346 JOSEPH WINLOCK. 



instruments, and of the best class. These little instruments divided 

 with tlie larger ones the benefits of his inventive spirit. In his two 

 eclipse expeditions, he provided abundantly for the spectroscopic exam- 

 ination of the sun's surroundings, catching the sun itself in the reversal- 

 of the lines, and witnessing other interesting transformations. The 

 secret of his success lies in the direction of his rule of having a definite 

 idea of what he wished to do, and the best way of doing it, before 

 going into the field. He went to Spain with the purpose of studying 

 especially that feiinter portion of the si;n's corona wliich is outside the 

 limits of the best photography. His experience in the Kentucky 

 expedition had taught him that much valuable time is lost in the brief 

 duration of totality, when the position of the dark or bright lines is 

 registered by means of a scale which must be read and recorded at 

 the time. To meet tliis difficulty, he invented the simple expedient 

 of graving corresponding lines upon a silver plate, previously graduated 

 by a few standard spectral lines. The diffisrences could be leisurely 

 measured at some future time. This improvement was promptly 

 adopted by the English astronomers, and applied by them to the 

 eclipse of 1870. Mr. Winlock was of opinion that his contrivance 

 would be useful in observing the spectra of comets and nebulos, and 

 wherever the lines were faint. It might also be convenient for finding 

 declination with meridian instruments. Another device was the use 

 of a mirror to reflect the slit, and enable the observer to place it 

 upon any part of the sun's image without the help of an assistant. 



In January, 1854, the Hon. R. C. Winthrop, Chairman of the Com- 

 mittee of the Board of Overseers of Harvard College, appointed to 

 visit the Observatory, reported that the Observatory time was sent to 

 Boston for the regulation of marine chronometers, for the arrange- 

 ment of railroads, and for the general convenience of the people 

 through a large part of New Plngland. He adds : " The impor- 

 tance of such a system to the business operations of the community can 

 hardly be ovex'-estimated." At this time the signals were sent to 

 Boston by way of Watertown, Brighton, and Roxbury, a circuitous 

 line of twelve miles in length, and the wires were often broken. In 

 185G, a loop connected the Observatory with the Fitchburg line, and 

 was owned by it until 18G2. This has, of course, been available for 

 the occasional transmission of time ; but it was designed for the deter- 

 mination of diiferences of geographical longitude, in connection with 

 the United States Coast Survey ; a service which begin under the 

 administration of the first Director, and has been continually expand- 

 ing, until it has taken into its embrace the Pacific coast and the 



