96 CARNEGIE INSTITUTION 



tain general problems in astronomy. In a later portion of this 

 Appendix we have treated this subject more fully, and we would 

 respectfully invite the attention of the Trustees to the considerations 

 and recommendations which we have presented under this head. 



An Observing Station for Solar Research. 



In a communication which Professor Langley, in response to a re- 

 quest from the Secretary of the Institution, has addressed to the 

 Committee and which we have incorporated in this Appendix, at 

 the end, he has drawn attention to the need which novt' exists for 

 research upon solar radiation and its possible variations. We are 

 in accord with Profes.sor Langley in believing that a great advance 

 in our knowledge of the physics of the Sun may be anticipated from 

 a research of at least eleven years' duration with special and power- 

 ful apparatus, located at mountain stations, presumably in a sub- 

 tropical region, substantially as he has presented the subject. He 

 estimates that the entire cost of the undertaking would be about 

 $500,000, and the detailed estimates which he has presented seem to 

 warrant that view. The Sun, as the source of those energies which 

 govern the kinetic and vital conditions of the several planets, pos- 

 sesses an unusual interest for mankind. As the only star whose 

 physical condition can be investigated in detail, it offers almost the 

 only opportunity we have for finding the key to the interpretation 

 of problems concerning the evolution and present condition of stars 

 presented through the evidence of the spectroscope. 



As v/ill be seen, Professor Langley, in his communication, is im- 

 pressed with the utilitarian advantage which might possibly grow 

 out of this research. He thinks it possible that by means of this 

 study we may hereafter be able to predict climatic changes of great 

 importance to the welfare of mankind. 



We think that the scheme outlined by Professor Langley is 

 worthy of close attention and detailed examination on the part of 

 the Institution. 



Development of a Large Reflector. 



The remarkable development of the reflecting telescope in recent 

 years opens up a large field of possible accomplishment through the 

 use of powerful reflectors. The photographs of nebulae which were 

 made with the Crossley three-foot reflector at the Lick Observatory 



