423 



tree, like picea, resembling the Dammara pine of New Zealand 

 and the Feejee Islands. The coal exhibited may be the product 

 of the resin of this pine, and, if so, might with advantage be 

 compared with the New Zealand gum-copal, which differs somewhat 

 from resin. He did not think the impressions bore any resem- 

 blance to those which would be made by roots. 



Dr. Jackson also exhibited specimens of coal from the 

 Gulf of Chiriqui, between Costa Rica and Panama, dis- 

 covered by Dr. John Evans. 



It contains about forty per cent, of bituminous matter, with 

 nine per cent, of ash ; it is well adapted for steam engines, for the 

 manufacture of gas, and for similar purposes, and, if existing in 

 large quantity, will be of immense value to this region. Judging 

 from the fossils which accompanied the specimens, such as Car- 

 dium, Cerithium, Area, Natica, Mytilus, and other shells, this coal 

 belongs to the upper Eocene period. 



Mr. Marcou observed that all coal hitherto found within the 

 tropics has been Tertiary, and does not belong to the true coal meas- 

 ures ; the latter have always been formed and found either in 

 arctic or temperate zones, in swampy regions ; during the true 

 Carboniferous deposits the terra firma was found under the tropics. 



Dr. C. T. Jackson exhibited a microscope recently- 

 made for him by R. B. Tolles, of Canastota, N. Y. 



This is the inverted microscope of Prof. J. Lawrence Smith, 

 described by him in the American Journal of Science and Arts, 

 vol. xiv. p. 233, 1852. It is peculiarly adapted for the use of 

 the chemist, the object to be examined being placed above the 

 objective lens, while the tube is inclined at an angle of 45 '^. 



Mr. Verrill exhibited some specimens of minerals. 



The first was a piece of tin ore, from Mt. Mica, Paris, Me., 

 and was part of a mass which weighed five pounds ; he had also 

 found several smaller specimens, some beautifully crystallized, 

 scattered through the mass of rock constituting the vein ; they 

 were generally in contact with albite or quartz. 



A second specimen he supposed to be native arsenic, though it 



