Atwood.] 84 [Junes, 



Dr. C. T. Jackson presented some specimens of Petrosilex 

 and Porphyry from Melrose, on behalf of Mv. Wm. B. Shedd. 

 The following analysis of the green Peti-osilex was read: — 



Silica 86.00 



0.x. Iron and Ahiniina 2.00 



Lime 1.12 



Magnesia 1.10 



Water 1.50 



Alkalies diff. 8.28 



100.00 



Captain N. E. AtAvood presented a buoy or float, made of 

 the inflated stomach of a black-fish ; it was attached to a 

 line, and used in harpooning whales. He also exhibited a 

 large drawing of a sperm whale, and oflEered some remarks 

 upon the habits of this cetacean. 



The sexes differ greatly in size; tlie males ai'e much the largest, 

 and yield fi*om fifty to one liiindred ban-els of oil, and sometimes even 

 a greater quantity ; a specimen of the lower jaw of a sperm whale. 

 in the Museum of the Society, was taken fi-om an animal that yielded 

 one hundred and forty-six barrels. The females are small, yielding 

 ordinarily from eight to twenty-five, occasionally as many as forty, 

 barrels of oil. A gi'eat proportion — on an average one-third — of the 

 oil of the sperm whale is found in the head ; the oil from this part, 

 and from the flukes, differs from that obtained from other parts of the 

 body, and was formerly considered more valuable, but since the in- 

 troduction of petroleum, both kinds are rated alike. 



From the east of the Grand Banks toward the Azores, and from 

 that line northward, the whales are mostly males, and are frequently 

 seen alone, while in the neighborhood of the West Indies, or any- 

 where within the tropics, females abound, and large schools are some- 

 times met with, composed wholly of females; at other times a few 

 males are found with them. Unlike the humpback whale, the affec- 

 tion of the cow sperm whale for its young is not very strong, for if the 

 calf is harpooned, the mother takes flight. Whalers believe that 

 sperm whales know when one of their species is harpooned, even if it 

 is miles away, for they are at once seized with a panic. 



When they go down they remain from twenty minutes to an hour. 



