SCIENCE. 



255 



served on at least three occasions, and has been suspected, 

 without being positively identified, a much larger number 

 of times. 



The Transit Circle was made by Troughton and Simms, 

 London, in 1876 and was mounted in 1877. The con- 

 struction of the instrument and the method of mounting 

 are quite similar to the instruments in use at Greenwich, 

 and Haivard College Observaorv. 



The telescope has a clear aperture of 6 inches, and a 

 focal length ot 6 feet 4 inches. The axis is cast in a 

 single piece, into which fit the steel pivots, 3.50 inches 

 in diameter. The Y's are of gun metal, and their bear- 

 ing surfaces 2.50 inches long, 0.74 inches wide. The piers 

 are of iron, and are firmly bolted to heavy stone caps 

 which rest upon brick foundations. The circles are 24 

 inches in diameter, divided to 5', and read by four micro- 

 scopes each. 



The reticule in the focus of the telescope carries 15 

 vettical and 5 horizontal threads — the vertical threads 

 being all carried by the Right Ascension micrometer 

 screw, and the horizontal threads by the declination 

 screw. There are no fixed threads in the field. 



The Transit Circle is furnished with two collimators 

 having object glasses of 4 It. 3 in. focal length and 4.33 

 in. aperture. The distance between the bearing points 

 of the collimator Y's is 3 ft. 10 in. In the focus of each 

 collimator are fixed two close vertical threads (about 5.3" 

 apart) and one horizontal thread. In the ordinary time 

 observations it is customary to observe for collimation 

 immediately before the observations cf star transits, and 

 then set the micrometer so as to destroy the error in 

 collimation. 



The Standard Sidereal Clock of the Observatory is 

 Frodsham No. 1369. It was mounted in 1877, and has 

 been running for two years past on a very small and con- 

 stant rate. 



In addition to these instruments, the Observatory is 

 furnished with an excellent 4-in. Clark Comet Seeker, an 

 Altazimuth by Gasella, and the usual barometers, ther- 

 mometers, etc. 



The work now being carried on is chiefly equatorial, 

 and may be divided into two parts, as follows : 



1. Double Star Work. A list consisting chiefly of 

 binaries which have been neglected for some years (some 

 of them for ten or twenty, or even thirty years) and will 

 well repay observation. Besides these, a selected list of 

 Burnham's stars, which are suspected of binarity, or which 

 are quite new and have not been observed. Most of these 

 stars are in the southern sky, and including the list for 

 personal equation, will make a total of about 500 doubles. 

 This work is well under way and will probably be con- 

 cluded vithin a year. 



2. The second part of the equatorial work consists of 

 observations, descriptive and micrometric, upon planets 

 and their satellites, and includes a series of observations 

 extending over several years, upon the satellites of Saturn, 

 and observations upon the red spot of Jupiter since its 

 discovery at Glasgow in 1878. 



With the Meridian Circle, no work is done beyond the 

 ordinary observations for time. 



The Time- Service of the Observatory, inaugurated 

 within the past year by Prof. H. S. Pritchett. has met 

 with well deserved success, and its value is fully appre- 

 ciated by the people of the State, Two time balls are 

 dropped by the Observatoiy clock — one in St. Louts and 

 one in Kansas City — and the clock signals are regularly 

 distributed over a large and constantly increasing area. 

 Owing to its position — almost exactly one hour west of 

 Washington — the Morrison Observatory will doubtless 

 be largely depended upon in regulating the time of the 

 Mississippi Valley, if any of the schemes for " Uniform 

 Time" which have recently been proposed are ever 

 adopted. 



Though so well equipped instrumentally, Morrison Ob- 

 servatory, like many a similar institution of longer stand- 



ing, is sadly crippled for want of funds : its income being 

 barely sufficient for the support of a director without as- 

 sistance. It is greatly to be regretted that one of the 

 most promising observatories in the country should 

 be thus curtailed in its usefulness, merely for want of 

 proper financial support. W. C. W. 



DISCOVERY OF AN ASTEROID. 

 The Smithsonian Institution has received from M. 

 Foerster, of Berlin, the announcement of the discovery 

 by M. Palisa, at Pola, on the 20th of May, 1 881, of a 

 planetoid of the thirteenth magnitude, in 

 R. A. 1 5h 3m 

 Dec. — 23 2' 

 with a daily motion of 8 m north. 



CORRESPONDENCE. 



\_The Editor does not hold himself responsible for opinions expressed 

 by his correspondents. No notice is taken of anonymous communi 

 cations.] 



LOCUSTS AND SUN SPOTS. 

 To the Editor of "SCIENCE:" 



Sir: It may concern some of your readers to know 

 that I have just made the interesting discovery, that the 

 multiplication and migration of the Rocky Mountain 

 Lccust {Caloptcnus spretus), has been hitherto in exact 

 agreement with the minima of Wolf's sun spot cycles as 

 given (Mem. As. Soc. vols. XLI1 and XLIII), and its de- 

 crease has as nearly accorded with the maxima, there not 

 being a year's difference. On European areas, it may be 

 remarked, insect migration but rarely agrees with these 

 maxima and minima, the chief periods being obtainable 

 by counting the elevens since 1846. There likewise exists 

 this marked difference, in that while the American locust 

 spreads to the east and west of south, European mi- 

 grants come north and east. 



It would be important to determine the multiplication 

 of the Corn Weevils in relation to the sun spots. Cannot 

 the trade keep diaries ? As the more destructive kind 

 comes from the tropic, the minimum period should be 

 dreaded. A. H. SwiNTON. 



Guildford, Eng., May, 1881. 



THE VIEWS OF DR. HOLMES UPON THE PRO- 

 POSED REVISION MODIFICATIONS OF AN- 

 ATOMICAL NOMENCLATURE. 



We are permitted to publish the following letter from 

 Oliver Wendell Holmes to Professor B. G. Wilder re- 

 specting the articles on "Anatomical Nomenclature" 

 which appeared in Nos. 38 and 39 of this journal. It 

 may not be generally known to our readers that " The 

 Autocrat of the Breakfast-table " has been for many 

 years the Professor of Anatomy in the Harvard Medical 

 School. Boston, May 3, 188 1. 



Di ar Dr. Wilder : 



1 have read carefully your papers on Nomenclature. I 

 entirely approve of it as an attempt, an attempt which I 

 hope will be partially successful, for no such sweeping 

 change is, I think, ever adopted as a whole. But I am 

 struck with the reasonableness of the system of changes 

 you propose, and the fitness of many of the special terms 

 you have suggested. 



The last thing an old teacher wants is, as you know 

 full well, a new set of terms" for a familiar set of objects. 

 It is hard instructing ancient canine individuals in new 

 devices. It is hard teaching old professors new tricks. 

 So my approbation of your attempt is a sic vos nott 

 vobis case so far as I am concerned. There is one term 

 which I do not quite fancy, pero, which you couple with 

 pes in naming the rhinencephalic lobe. I should prefer 

 the old term bitlbus with theca unless there is some ob- 

 jection I do not see. 



What you have to do is to keep agitating the subject, 



