264 



SCIENCE. 



[Vol. XIX. No 483 



LETTERS TO THE EDITOR. 



#** Correspondents are requested to be as brief as possible. The writer's name 

 is in all cases required as proof of good faith. 



On request in advance^ one hundred copies of the number containing his 

 communication leill be furnished free to any correspondent. 



The editor will be glad to publish any queries consonant with the charactfr 

 of the journal. 



The Color Question 



A FEW weeks ago {Science, March 25) Mr. Milton Bradley wrote 

 to you on this subject, which unfortunately is still in an unsatis- 

 factory state, notwithstanding the researches of Helmholtz and 

 Maxwell. Mr. Bradley is, do doubt, quite right in treating, for 

 the purposes of his system, all the colors of the spectrum as of 

 equal value, but it is by no means as clear as he supposes that the 

 three colors, red, green, and violet, are entitled to be considered 

 primaries in preference to red, yellow, and blue, if any colors are 

 to be thus treated. The fact that Maxwell found the cross-section 

 of a cone of color to be approximately triangular with red, green, 

 and violet at the three corners, proves little as to the real relation 

 between the various colors. It is very easy by means of a prism 

 so to condense a spectrum as that only red, gi'een, and violet shall 

 be visible, and my impression is that some such explanation will 

 be found of Maxwell's supposed elementary green at least. I read 

 with suspicion such statements as that most natural yellows and 

 blues when analyzed by a prism show a large quantity of green 



in their composition, and that yellow can be produced by mingling 

 green and violet. In the former case the green is due probably to 

 an overlapping of the yellow and the blue, notwithstanding the 

 belief, which is erroneous, that the yellow and blue of the prism 

 will not produce green. Anyone on looking through a prism at 

 different objects can easily devise a mode of causing two spectra 

 to overlap, and thus convince himself that the blue and yellow do 

 actually thereby give rise to green. He can, moreover, make the 

 red and violet rays overlap, and thus form shades of purple. Such 

 being the case, green, although sometimes in overlapping spectra 

 observed by looking through the prism it appears to obliterate the 

 blue, is no more entitled to be called a primary color than purple 

 itself. For all practical purposes all the colors should be regarded 

 as primary, the question of their actual relation being left to be set- 

 tled by further investigation. C. Stanilajjd Wake. ' 

 349 North Clark Street, Chicago, 111. 



Family Types. 



Can I ask one or two questions about Mr. Williams's note in the 

 issue of April 15 ? Does the mother in placental mammals tend 

 to assimilate in respect to blood to the father ? Does the result of 

 a study for twenty- five years of one family offer more than the 

 slightest evidence on the point in question? Does the mother 

 frequently acquh-e diseases belonging to the father indirectly 

 through the child she is carrying? Does each child in a family 



CALENDAR OF SOCIETIES.] 



Women's Anthropological Society of 



America, Washington. 



April 30.— Miss Annie T. Smith, Report 

 of the Committee on the Investigation of 

 Directive Forces in Society ; Mrs. York, Med i- 

 cal Inspection of Schools ; Miss Sickles, The 

 Ghost Dance. 



Biological Society, Washington. 

 April 30. — The principal paper of the 

 evening was: The Distribution of Land, 

 Water, and Ice on this Continent in Later 

 Geological Periods, by Professor W. J. Mc- 

 Gee; Communications: Erwin F. Smith, 

 The Relation of Plants to the Soil ; Charles 

 Hallock, Where Salt-Water Fishes Hide: 

 Results of Deep-Water Seining. 



Society of Natural History, Boston. 



May 4. — J. S. Kingsley, Notes on the An- 

 atomy of Amphiuma. 



Publications Received at Editor's Office. 



Batjsch, Edward. Manipulation of the Microscope. 



Rochester, Bausch and Lomb Optical Co. 16''. 



las p. 111. 

 Cathcart George R. Literary Reader; A Manual 



of English Literature. New York, American 



Book Co. ia°. 560 p. $1.15. 

 Chapman, C. H. An Elementary Course in Theory 



of Equations. New York, John Wiley & Sons. 



12°. 98 p. 11.60. 

 Church, Irving P. Notes and Examples in Me- 

 chanics. New ITork, John Wiley & Sons. 8°. 



144 p., plates. $2. 

 Gorman, S. The Discoboli. Cambridge, Museum 



Comp. Zool. 4°, paper. 96 p., plates. 

 Greely, a. W. Irrigation and Water Storage in 



the Arid Regions. Report to the Sec. of War. 



Washington, Government. 4°, paper. 356 p. 



Maps. 

 Hurst, G. H. Silk Dyeing, Printing and Finishing. 



With numerous colored patterns. New York, 



Macmillan & Co. 16°. 184 p. $2. 

 Landauer, J. Blowpipe Analysis. Trans, by James 



Taylor. 2d ed. New York, Macmillan & Co. 



16°. 190 p. 11.10. 

 MoERis, R. Anna. Physical Education in the Pub- 

 lic Schools. New York, American Book Co. 8°. 



192 p. gl. 



Bttsiness Department. 



The Providence and Stonington Steamship 

 Company's new steel steamer New Hamp- 

 shire made a record for phenomenal speed 

 on her trial trip at Wilmington, Del., on 

 April 21, 1892. Loaded with 600 tons dead 

 weight, she made time over the measured 

 mile, two minutes fifty-nine seconds, an 

 average of over twenty miles per hour. The 

 New Hampshire is a sister ship to the Maine, 

 recently built at Wilmington, for the Provi- 

 dence and Stonington Steamship Company, 

 which has also proven a great success, both 

 as a fast sailer and a most comfortable and 

 luxurious boat for passengers. 



Exchanges. 



[Free of charge to all, if of satisfactory character 

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



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 gold 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 S27, and is nearly new. 

 U. O. COX, Mankato, Minn. 



To exchange ; Experiment Station bulletins and 

 reports for bulletios and reports not in my file. I 

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

 ROLFS, Lake City, Florida. 



Finished specimens of all colors of Vermont marble for 

 fine fossils or crystals. 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," i8gi, S2.50,new 

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

 1S40; "The Sabbath," by A. A. Phelps, 1842; " History 

 of the Institution of the Sabbath Day, Its Uses and 

 Abuses," by VV. L. Fisher, 1859; " Humorous Phases of 

 the Law," by Irving Browne; or other works amounting 

 to value of books exchanged, on the question of govern- 

 mental legislation in reference to religion, personal liberty, 

 etc. If preferred, I will sell "American State Papers," 

 and buv other books on the subject. WILLIAM AD- 

 DISON BLAKELY, Chicago, 111. 



'lZf:l^^S^:'l:^'i^^::^fT..^l^it popular manual of visible speech and 



For Sale 

 chemical 



ance (200g. to i-iom?.),^ platinum dishes and crucible: 

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

 part or whole. Also complete file of Sillifnan's yourn 

 1862-1885 (62-71 bound); Smithsonian Reports, 1854-18 

 U. S. Coast Survey. 1854-1869. Full particulars to 1 

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



Wants, 



Any person seeking a position for -which he is quali- 

 ft-edby his scientific atiaininenfs^ or any person seeking 

 some one to fill a position of this character ^ be it that 

 of a teacher of science^ chemist^ draughts}nan, or what 

 not, may have the ' Want' inserted tinder this head 

 FREE OF COST, if he satisfies the publisher of the suit- 

 able character of his application, A ny person seeking 

 information on any scientific question^ the address of 

 auy scientific jnan^ or 'who can in any way use this 

 column for a purpose consonant 'with the nature of 

 the paper., is cordial y invited to do so. 



TRANSLATOR wanted to read German architec- 

 tural works at sieht (no writing). One familiar 

 with technical terms desired. Address ''A. .'"Box 

 149, New York Post Office. 



WANTED.— A position in a manufacturing estab- 

 lishment by a manufacturing Chemist of in- 

 ventive Hbility. 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 ex- 

 change. Also want medical battery and photo out- 

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



WANTED.— A college graduate with some normal 

 training, to teach the sciences, at SI. 800 per 

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

 ist preferred. Must also be a tirst-class Latin 

 scholar. A. H. Beals, Bos K, MilledgeviUe, Ga. 



A PROFESSORSHIP in Chemistry is wanted by 

 one who haa 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 studenfs laboratory. 

 Special points of strength claimed are: (1) Thorough 

 control of a class aod good order during lectures 

 and recitations. (2) 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, 874 Broadway, New York. 



ADDRESS WANTED.— Will some one please send 

 the address of the Secretary of the American 

 Philological Society. Also that of Herbert Spencer. 

 'ADDISON," Room 84, 164 Madison St., Chicago, III. 



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. 



VOCAL PHYSIOLOGY. 



For use in Colleges and Normal Schools. Price 50 cents 

 Sent free by post by 



N .D. €. HOOGES, 8 74 Broadway, N.Y. 



