442 



SCIENCE. 



[Vol. XIII. No. 331 



SCIENCE: 



A WEEKLY NEWSPAPER OF ALL THE ARTS AND SCIENCES. 



PUBLISHED BY 



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Vol. XIII. 



NEW YORK, June 7, li 



No. 331. 



CONTENTS 



'Some New Electric Motors 431 



Watsr-Filtration 



• JoJl71 a. Caldwell 432 

 The Use of Spirit as an Agent 



IN Prime Movers 433 



West Indian Hurricanes 434 



Electrical News. 



The Average Efficiency of Incan- 

 descent Lamps 435 



Inherent Defects of Lead Secondary 

 Batteries 436 



Health M 

 Women's 



Asphyxiation by Illuminating-Gas. 437 

 Cancer Contagion 437 



Notes . 



• News 437 



JIditorial 442 



/Preliminary Work on the Next Cen- 

 sus. — Science, Falsely so called. 



Recent Discoveries in Central 



Africa 442 



A Sandy Simoom in the North- 

 west 444 



The Spider-Bite Question 444 



Book-Reviews. 



A Text-Book of Pathology, Sys- 

 tematic and Practical 445 



Elementary Text-Book of Zoology. 445 



Pestalozzi ; his A im and Work 445 



The Electric Motor and its Appli- 

 cations 446 



Examination of Water for Sanitary 



and Technical Purposes 446 



The Bacteria in Asiatic Cholera.... 446 

 First Book of Nature 446 



Among the Publishers . . 446 



Letters to the Editor. 

 A New Chemical Experiment 



y> R. JLaton 449 

 Relative Frequency of Letters and 

 Combinations H. y. T. 449 



The VARIOUS medical associations and the medical pro- 

 fession will be glad to learn that Dr. John S. Billings, surgeon in 

 the United States Army, has consented to take charge of the " Re- 

 .port on the Mortality and Vital Statistics of the United States," as 

 returned by the eleventh census. As the United States has no 

 ■system of registration of vital statistics, such as is relied upon by 

 • other civilized nations for the purpose of ascertaining the actual 

 rmovement of population, our census affords the only opportunity of 

 obtaining any thing near an approximate estimate of the birth and 

 'death rates of much the larger part of the country, which is en- 

 vtirely unprovided with any satisfactory system of State and muni- 

 'Cipal registration. In view of this, the Census Office, during the 

 month of May this year, will issue to the medical profession through- 

 out the country ' physician's registers ' for the purpose of obtaining 

 more accurate returns of deaths than it is possible for the enumer- 

 ators to make. It is earnestly hoped that physicians in every part 

 of the country will co-operate with the Census Office in this im- 

 portant work. The record should be kept from June i, 1889, to 

 May 31, 1890. Nearly 26,000 of these registration-books were 

 filled up and returned to the office in 1880, and nearly all of them 

 lused for statistical purposes. It is hoped that double this number 

 will be obtained for the eleventh census. Physicians not receiving 

 registers can obtain them by sending their names and addresses to 

 ithe Census Office ; and with the register, an official envelope, which 



requires no stamp, will be provided for their return to Washington. 

 If all medical and surgical practitioners throughout the country will 

 lend their aid, the mortality and vital statistics of the eleventh census 

 will be more comprehensive and complete than they have ever been. 

 Every physician should take a personal pride in having this report 

 as full and accurate as it is possible to make it. All information 

 obtained through this source will be held strictly confidential. It 

 is equally important to the country that the returns in relation to 

 farm-products and live-stock should be full and correct. The 

 enumerator in the house-to-house visit he will make during the 

 month of June, 1890, is constantly met with the fact that farmers 

 keep no books, and hence returns are not infrequently guess work. 

 The census year begins June i next, and ends May 31, 1890. If 

 farmers throughout the country would note this fact, and keep 

 account of the products of their farms during the census year, it 

 would be of material aid in securing reliable returns for the eleventh 

 census. 



Some one recently sent Professor C. M. Woodward, direc- 

 tor of the Manual Training School, Washington University, St. 

 Louis, Mo., a copy of a small periodical called " Microcosm," in 

 which there was a prize essay by a Mr. Reuben Hawkins of Chil- 

 licothe, Mo., which has some interest. This article Professor 

 Woodward picks to pieces in The Teacher for May. The author 

 begins by quoting the familiar ideal experiment of firing a cannon- 

 ball horizontally from the top of a tower, under the assumption 

 that the force of gravity is constant, and that there is no resisting 

 medium. The question is as to the time occupied in reaching a 

 lower horizontal plane. Mr. Hawkins says that the common an- 

 swer that the time occupied by the projectile is the same as the 

 time occupied by a ball falling vertically from the muzzle of the gun 

 to the same horizontal plane, is wrong, and his prize money is won 

 by an argument in support of his assertion. Professor Woodward 

 states that he has no idea who Mr. Hawkins is, nor does he know 

 what facilities he has had for acquiring correct notions of mechan- 

 ics and correct methods of reasoning, and had his essay not been 

 indorsed by the editor, A. Wilford Hall, Ph.D., LL.D., in a com- 

 mendatory note as well as by a prize, he should not have spent a 

 moment on it. But when he sees such unspeakable trash com- 

 mended and rewarded by a man who claims to have some under- 

 standing of the principles of physics, he feels constrained to pro- 

 test. Mr. Hawkins's argument begins with some propositions in 

 regard to the resultant of two forces acting on the same body, sub- 

 stantially as follows : If two equal forces act in direct opposition, 

 the resultant is nothing. If two equal forces act in the same di- 

 rection or in conjunction, the resultant is equal to their sum, or 

 twice one of the component forces. Now, if one of the forces is 

 turned to a mean position between the two just considered, that is, 

 to a position at right angles to the second force, or in " half posi- 

 tion " as Mr. Hawkins calls it, the resultant must be the mean of 

 the former resultants. The mean of zero and two is one. Hence 

 the resultant of two forces at right angles to each other is just 

 equal to one of them. All this, and more of the same kind, Dr. 

 Hall indorses as follows : " The foregoing article from the able 

 pen of Mr. Hawkins was written substantially before our prize offer 

 was published. From its highly scientific character, however, and 

 from the fact that this number of the Microcosm will reach more 

 than twenty thousand professors and teachers, we deemed it im- 

 portant to give it the position of Prize Essay No. i." How far 

 such teaching may do mischief is a question, but its existence is 

 worthy of occasional note. 



RECENT DISCOVERIES IN CENTRAL AFRICA. 



The results of Van Gele's exploration of the Obangi, of Junker's 

 discoveries on the Upper Welle, Stanley's great journey up the 

 Aruvimi, and Delcommune's ascent of the Lomami, have materi- 

 ally added to our knowledge of Central Africa, the river systems of 



