February 27, 1903. J 



SCIENCE. 



333 



observations so well as the preliminary 

 elliptic orbit. In determining the final 

 elliptic orbit many difficulties were en- 

 countered which led to the theoretical re- 

 sults given in the foregoing papers. The 

 calculation of an orbit irrespective of 

 parallax and aberration has just been un- 

 dertaken. A preliminary improvement of 

 the orbit gave evidence that the first re- 

 sults concerning a very short period will 

 be substantiated. The following students 

 and assistants have taken part in the com- 

 putations: Dr. R. T. Crawford; Messrs. 

 H. K. Palmer, Joel Stebbins, Ralph Curtiss, 

 C. A. 6. "Wejnnouth, Fellows in the Lick 

 Observatory; and Sliss A. M. Hobe. 



The Phofoheliograph of the U. S. Naval 

 Observatory; Its Use and Defects in 

 Solar Photography : G. H. Peters. 

 This paper dealt with the changes made 

 in the instrument during the past four 

 years. A considerable variation of focal 

 length has been found, amounting to about 

 one half inch, between the temperature of 

 summer and winter. In a proposed new 

 and larger instrument, some defects due 

 to the attached building are to be avoided. 

 The use of Jena glass No. 0.2164 com- 

 bined with No. 0.2001, with an alternative 

 of No. 0.164, is suggested for this lens, to 

 reduce the secondary spectrum to a mini- 

 mum. 



Attention was called to the necessity of 

 a study of the thermo-focal changes in long 

 focus lenses, to be used in eclipse work. 



Besults of Meridian Observations for Stel- 

 lar Parallax made at the Washburn Ob- 

 servatoi-y, University of Wisconsin: 

 Albert S. Flint. 



Results were presented for a list of 

 ninety-six stars whose distances from the 

 solar system were to be determined. This 

 list consists mainly of stars whose proper 

 motion, or di"ift across the heavens, is com- 



paratively large; and these results show 

 that, on the average, the larger this ap- 

 parent motion, the nearer the star. These 

 observations were forwarded to Professor 

 Kapteyn, of Groningen, Holland, who 

 made use of them in an important investi- 

 gation of the structure of the heavens. 



Preliminary Statement of the Magnetic 

 Disturbances Coincident with the Re- 

 cent Eruption in Martiniqtt,e : L. A. 

 Bauer. 



The disturbances of the magnetic needle 

 coincident with the volcanic eruption of 

 May 8 and 20 were felt practically simul- 

 taneously at the four Coast and Geodetic 

 Survey magnetic observatories situated 

 respectively at Cheltenham (Maryland), 

 Baldwin (Kansas), Sitka (Alaska) and 

 Honolulu (Hawaiian Islands). 



In response to a circular sent by the 

 Superintendent of the Coast and Geodetic 

 Survey records have been received from 

 the principal foreign observatories. A 

 cui'sory examination of these records shows 

 the disturbances and that they occurred 

 practically simultaneously at all of the 

 observatories thus far heard from. An ex- 

 amination of the records indicates that ap- 

 parently there were premonitory sjrmptoms 

 a month before the actual outbreak. The 

 records will be subjected to a critical dis- 

 cussion, with the view of settling definitely 

 whether the cause of these remarkable dis- 

 turbances had its source within or outside 

 of the earth's crust. 



A comparison of these effects was made 

 with that which had revealed itself during 

 the total solar eclipse of May 28, 1900, and 

 also the more recent one of May 18, 1901. 

 It was shown that the eclipse effect is not 

 in any sense to be classed as a magnetic dis- 

 turbance, but that it is of the periodic 

 variation kind and is precisely similar in 

 character to the solar diurnal variation. 



