SCIENCE. 



445 



TIME SERVICE OF CARLETON COLLEGE OB- 

 SERVATORY, AT NORTHFIELD, MINNESOTA.* 

 William W. Payne. 



The observatory of Carleton College is located at 

 Northfield, Minn., forty miles south of St. Paul, on one 

 of the main lines of the Chicago, Milwaukee and St. 

 Paul Railway. It was built in 1878. Its latitude was 

 determined by Professor B. F. Thomas in 1879, by a 

 series of observations made with a Wurdemann zenith 

 telescope of two-inch aperture loaned to the Observatory 

 for that purpose by Lieut. Edward Maguier, Chief Engi- 

 neer of the Department of Dakota. He used the Talcott 

 method aud found the latitude to be 44° 27' 41" ±. In 

 August, 1880, the work was done a second time by 

 myself, using the same instrument and method, and ob- 

 serving forty pairs of stars from Sofford's catalogue on 

 three different nights. After the proper reductions the 

 latitude was found to be 44 27' 40. "8. 



In October, 1880, by the aid and courtesy of the officer 

 just named, and Lieut. O. B. Wheeler, of the Lake Survey 

 Corps, the longitude of the observatory was determined. 

 The Coast Survey meridian of St. Paul was used as the 

 base of operation. Observations were taken at both 

 points on two different nights and telegraphic signals 

 were exchanged. Independent reduction of the observa- 

 tions showed the longitude of the Observatory to be 

 i'i 4m 23 s . 85 west of Washington and 14.3 seconds west 

 of the meridian of St. Paul. 



INSTRUMENTS. 



The Observatory is furnished with the following instru- 

 ments : 



A Clark Equatorial, 8i-inch aperture, io£ feet, with 

 complete mounting. 



A Byrne Equatorial, 4.3-inch aperture, with portable 

 mounting. 



A Transit made by Fauth & Co., Washington ; teles- 

 cope of 3-inch aperture and 42-inch focal length with 

 reversing apparatus. 



Two Howard clocks with electric and magnetic at- 

 tachments for use in regulating and sending time. 



A Bond Siderial Chronometer with break-circuit and 

 an ordinary Clark Chronograph. 



TIME SERVICE. 



The time service of the Observatory began October 23, 

 1878, immediately after the clock wadset and regulated, 

 the N. W. Telegraph Company (now Western Union) 

 having previously asked for time, and having built a line 

 to the Observatory and furnished it with a telegraph 

 office. 



The electrical time-signals are given by the mean time 

 clock which has a break-circuit attachment operated by 

 a small wheel on the shaft carrying the seconds hand. 

 This wheel, which contains thirty-one teeth, spaced to 

 represent two seconds except three which give continu- 

 ous seconds to mark the close of each minute. This 

 clock is placed in a local circuit with appliances for cut- 

 ting it into the main telegraph lines for daily, noon 

 signals. By arrangement with the railroad companies 

 the clock is put into line before twelve daily and thus 

 give three full minute signals, the last stroke of the third 

 minute being the time of twelve exactly. 



Until recently the distribution of the time has been 

 effected in the following manner : 



The principal officers of five of the seven different rail- 

 roads centering in St. Paul and Minneapolis were con- 

 nected with the main office of the Chicago, Milwaukee, 

 and St. Paul Railway either directly or at some intersect- 

 ing point, and in this way our central mean time clock 

 has daily operated all the main lines of these companies. 

 The branch lines use the same time, having it repeated by 



*Read before the A. A. A. S., Cincinnati, t83i. 



hand. When the main lines are thus connected the 

 clock has given its break-circuit signal distinctly over 

 1285 of wire in six different States and territories and 

 ranging from Kansas City to St. Paul, Winona and Mc- 

 Gregor in Iowa. 



For a few weeks recently, the signal has been modi- 

 fied by reversing the points of the relay in the local cir- 

 cuit for the purpose of a make circuit signal on the main 

 line. A five minute signal attachment has also been ap- 

 plied to the clock that time balls may be dropped at 

 noon daily in connection with our railroad time service. 

 Arrangemenis are already made to drop a time ball in 

 each of the cities of St. Paul and Minneapolis, apparatus 

 for the same being already in hand. 



The five-minute attachment, as it is called, that aids in 

 dropping these time-balls, is a plain disk attached to the 

 train of the clock so as to revolve once in five minutes ; a 

 portion of the circumference representing fourteen seconds 

 is cut away. This disk is placed in the local circuit and 

 serves to keep it closed, and hence main lines open during 

 fourteen seconds preceding the sixtieth one before noon. 

 The interval gives opportunity to connect time-balls with 

 electrical apparatus for dropping the same by the single 

 twelve o'clock stroke from the clock. The dropping ap- 

 paratus that I use for these balls is manufactured by 

 Prof. H. S. Pritchett, of St. Louis. It is neat, simple and 

 effective. 



DISTRIBUTION OF THE TIME. 



The following railroad companies take the Northfield 

 meridian time directly or indirectly, and use it over their 

 lines without change. 



Miles. 



1. C. M.and St. P. R'y, on its five divisions West 

 of the Mississippi now embracing an aggregate 



length of 2271 



2. W. & St. Peter R'y, (branch of N. W. R'y,) 

 uses both Northfield and Barabvo signals but runs 



on Northfield time West of the Missisippi 484 



3. St. P. M. & O. from Sioux city to Elroy Wis., on 



all its branches 963 



4. M. & St. L. R'y, from Minneapolis South. . . . 260 



5. Northern Pacific Railway to the end of its 

 track 680 



6. St. P. M. & M. certainly to St. Vincent and (I 

 think to Winnepeg) 630 



7. St. P. & Duluth 153 



Making a total of 5541 



The last two companies named do not take time 



directly from the observatory but from jewelers in the 

 city of St. Paul who receive our daily signals. 



It will be seen readily by inspecting a map that the 

 territory traversed by these great railroads embraces ?.ll 

 of Minnesota and forts of Iowa, Nebraska, Dakota, Wis- 

 consin, Montana, and probably the Province of Manitoba. 



CHANGES IN MYA AND LUNATIA SINCE THE 

 DEPOSITION OF THE NEW ENGLAND 

 SHELL HEAPS* 



By Prof. Edward S. Morse. 



This communication embraced a comparison between 

 the shells peculiar to the ancient deposits made by the 

 Indians along the coast of New England, and similar 

 species living on the coast at the present time. Mr. 

 Morse referred to similar comparisons which he had 

 made in Japan, wherein he had found marked changes 

 to have taken place ; changes which showed that the 

 proportions of the shells had greatly altered. 



He had made a large number of measurements of shells 

 from a few shell heaps of Maine and Massachusetts, and 

 had obtained very interesting results. The common 



*Read before the A. A. A. S., Cincinnati, 1881. 



