268 



SCIENCE. 



[Vol. XIII. No. 322 



— Ginn & Co. announce, in the College Series of Greek Authors, 

 "Homer's Odyssey," Books I.-IV., based on the edition of Ameis- 

 Hentze, edited by Professor Perrin of Adelbert College, Cleveland. 

 The German edition has been freely changed to adapt it to the 

 needs of American college-classes, but record is made in the ap- 

 pendix of all important deviations from the opinions of the Ger- 

 man editors. References are rather liberally given to the leading 

 American grammars, and also to Monro's " Homeric Grammar." 

 As the gist of matter referred to is always given in the current 

 note, such references are usually meant for those Vifho desire to 

 collect further illustrative material. Much attention has been paid 

 to the indication or citation of iterati, conventional phrases, and 

 metrical formulae. The student should realize in some measure 

 both the bulk of this material and its bearing on the critical analy- 

 sis of the poem. The latest accepted views in Homeric archaeology 

 are presented. The appendix gives not only strictly critical data, 

 but also material which should enable a student with limited ap- 

 paratus to understand the historical and Uterary status of contro- 

 verted views. 



— The latitude of the Detroit Observatory, Ann Arbor, Mich, 

 has been determined by the Zenith telescope, and discussed by the 

 method of least squares, by Ludovic Estes, Ph.D., of the University 

 of Michigan. The results are published in pamphlet form by the 

 author. 



— P. Blakiston, Son, & Co., announce that the edition of " The 

 Hygiene of the Nursery," by Louis Starr, M.D., is exhausted. A 

 new edition is in press, and will be published about April i. The 

 author has taken this opportunity to rewrite certain parts of the 

 work, and to make some additions. 



— On or about April 6 will commence the publication of a weekly 

 journal, devoted to the petroleum and natural-gas resources of the 

 whole country, entitled The foternal of Oil and Gas. Situated 

 midway between the great gas-fields of Pennsylvania, Ohio, and 

 Indiana, and in the heart of Ohio oil-producing territory, with every 

 facility for the publication of a first-class journal, the publishers 

 (Fremont, O.) will spare no effort to make it the recognized au- 

 thority on gas and oil matters. 



— The admirers of " Little Lord Fauntleroy " will welcome the 

 leading article in this month's St. Nicholas, by Mrs. Lillie, telling 

 of httle Elsie Leslie Lyde, the child who is now interpreting the 

 character to New York audiences. There is an article meant for 

 boys, and describing with drawings and pictures " Ancient and 

 Modern Artillery," by Lieut. Hamilton, and (to thousands of com- 

 petitors a most interesting feature) the report awarding prizes in 

 the " King's Move " Puzzle. 



LETTERS TO THE EDITOR. 



*^*CorresJionde7its are requested to be as brief as possible. The writer's name is 

 in all cases required as proof of ^^ood faith. 



The editor ■will be glad to publish any queries consonant with the character of 

 the journal. 



Twenty copies of the number containing his communication will be furnishea 

 free to any correspondent on request. 



The Robinson Anemometer. 



It seems likely that there are now to be some rather interesting 

 developments in regard to the movement of this anemometer. As 

 to the use of an equation for representing the relation between the 

 wind-movement and travel of the cups, I think it a serious waste 

 of labor. Even if we have the equation given in last Science, it can- 

 not help us in obtaining the relation till we have solved it, and ob- 

 tained a table or the figures given in my letter published in Science 

 of March 15. 



Professor Marvin's explanation of the effect of a uniform wind 

 blowing across a whirler, upon which an anemometer is being 

 tested, is very surprising and entirely untenable. The anemometer 

 is certainly not going wzV/z the wind during one half of its revolution, 

 and against it during the other half. Suppose we carry an ane- 

 mometer on a locomotive due north, and a wind is blowing from 

 the north : the velocity registered by the anemometer will be the 

 sum of the two. But if the wind is from the south, the anemome- 

 ter will record the difference between the two. If the wind blows 

 either east or west, it will add its effect to the motion of the loco- 

 motive. We see, then, that, during less than one-fourth of the 



revolution of the whirler, a uniform current will be balanced on op- 

 posite sides, but during more than two-fourths of the revolution 

 the uniform current will act continuously in augmenting the ane- 

 mometer travel ; or, in other words, the anemometer will be accel- 

 erated during more than three-fourths of the rotation, and retarded 

 during less than one-fourth of it. This also explains why the heli- 

 coid anemometer used in England did not show variable results, as 

 it had a vane to keep it normal to the wind : the effect of the wind 

 would just be counterbalanced at opposite sides of the whirl, and 

 there would be no acceleration, as in the case of the Robinson 

 anemometer. 



Professor Marvin raises an interesting question as to the theo- 

 retical behavior of the cups in an intermittent wind. It has gen- 

 erally been considered that while these cups never respond instantly 

 to the wind, and continually lag behind while the wind is rising, 

 yet their momentum keeps them up, and about counterbalances 

 this lagging while the wind dies down. During the experiments 

 with the whirling arm it occurred to me that the wind might have 

 a different effect, and that it was necessary to make the final com- 

 parison in the open air. 



On March 23 a comparison was made between the regular Signal 

 Service anemometer, weighing sixteen ounces, and one with paper 

 cone-shaped cups of about the same dimensions, and weighing two 

 ounces and a half. The results were very surprising, as the paper 

 cones gave very nearly twenty per cent less velocity than the spheri- 

 cal ; also, with the lowest velocity, these cups gave relatively the 

 least wind. On watching the cups, it was plain that this diminu- 

 tion occurred with a uniform wind as well as with an intermittent 

 one. The cups were then weighted with lead to four times their 

 previous weight, and there was no difference in the result, showing 

 that the trouble was with the shape, and not with the lightness of 

 the cups. Paper cups were then made of a spherical form ; and 

 these gave almost exactly the same velocity as the metallic cups, 

 though having only one-seventh their weight. It was noticed, that, 

 with the most intermittent wind, the paper cups gave the most in- 

 crease, amounting in one case to eleven per cent over the metallic. 

 The higher the wind, in general, the more nearly did these cups 

 agree. We may rest satisfied, then, that the heavy metallic ane- 

 mometer, instead of giving too much wind, really gives too little ; 

 and the more gusty the wind, the less the movement recorded by 

 the heavy cups. H. A. Hazen. 



Washington, D.C., March 30. 



An Earthquake in Pennsylvania. 



It occurred to me that it might be of interest to the readers of 

 Science to know that an earthquake occurred at this place, 

 Lancaster City, Penn., on the 8th of March, at about 6 hours and 

 40 minutes p.m. This tremor was felt also at Harrisburg, York, 

 Philadelphia, and Reading, as well as at many other places within 

 the community of these places. Never having felt an earthquake- 

 shock myself, it did not at once occur to me that this was really an 

 earthquake, and therefore I did niot at once take the time of its oc- 

 currence. That evening and the next morning I tried to find per- 

 sons who did look at their time-pieces at the moment when it 

 occurred in order to find the time as accurately as possible. Alto- 

 gether, seven persons were found who claim to have looked at their 

 watches when it occurred. Of these, two are quite different from 

 the others, and must be considerably in error. But five of them 

 agree fairly well. I compared each one of those time-pieces with 

 my own, which was compared with the Scholl Observatory clock. 

 Making in this way all possible corrections, the mean of the times 

 was found to be 6 hours 40 ^^ minutes p.m., with a probable error of 

 only about two-tenths of a minute. This is 75 Meridian time. If the 

 tremor did not have too high a velocity, and similar observations 

 have been gathered at other places, it may be possible to get at an 

 estimate of the velocity and direction of the shock. 



The tremor or trembling of the earth, according to my estimate, 

 lasted about ten seconds. A number of persons agree with this 

 estimate. Others, however, insist that it lasted about fifty seconds, 

 as actually noted by the watch. The direction of the tremor seemed 

 to be in a line a little north of west to south of east. Others also 

 give it as north and south. JEFFERSON E. KerSHNER. 



Lancaster, Penn., March 26. 



