NOTES UPON THE FUNDAMENTAL SYSTEM 



OE STARS. 



By F. A. BliLLAMY. Hox. M.A., F.R.A.S. 



Owing to the unfortunate dela_v, mentioned in the 

 last number of " Knowledge," Professor Boss" 

 arranged second visit to San Luiz, with the other 

 members of the observing staff, Mr. A. J. Roy, Mr. 

 Sanford, Mr. Zimmer, Mr. Fair. Mr. Gibble and Mr. 

 Delavan, and witli the instruments, was postponed to 

 Januar\-, 1909, b\' which time it was expected tiiat the 

 observatory buildings would be read\- for the instru- 

 ments. Among the instruments were the Olcott 

 meridian-circle, clock, chronographs, photometer, antl 

 other necessary apparatus. Immediately on arrival 

 at San Luiz the various instruments were erected, and 

 preliminary work was started. When the necessary 

 adjustments were effected the actual programme 

 of work, carefully arranged at Alban\-, was begun by 

 the obser\'ers, and will be continued until completion; 

 the \\hoIe work of observation was then expected to 

 take about three years from the time of commence- 

 ment (April, 1909). Professor R. H. Tucker will 

 be left in entire charge of the obser\att)ry and work. 

 This astronomer, who is probabh- the most skilled 

 observer in meridional astronom\-, is the assistant in 

 charge of the meridian-circle at the Lick Observator}', 

 and has been granted leave of absence from there 

 for the express purpose of assisting in this 

 important investigation. Professor Tucker was an 

 assistant at the Albany Observatory thirt}- years 

 ago ; he was also the chief assistant for many 

 years at the national observatory at Cordoba. 

 Argentina, later on joining the staff at the Lick 

 Observatory, where he has been for ten \-ears 

 engaged in important meridian work. Mr. Rov 

 and Mr. Varnum are the two senior assistants at 

 Albany, and are experienced observers with the par- 

 ticular instrument which is being used at San Luiz ; 

 moreover, it was thev who largely contributed to 

 the Albany observations of 1907-8 ; so we mas- 

 hope for excellent and homogeneous results. 



Owing to the extreineh' dr\- climate of San Luiz, 

 the vegetation is scanty, except in places where resort 

 is had to irrigation. The plot upon which the 

 observatory stands is under irrigation and is covered 

 with a luxuriant growth of nlfalfa^ : the effect of this 

 is of great importance, as it protects the soil and 

 reduces the variations of radiation to a minimum, a 

 most essential point to be considered in astronomical 

 observations at low altitudes. The soil, under the 

 rich surface la}'er of vegetable mould, is a sandy 

 loam from three to five feet in thickness: under this is 



a layer of gravel of similar thickness, and below that 

 a dry and hardened chn- : this is considered to offer 

 an ideal foundation for the piers of a meridian-circle. 

 Within a week the true meridian was settled, plans 

 were made ft)r foundations, and the site was soon 

 covered with bricks and mortar. The transit room, 

 22-ft. X 23-ft., is of brick, with a wooden roof; the 

 office rooms, of one story, are of brickwith agalvanized 

 iron roof ; the exterior dimensions are about SO-ft. by 

 60-ft., the central portion being arranged on the usual 

 Spanish method with an interior court, or patio. The 

 first stone was laid on October 5th, with a little 

 ceremony, in the presence of officials and friends. 



Having gi\-en a brief and general account of the 

 causes which niaile this great piece of astronomical 

 work necessary, and Imw it became possible to 

 accomplish it. we will complete this article b}- 

 giving a translation, containing more details, 

 of a paper in Spanish read b\- Professor Tucker, 

 before the American International Scientific 

 Congress, held at Buenos Aires, Argentina, printed 

 at the expense of the Department of Meridional 

 Astrometr\- of the Carnegie Institution of Washing- 

 ton. U.S.A. American astronomers are greath' 

 indebted to the munificent generosity of Mr. 

 Carnegie for providing the mone\-, without which 

 this, Pasadena, and other astronomical researches 

 could not be made, or, at least, could not be carried 

 ciut so speedih' or eftectix'ely. 



The Fundamentai. System of Stars. + 



There are two great and permanent problems in 

 astronom}-. One concerns the positions of the 

 bodies visible in the Uni\erse. and the other relates 

 to the form, history, and constitution of those bodies. 

 Of the second problem, the chemical constitution 

 and the history of the evolution of the stars, the 

 sun, planets, nebulae, and comets, are keeping the 

 great telescopes, the photographic [ilates. and the 

 spectroscopes, and other instruments well employed 

 for their investigation : these instruments are of 

 modern form. 



For the first problem the Meridian Circle, 

 though much older, has until now been the most 

 perfect and most used instrument, though of less 

 power, for the determination of the positions of these 

 bodies. For the regular observations of transits of the 

 stars, an instrument of this form has been erected 

 in every case in the great observatories of the world. 



This is a species of lucerne. 

 i El Sistciiui Fmuhjincntnl dc las EstrcUas. para 



H. Tucker, Observatorio dc San L\iiz, 

 F. A. Bellamy. 



lylO, June 30th; translated 



131 



