25° 



SCIENCE. 



[Vol. XIX. No 482 



soon as the current reached the ground, the wet earth being a 

 good conductor? 



3. Why did not the lightning strike the trees on the summit 

 rather than one several feet below, and why not the top of the 

 latter? 



3. Why did it indent the pipes, and why the edges facing the 

 current rather than the other ? Is electricity material ? Can any- 

 thing not material manifest such a vis viva or working energy ? 

 Why was the iron melted when electricity has no inherent beat? 



4. Do not the effects at the junctions of the pipes indicate a sort 

 of damming up of the current by the cement until the pressure 

 became sufficient to burst the barrier, and then it struck the fol- 

 lowing edge with its accumulated flood? 



Marshall Henshaw. 



Amherst, Mass., Apr. 21. 



[The phenomena presented in lightning strokes have hereto- 

 fore appeared so lawless that it may be well to call attention to 

 the fact, which has been repeatedly observed, that but little dam- 

 age is generally done to portions of trees on the same levels as the 

 foliage. It has also been observed that the presence on any level 

 of a conductor of considerable surface, and consequent large 

 electrical capacity, mitigates the effects on that level. Whether 

 the large conducting surface presented by the wet leaves of a 

 tree is a parallel case is, of course, a question ; but the fact as 



stated is among those well authenticated in regard to lightning 

 effects.— Ed.] 



Periodicity of the Aurora. 



On Saturday night, April 23, there was a fine Aurora seen in 

 this locality whenever the clouds broke away until after midnight. 

 This display is specially interesting because it is the sixth consecu- 

 tive return of an aurora at the precise interval of twenty-seven 

 days, the dates being as follows : Dec. 9, Jan. 5, Feb. 3, Feb. 29, 

 March 27, and April 33. The display will be due again upon May 

 30. It has been associated with reappearances at the sun's eastern 

 limb of an area south of the equator which has been much fre- 

 quented by spots and faculse. In like manner a record now be- 

 fore me shows that reappearances at the eastern limb of disturbed 

 areas in the sun's northern hemisphere have their chief magnetic 

 effect during the autumn months. From this it would seem that 

 in order that a solar disturbance may affect the earth's magnetism 

 it must be in a particular location, namely, at the eastern limb 

 and as near as possible to the plane of the earth's orbit. Certainly 

 such disturbances do not have their magnetic effect promiscuously 

 in all locations, or at present we should have auroras and magnetic 

 storms continuously, which is very far from being the case. 



M. A. Veeder. 

 Lyons, N.Y., AprU 25. 



CALENDAR OF SOCIETIES. 



Philosophical Society, Washington. 



April 23.— G. M. Searle, On a Simple 



Form of Double-Image Micrometer; Arthur 



Keith, The Geology of Chilhowee Mountain 



in Tennessee ; B. E. Fernow, Timber Physics. 



Chemical Society, Washington. 



April 14. — Wm. H. Krug, On Behavior 

 of Acetone and Carbo-Hydrates ; F. W. 

 Clarke, On the Decomposition of Certain 

 Silicates by Heat; Thomas Taylor, Smoke- 

 less Powder. 



Publications Received at Editor's Office. 



Bryant, William C. Sella, Thanatopsis and other 



Poems. Boston, Houghton, Mifflin & Co. 16°, 



paper. 95 p. 15 ots. 

 Gore, J Howard. A German Science Reader. 



Boston, D. C. Heath & Co. 12°. 196 p. 80 cts. 

 Miller, Olive Thorne. Little Brothers of the Air. 



Boston, Houghton, Mifflin & Co. 12°. 271 p. 



$1.25. 

 Posse, Nils. Handbook of School Gymnastics of the 



Swedish System. Boston, Lee & Shepard. 18". 



192 p. 50 cts. 

 Weed, Clarence M. Spraying Crops. New York, 



Rural Pub. Co. 16°. 110 p. 111. 



A TEMPORARY BINDER 



for Science is now ready, and will be mailed 



postpaid on receipt of 75 cents. 



This binder is strong, durable and 

 elegant, has gilt side-title, and al- 

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 fectly flat. Any number can be 

 taken out or replaced without dis- 

 turbing the others, and the papers 

 are not mutilated for subsequent 

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 binder, Sczenceis always convenient 

 for reference. 



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874 Broadway, New York. 



An Illustrated Journal for Mothers. 



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Exchanges. 



[Free of charge to all, if of satisfactory character. 

 Address N. D. C. Hodges, 874 Broadway, New York.] 



For sale or exchange. Das Ausland, 10 vols., 1882 to 

 1891, including 6 vols, bound, 4 in numbers. Wheeler 

 Survey, vol. i. Geog. Report: also vol. 6, Botany; Pro- 

 duction of eold and silver in the United States, 18S0, 'i, 

 '2, '3, '5; Selfridge Isthmus of Darien. Will sell at very 

 low prices. J. t . James, 1443 Corcoran St., Washing- 

 ton, D. C. 



For exchange.— A fine thirteen-keyed flute in leather 

 covered case, for a photograph camera suitable for mak- 

 ing lantern slides. Flute cost $27, and is nearly new. 

 U. O. COX, Mankato, Minn. 



T© exchange ; Experiment Station bulletins and 

 reports for bulletins and reports not in my file. I 

 will send list of what I have for exchange. P. E. 

 ROLFS, Lake City, Florida. 



Finished specimens of all colors of Vermont marble for 

 fine fossils or cr>'stals. Will be given only for valuable 

 specimens because of the cost of polishing. GEO. W. 

 PERRY, State Geologist, Rutland, Vt. 



For exchange.— Three copies of " American State 

 Papers Bearing on Sunday Legislation," i8gr, S2.5O1 new 

 and unused, for "'The Sabbath," by Harmon Kingsbury, 

 1840; ''The Sabbath," by A. A. Phelps, 1842; " History 

 of the Institution of the Sabbath Day, Its Uses and 

 Abuses," by VV. L. Fisher, iT 

 the Law," by Irving Browne 

 to value of books exchanged, 

 mental legislation in reference 

 etc. If preferred, I will sell 



d buy other book' 



DISON BLAKELY, Chicago, ill. 



.r other wo _ 

 the question of govern- 

 religion, personal liberty, 

 American State Papers," 

 ubject. WILLIAM AD- 



Wanted, in exchange for the following works, any 

 standard works on Surgery and on Diseases of Children: 

 Wilson's "American Ornithology," 3 vols.: Coues' ''Birds 

 of the Northwest " and '' Birds of the Colorado Valley," 

 2 vols.; Minot's " Land and Game Birds of New Eng- 

 land;" Samuels' '■■ Our Northern and Eastern Birds;" all 

 the Reports on the Birds of the Pacific R. R. Survey, 

 bound in 2 vols., morocco; and a complete set of the 

 Reports of the Arkansas Geological Survey. Please give 

 editions and dates in corresponding. R. ELLSWORTH 

 CALL, High School, Des Moines. Iowa. 



To exchange Wright's " Ice Age in North America " 

 and Le Conte's ''Elements of Geology" (Copyright 1882) 

 for "Darwinism," by A. R.Wallace. "Origin of Species," 

 by Darwin. "Descent of Man," by Darwin, ''Man's 

 Place in Nature," Huxley, *'Mental Evolution in Ani- 

 mals," by Romanes, ''Pre-Adamites." by Winchell. No 

 books wanted except latest editions, and books in good 

 condition. C. S. Brown, Jr., Vanderbilt University, 

 Nashville, Tenn. 



For Sale or Exchange for books a complete private 

 chemical laboratory outfit. Includes large Becker bal- 

 ance (2oog. to i-iomg.), platinum dishes and crucibles, 

 agate motors, glass-blowing apparatus, etc. For sale in 

 part or whole. Also complete file of Sillinian'' s yournal, 

 1862-1885 (62-71 bound); Smithsonian Reports, 1854-1883; 

 U. S. Coast Survey. 1854-1869. Full particulars to en- 

 quirers. F. GARDINER, JR., Pomfret, Conn. 



Wants, 



Any person seeking a position yor ivhic/t he is quali- 

 fied by his scienti/ic attainments^ or any person seeking 

 some one to Jill a position 0/ this character y be it that 

 0/ a teacher 0/ science^ chemist^ draughtsman, or what 

 not, can have the * Want^ inserted under this head 

 at 10 cents a count line. Nothing inserted at less than 

 50 ceuts a time prepaid by stamps^ if inost con-venient, 



TRANSLATOR wanted to read German architec- 

 tural works at sight Cno writing). One familiar 

 with technical terms desired. Address ''A.,*" Bos 

 149, New York Post Offlae, 



WANTED.— A position in a manufacturing estab- 

 lishment by a manufacturing Chemist of in- 

 ventive ability. Address M. W. B , care of Science, 

 874 Broadway, N. Y. 



WANTED.— Books on Anatomy and Hypnotism. 

 Will pay cash or give similar books in es- 

 ige. Also want medical battery and photo out- 

 DR. ANDERSON, 182 State street, Chicago, 111. 



WANTED. — A college graduate with some normal 

 training, to teach the sciences, at $1,800 per 

 year, in a Southern college. A Baptist or a Method- 

 ist preferred. Must also be a first-class Latin 

 scholar. A. H. Beals, Box K, MilledgeTille, Ga. 



A PROFESSORSHIP in Chemistry is wanted by 

 one who has had five years' experience in that 

 capacity. Would prefer to give instruction by 

 lectures and experiments rather than by text-book 

 methods. Would like a position in a college or uni- 

 versity where there is a good student's laboratory. 

 Special points of strength claimed are: O) Thorough 

 control of a class and good order during lectures 

 and recitations. C2) Accuracy in experimenting 

 with chemicals and skill in the manipulation of 

 chemical apparatus. The permission of several dis- 

 tinguished educators has been given to refer to 

 them if required. Would not care to accept a po- 

 sition paying less than ©1,500. Address B. E , care 

 of Science, Advertising Dept., 47 Lafayette Place, 

 New York, 



\ DDRESS WANTED.— Will some one please send 

 rV the address of the Secretary of the American 



Philological Society. Also that of Herbert Spencer. 



"ADDISON," Room 84, 164 Madison St., Chicago, 111. 



ADDRESSES of Old Book Dealers wanted.— Wish- 

 ing to obtain a number of old books out of print. 

 I very much desire the addresses or catalogues of 

 rare second-hand book dealers. If„there is a direc- 

 tory or list of such dealers I should like to obtain 

 possession of one. W. A. BLAKELY. Chicago, 111. 



WANTED.— (1) A white man versed in wood and 

 iron working, able to work from specifications 

 and plans, suited for an instructor of boys; bis bus- 

 iness to have charge of shops of school, outline and 

 direct the work for foremen and students: salary to 

 be $1,000 per annum (nine months). (2) A man 

 (black preferred) to teach the colored, iron working 

 and forging, subordinate to the preceding; salary, 

 S720. (3) A man (white) competent to take classes 

 in engineering (assistant's position), but with the 

 ability to perform any of the work required in any 

 of the ordinary engineering courses of our universi- 

 ties; salary from $1,000 to $1,500. A. H. BEALS, 

 MiUedgeville, Ga. 



