208 



THE POPULAR SCIENCE MONTHLY 



mined a century and a half ago, but the 

 chronograph, known for many years as 

 the American method, is only half a cen- 

 tury old. 



One of the greatest astronomical re- 

 searches has been the measurement of 

 the exact positions of 166,000 stars. 

 The sky was divided into twenty zones 

 of which seven were taken by Germany, 

 four by the United States and three 

 by Eussia. Of the American zones 

 two were observed at Cambridge, one 

 at Albany, and one at Washington. 

 Each occupied the time of several 

 astronomers for twenty years. It is 

 now nearly time, after fifty years, to 

 reobserve these stars to determine their 

 motions. Fortunately, two new meth- 

 ods, the transit micrometer and photog- 

 raphy, have been found which will 

 greatly reduce the labor. The older de- 

 partment of astronomy, measuring the 

 positions of the stars, has been left in 

 America to the Naval Observatory. 

 Unfortunately, the law requires that the 

 superintendent must be a naval officer 

 who can not remain long on land. The 

 average term of office is less than two 

 years. The average term at Greenwich 

 is thirty years, where with but half the 

 income, more than double the work is 

 i lone. Congress, though repeatedly ap- 

 pealed to, will not remedy this great 

 waste of the public funds. 



Two million measures of the light of 

 S0,000 stars have been made at Harvard. 

 The results have been accepted by an 

 international committee as the standard 

 for the world. Such measures are likely 

 in the future to be replaced by photo- 

 graphs taken with yellow light. A cer- 

 tain class of stars vary in brightness. 

 Some increase in light many thousand 

 times, others double their brightness in 

 seven minutes with perfect regularity. 

 Many thousand excellent observations 

 of these objects are now obtained every 

 year by amateurs having only small 

 telescopes. Nearly five thousand vari- 

 able stars are known of which three 

 quarters have been found at Harvard. 

 Astronomical photography, and Ameri- 



can invention, replaces eye observations 

 in almost all researches. Two Harvard 

 telescopes have each taken 40,000 photo- 

 graphs whose combined weight is about 

 forty tons. They give the only record 

 on the earth of the history of the stars 

 for the last quarter of a century. Pho- 

 tographs of the spectra of the stars to 

 determine their motions form the prin- 

 cipal work of the Lick, Yerkes, Green- 

 wich, Potsdam and many other of the 

 larger observatories. A catalogue of the 

 spectra of 200,000 stars is now being 

 compiled at Harvard, and will fill seven 

 large quarto volumes. 



The friendly cooperation of Ameri- 

 can astronomers has greatly advanced 

 the work in this country, but it will be 

 difficult to compete with the splendid 

 observatories and instruments now lav- 

 ishly furnished in Germany. If similar 

 support is given us, the American As- 

 sociation for the Advancement of Sci- 

 ence can fulfill its objects as regards 

 astronomy. 



SCIENTIFIC ITEMS 

 Science in America has during the 

 past month lost three of its most dis- 

 tinguished leaders — Dr. S. Weir Mitchell, 

 the eminent physician, physiologist and 

 man of letters, of Philadelphia; Dr, 

 Seth C. Chandler, the astronomer of 

 Cambridge, and Dr. Benjamin Osgood 

 Peiree, Hollis professor of mathematics 

 and natural philosophy at Harvard Uni- 

 versity. 



Dr. Charles Budd Robinson, eco- 

 nomic 1 otan : st of the Bureau of Science 

 of the Philippine Islands has been killed 

 by natives in the Amboyna Islands in 

 the Malay Archipelago. 



It is proposed to place a suitable me- 

 morial of the late Alfred Eussel Wal- 

 lace in Westminster Abbey. It is also 

 proposed to present a statue or bust to 

 the British Museum of Natural History 

 and a portrait to the Royal Society. 

 Contributions to the Alfred Russel Wal- 

 lace Memorial Fund may be sent to the 

 London and Smith Bank, Holborn Cir- 

 cus, London, E.C. 



