l^OI^Oh* 



S C I E NCE 



[Entered at the PosT-Offloe of New York, N.Y., as Secoud-Class Matter.] 



Ninth Year. 

 Vol. XVIII. No. 446. 



NEW YORK, August 31, 1891. 



Single Copies, Ten Cents. 

 $3.50 Per Year, in Advance. 



Just Issited 



Plane and Solid Geometry 



By SETH T. STEWART, A.B. (Yale) 

 i2mo, Cloth. Price, $i.i2. 



Among the many new features that characterize this book are : 



1. A more systematic arranijement of the subject-matter. There is an orderly develop- 

 ment of thought, and related propositions are always found in the same group. 



2. Each book and each section is preceded by a synopsis, which presents at a glanee the 

 subject-matter covered. 



3. An imusual number of original exercises, and these as thoroughly graded as the theo- 

 rems which they emphasize. 



4. A great abundance of practical work, consisting especially of numerical problems and 

 manual practice with the rule and compass. 



5. A careful arrangement of the book, so that in every case the theorem, figure, and 

 demonstration are on the same page or in the same opening of the book. 



6. The use of all approved methods of terminology and statement. 



7. General scholia follow several of the books and sections, presenting important matter 

 not often found in text-books of Geometry. 



8. An unusual variety of demonstrations. 



9. The diagrams are so drawn that each of the various styles of line employed has its 

 own meaning to the student. 



10. The figures in the Solid Geometry are shown in perspective. Thus the pupil is aided 

 by a pictorial effect which, in many theorems, is of great assistance. 



AMERICAN BOOK COMPANY 



NEW YORK CINCINNATI CHICAGO 



Specimen copies will be mailed to any address on receipt of price. Teachers who believe that im- 

 provement in the present methods of teaching Geometry is possible are cordially invited to correspond 

 with us in reference to this new work. 



PROTECTION FROM LIGHTNING. 



All the capital desired for the parent company 

 to handle my patents on a new method of protect- 

 ing buildings from lightning has been subscribed. 

 Sub-companies and agencies to introduce the 

 invention are forming, and any desirous of tak- 

 ing State-rights should address The American 

 Lightning Protection Co., Sioux City, Iowa. 



The English patent is or sale, and offers 

 an excellent opportunity for the formation of a 

 company now that the American company is so 

 favorably started. 



N. D. C. HODGES, 47 Lafayette Place, New York. 



THE 



COMPANY. 



95 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, 1§77, 

 No. 1§6,787. 



The Transmission of Speech by 

 all known forms of ELECTRIC 

 SPEAKING TELEPHONES in- 

 fringes the right secured to this 

 Company by the above patents, and 

 renders each individual user of tel- 

 ephones, not furnished by it or its 

 licensees, responsible for such un- 

 lawful use, and all the conse- 

 quences thereof and liable to suit 

 therefor. 



QUERY. 



Can any reader of Science cite 

 a case of lightning stroke in 

 which the dissipation of a small 

 conductor (one-sixteenth of an 

 inch in diameter, say,) has failed 

 to protect between two horizon- 

 tal planes passing through its 

 upper and lower ends respective- 

 ly? Plenty of cases have been 

 found which show that when the 

 conductor is dissipated the build- 

 ing is not injured to the extent 

 explained (for many of these see 

 volumes of Philosophical Trans- 

 actions at the time when light 

 ning was attracting the attention 

 of the Royal Society), but not 

 an exception is yet known, al- 

 though this query has been pub- 

 lished far and wide among elec- 

 tricians. 



First inserted June 19. No response 

 to date. 



H. D. C. HODGES, 47 Lafayette Place, N. Y. 



