162 TRANSACTIONS OF THE ACADEMY. 



ture, barometrical pressure and direction of the wind, being 

 noted. The consideration and further examination of the 

 subject was referred to section first. Professor Ducatel, also 

 presented a memoir on a system of meteorological observa- 

 tions, prepared by Mr. Nicollet, and submitted by him to the 

 secretary of war, being the basis of the observations now 

 being made at the different military and naval stations of the 

 United States, by order of the government. 



February 26. — Donations for the library, were received from 

 Mr. Alexander and Dr. Geddings. From the former a copy of 

 'L'Histoire des Oiseaux d'Afrique,' by Levaillant, two vols, 

 folio ; from the latter, copies of 'Lehmann's Jungermania,' 

 'Baltimore Medical and Surgical Journal,' and 'North Ameri- 

 can Archives.' Mr, W. R. Fisher, read a short memoir on 

 'Amalgams for electrical machines,' and exhibited specimens 

 of mosaic gold, and Baron Keinmayer's mercurial amalgam, 

 prepared by the processes described in the paper ; all referred 

 to section first. Mr. Green exhibited some electro-magnetic 

 phenomena, and accompanied the experiments with an account 

 of the fact first observed by Mr. Ritchie, that the length of 

 time during which an electro-magnet retains its armature, after 

 the connection is destroyed, depends upon the length of its 

 arms. A donation was received from Dr. Geddings, of a 

 collection of southern plants; referred to section 5th. 



March 3. — Donations of various books for the library were 

 received from Professor Ducatel and Mr. Alexander ; a dia- 

 gram of the human eye from Mr. Green ; a map showing the 

 connection of the Baltimore and Ohio rail roads, with other 

 rail roads projected and completed, from Mr. Fisher. Speci- 

 mens were received for the cabinet from Mr. I. Tyson, Jr. 

 chrome ore, in a matrice, said to be feldspar ; from Mr. P. T. 

 Tyson, a large specimen of asbestos, variety amianthus, 

 obtained at the intersection of the Susquehannah rail road with 

 the Gunpowder river; from Mrs. E. Geddings, a collection of 

 southern plants. Dr. T. Edmondson, Jr. reported a meteoro- 

 logical table for February, 1836— referred to the section of 

 physics, <fec. A list of minerals was submitted by Professor 

 Ducatel, at the request of the consul-general of France, which 

 the government of that country is desirous to obtain — referred 

 to the section of mineralogy. Don Ramon della Sagra, of 



