950 



SCIENCE. 



[N. S. Vol. XIV. No. 364. 



Still is) criticised by outside astronomers. 

 Malice has dictated these criticismSj to my 

 knowledge, for thirty years. In this in- 

 stance ignorance becomes a valuable acces- 

 sory. 



THE 40-FOOT PHOTO-HELIOGRAPH. 



Photographs have been taken of the sun 

 daily whenever the weather and other cir- 

 cumstances would permit. During the 

 absence of the photographer, Mr. George 

 H. Peters, on duty with the eclipse expedi- 

 tion, his place was supplied by Mr. E. A. 

 Boeger. computer. 



THE TOTAL SOLAR ECLIPSE OF MAY 18, 1901. 



By virtue of a provision of the urgency 

 deficiency bill of the last session of Con- 

 gress, the Observatory was enabled to equip 

 and put in the field an expedition to the 

 island of Sumatra to observe the total 

 eclipse of the sun of May 18, under charge 

 of Professor A. N. Skinner, U. S. IST. Pro- 

 fessor Skinner's very interesting prelim- 

 inary report of the expedition and its re- 

 sults is forwarded herewith. A detailed 

 report will appear in conjunction with a 

 report of the eclipse of May 28, 1900, in a 

 forthcoming volume. 



It may very reasonably be asked whether, 

 in view of the meager results on account of 

 cloudy weather on the day of the eclipse, 

 the expense of sending an expedition to such 

 a distance was a justifiable outlay of public 

 money. The reply would be that a chance 

 of failure on account of the weather was one 

 of the conditions which attached unavoid- 

 ably to the undertaking. Other expedi- 

 tions were less fortunate and secured no re- 

 sults at all. But the real answer is that 

 results, no matter how meager, fully justify 

 the outlay, because such results are not to 

 be judged by themselves, but are to be re- 

 garded as forming a part of the general sum 

 of observations of this and other eclipses. 

 The problems presented will be solved, not 

 by the recorded observations of any one 



person at any one time, but by the accumu- 

 lation of such observations in the general 

 account of human knowledge. From this 

 point of view even one photograph, or a 

 single observation of contact, would have 

 fully justified the entire outlay. At Fort 

 de Kock ten excellent negatives were ob- 

 tained, which were acknowledged by foreign 

 astronomers to be the best made by any 

 party in the field, and at Solok, the Observa- 

 tory's other station, contacts were observed 

 and some photographs obtained. I am 

 satisfied with the results. 



A serious drawback to the expedition has 

 been the withdrawal for so long a period of 

 an important part of the Observatory's as- 

 tronomical staff. 



An acknowledgement is due the War 

 Department for uniform courtesy to the 

 expedition both on board the transports 

 and at Manila, and to the commanding 

 officer of the U. S. S. General Alava for 

 much valuable assistance. 



COMPUTATIONS AND PUBLICATIONS. 



Since my last report the whole computing 

 force of the Observatory has been assembled 

 in one division, instead of being distributed 

 to the various instruments as heretofore. 

 This change has resulted in a decided econ- 

 omy of time and labor, and is generally in 

 the interests of system and efficiency. All 

 astronomical observations, by whomsoever 

 made, are turned over to the computing 

 division for reduction, it being understood 

 that the author is consulted as to the meth- 

 ods of reduction and exercises a general 

 supervision in cooperation with the officers 

 at the head of the division. Professor 

 Eichelberger has been placed in charge of 

 this division, and in his absence with the 

 Sumatra eclipse expedition his place was 

 supplied by Assistant Astronomer King, up 

 to the close of the fiscal year. 



During the year the first volume of the 

 new series of Washington Observations has 



