SCIENCE 



[N. S. Vol. XLIV. No. 1147 



of the method of examining nursery stock in the 

 District of Columbia, and it was shown that such 

 stock was naturally divided into commercial ma- 

 terial, including plants and plant products re- 

 ceived by florists, department stores and private 

 individuals; and departmental material, including 

 plants and plant products introduced by the vari- 

 ous offices of the Department of Agriculture, more 

 particularly the Office of Foreign Seed and Plant 

 Introduction. Some time was devoted to discuss- 

 ing the new method of disinfecting cotton, and 

 lantern slides were shown exhibiting the plants 

 which are now operating in Boston, Mass., Brook- 

 lyn, N. T., Newark, N. J. and Oakland, Calif. 

 An Outline of the Glow-worms of the American 

 Family Phengodidw : H. S. Barber. 



M. W. Lyon, Jr., 

 Recording Secretary 



THE AMERICAN ASSOCIATION OF 

 VARIABLE STAR OBSERVERS 



On November 18, 1916, the American Asso- 

 ciation of Variable Star Observers held its 

 fourth annual meeting at the Harvard College 

 Observatory, Cambridge, Mass., at the invita- 

 tion of the director, Dr. E. C. Pickering. The 

 meeting was called to order in the library of 

 the institution at three o'clock with twenty- 

 two members present. The results of the 

 previous year's work were carefully discussed 

 and more definite plans adopted for the future 

 course of the association. Numerous light 

 curves and plottings pertaining to the work 

 were on exhibition, illustrating the observa- 

 tions on variable stars, particularly those of 

 long period. 



Later, a tour of the observatory was made, 

 at which time Professor Pickering and Miss 

 Cannon explained in detail the work of the 

 astro-photographic department, and Professor 

 King explained the manipulation of the differ- 

 ent photographic telescopes. This was followed 

 by a lantern-slide exhibition of views of Are- 

 quipa, Peru, and the work of the Southern 

 Station of the Harvard College Observatory 

 by Mr. Campbell. 



The meeting then adjourned to the commo- 

 dious quarters of the 12-inch polar telescope, 

 when nineteen experienced observers had the 

 unique opportunity of observing the same 

 variable star, SS Cygni, under like conditions, 



with an average deviation between observers 

 of only 0.14 magnitude. 



Prom seven until ten o'clock Professor Pick- 

 ering acted as host at a dinner given to the 

 members of the association. Following the 

 dinner many of the members enjoyed the op- 

 portunity of observing with the historic 15- 

 ineh equatorial until the wee sma' hours of 

 the morning. 



The next day a small party availed them- 

 selves of the chance to visit the well-equipped 

 students observatory at Wellesley College, by 

 the courtesy of the director, Dr. J. C. Duncan. 

 In no period in the history of astronomy has 

 an opportunity offered itself, as at the present 

 time, whereby a group of amateur astronomers 

 has been able to combine and organize them- 

 selves for such useful scientific work. In fact 

 no other branch of science offers this possibility 

 so completely, in which a two-fold purpose is 

 so well accomplished, namely : service and con- 

 tribution to science and personal pleasure to 

 those taking part therein. 



Not all the problems of astronomy are so 

 easily adaptable or inviting to amateurs, as this 

 study of variable stars. Nevertheless, in the 

 past five years a most productive field of re- 

 search has been developed, and one which has 

 called together one of the most enthusiastic 

 assemblages of men and women, some forty in 

 number and from all the different walks of life. 

 The study of variable stars is one of the old- 

 est branches of astrophysical astronomy, and it 

 was not until twenty-five years ago that syste- 

 matic work was undertaken. To this work the 

 Harvard College Observatory has devoted, 

 under the directorship of Dr. E. C. Pickering, 

 the greater part of its time and resources. 

 The methods and results in this study have 

 proved so simple and attractive that it has lent 

 itself admirably to non-technically trained as- 

 tronomers, with the result that in 1911 there 

 was formed this association of amateur ob- 

 servers, with Mr. Wm. Tyler Olcott as its sec- 

 retary and prime mover. Prom the character 

 of the work thus far performed, a number of 

 its members have recently received recogni- 

 tion by election to membership in the Ameri- 

 can Astronomical Society. P. E. B. 



