19 [ 1 ] 



A series of experiments has also been made, for tcstinp^ the perform- 

 ance of the Aneroid barometer under extremes of atmospheric pressure. 

 The instrument as usually constructed, has not been found, from these 

 experiments, very reliable, though it may be improved, and thus serve as an 

 indicator of mimite atmospheric changes. I think, however, it will not 

 answer for the determination of changes of atmospheric pressure, of con- 

 siderable magnitude. 



For the better comprehension of the relative position of the several 



. places of observation, now embraced in our system of meteorology, an 

 outline map of North America has been constructed, by Prof. Foreman. 

 This map is intended also to be used for presenting the successive phases 

 of the sky over the whole country, at difi'erent points of time, as far as 

 reported to us, and we have been waiting for its completion, to commence 

 a series of investigations, with the materials now on hand, relative to the 

 progress of storms. 



A valuable collection of returns relative to the Aurora, has been re- 



: ceived in accordance with the special instructions which we have issued 

 for the observation of this interesting phenomenon. These are to be 

 {)laced in the hands of Captain Lefroy, of the Toronto observatory, and 

 incorporated with observations of a similar kind, which he has collected 

 in the British possessions of North America. An account in full of the 



, whole series will be presented by Captaiji Lefroy, to be published in the 

 Smithsonian Contributions. 



The meteorological correspondence is under the charge of Professor 

 Foreman. This is found not (*nly to ijivolve considerable labor -in the 

 way of receiving the regular returns and sending the required blanks and 

 directions, but also in relation to the discussion of questions on almost 

 <*very branch of science propounded to us by the meteorological obser- 

 vers, which w^e think it our duty in all cases, to treat with respect, and to 

 .answer to the best of our knowledge. 



RESEARCHES, &C. 



Explorations. — The programme of organization contemplates the insti- 

 tution of researches in Natural History, Geology, &c., and, though the 

 state of the funds would permit of little being done in this line, yet we 

 have made a beginning. Besides the assistance rendered to the explora- 

 tion of the botany of New Mexico, by the purchase of sets of plants from 

 Mr. Wright and Mr. Feiuller, as mentioned in my last report, a small sum 

 was ap{)ropriated, to defray the cost of transportation of the articles which 

 might be collected by Mr. Thaddeus Culbertson, in the region of the 

 Upper Missouri. This gentleman, a graduate of the institutions at Prince- 

 ton, had purposed to visit the remote regions above mentioned, for the 

 benefit of his health, and was provided by Professor Baird, with minute 

 directions as to the preservation of specimens and the objects which should 

 particularly engage his attention. His journey w^as undertaken, and 

 rsecuted, under jjarticularly favorable circumstances for exploration. Jle 

 was accompanied by his brother, Mr, Alexander Culbertson, for many 

 years connected with the American Fur Company, who was familiar with 

 the whole country, and had himself sent valuable specimens of fossil 

 mammalians to the Philadelphia Academy of Natural Sciences. 



Mr. Culbertson first visited an interesting locality called the Mauvaises 



