspondence to u 3(^J£>tq£ " 



47 Lafayette Place. New York. 



Subscriptions.— In United States and Canada, $5 a year. 



In Great Britain and Europe, $6 a year. 



s 



HORSFORD'S 



Acid Phosphate 



(Liquid), 



For Dyspepsia, Mental and Physical Exhaustion, 

 Nervousness, Wakefulness, Diminished Vitality, 

 etc. 



Prepared according to the directions of Pro- 

 fessor E. N. Horsford of Cambridge, from the 

 phosphates of lime, magnesia, potash, and iron, 

 with phosphoric acid in such form as to be readily 

 assimilated by the system. 



Universally prescribed by physicians. 



It is not nauseous, but agreeable to the taste. 



No danger can attend its use. 



Its action will harmonize with such stimulants as 

 are necessary to take. 



It makes a delicious drink with water and sugar only. 



Prices reasonable. Pamphlet mailed free. 



Rumford Chemical Works, Providence, R. I. 



SUMMER COURSE IN BOTANY. 



At the Botanic Garden of Harvard University, 

 Cambridge. Mass, 



The Course will begin Thursday, July 1, and 

 end Saturday, July 31, 1886. 



Instruction will be given in the Principles of Mor- 

 phology, Outlines of Descriptive Botany, and the Ele- 

 ments of Vegetable Physiology, by Prof. Goodale. 



Mr. F. L. Sargent will give instruction in Methods 

 for identifying Flowering Plants and the more com- 

 mon Cryptogamic Genera. 



The course is designed especially for teachers. Fee 

 for the course $25.00. For further information, address 



Mr. F. L. SARGENT, 417 Broadway, 



CAMBRIDGE, MASS. 



THE CHEAPEST AND BEST ! 



%,6>7 PARK PlflCE, NEW YORK 



Entered at the Post-office in New York as second-class mail matter. Copyright, 1886, by The Science Company. 



