155 



not exceed two hundred and fifty dollars. The value of the results 

 would be much increased, by providing a self-registering anemometer 

 and rain-gauge, instead of the common ones, which would increase 

 the cost of each set of instruments to five hundred and seventy dol- 

 lars. The whole cost of erecting the five observatories, and providing 

 them with excellent instruments, will pi-obably not exceed sixteen 

 thousand dollars ; and if the observatory already existing at Philadel- 

 phia, and provided with the necessary instruments, should be adopted 

 as one of the five, and four others be erected and furnished, the 

 expense to the United States would not exceed twelve thousand 

 dollars. 



No estimate is made of the cost of the principal and assistants for 

 the proposed observatories. In the organization of the new British 

 stationary observatories, these persons are taken, in part, if not alto- 

 gether, from the officers, non-commissioned officers, and privates of 

 the artillery. The acquirements of the graduates of our Military 

 Academy, admirably fit them for directing the observatories, which 

 might be appropriately placed at military posts ; so as to provide the 

 officers and men necessary for making the observations, without addi- 

 tional expense. The direction thus given to the views of the Com- 

 mittee ; the fact that you have long been enrolled as a member of the 

 American Philosophical Society; and the interest which you have 

 always manifested, both as an individual and in a public capacity, in 

 all enterprises calculated to shed a lustre upon your country, have 

 induced the Society to direct us to address ourselves particularly to 

 you on this subject. 



With the hope that your views may coincide with those of the So- 

 ciety, in regard to the plan now presented for your consideration, 

 we are, 



Very respectfully, yours, 



A. D. Bache, *] 



R. M. Patterson, | 



Joseph Henry, )■ Committee. 



J. K. Kane, | 



JOS. G. TOTTEN, J 



Dr. Patterson laid before the Society a specimen of the 

 Daguerreotype, by Mr. Robert Cornelius, of Philadelphia. 



Dr. Hays communicated a case of perverted vision, in which 

 all perpendicular lines appeared double, while horizontal ones 



