'1-23 



On the succeeding day, however, the eruptions were repeated with 

 still greater violence than before ; and the quantity of matter thrown 

 up subsequent to this period was so great, that upon Capt. Tillard's 

 return to St. Michael's on the 4th of July, one side of the crater was 

 elevated nearly eighty yards above the level of the sea, and the circuit 

 of it so nearly complete, that the channel of communication between 

 the inside and outside was not more than six yards over, and the 

 water within was boiling hot. The beach was also proportionally 

 heated ; so that although by rowing round to the leeward side Capt. 

 Tillard was able to land on the outer margin, the heat prevented his 

 ascending at that part more than a few yards. The inclination also 

 was so steep on all sides, as to occasion considerable difficulty in the 

 attempt to reach the summit. The declivity below the surface of the 

 sea was such, that at the distance of twenty or thirty yards the depth 

 was found to be twenty-five fathoms. 



A portion, about sixty feet in length, on one side of the opening 

 being separated into a sort of peninsula, this part was chosen for as- 

 cending, by means of a narrow isthmus of cinders, that connected it 

 with the rest of the circumference of the crater. 



When Capt. Tillard had ascended the ridge, it was found too nar- 

 row to walk upon, the descent within being as steep as that on the 

 outside. But the ridge gradually widened toward the other extremity, 

 which was elevated between twenty and thirty feet from the sea, 

 with a flat top, bounded by a precipice on one side of the channel of 

 entrance. 



Within the crater was found the skeleton of a guard-fish, so burned 

 as to break to pieces on attempting to take it up ; and it was said 

 that great numbers of fish had been destroyed by the eruption, and 

 thrown dead upon the coast of St. Michael. 



The general material of which this mound consisted, was found 

 to be a spongy substance like cinders, to which stones had been re- 

 duced by the action of heat ; but there were also other portions of 

 stone that had undergone no such alteration. 



On the primitive Crystals of Carbonate of Lime, Bitter-Spar, and Iron- 

 Spar. By William Hyde Wollaston, M.D. Sec. R.S. Read Fe- 

 bruary 13, 1812. [Phil. Trans. 1812, p. 159.] 



In consequence of the supposed agreement of these three minerals, 

 in the same primitive form of their crystals, the two latter have been 

 arranged by the Abb6 Haxiy among those varieties of carbonate of 

 lime which contain substances foreign to its proper chemical nature. 



It has been objected to M. Haiiy, that the magnesian carbonate of 

 lime, or bitter-spar, is a proper checrical compound, and as such 

 should have a form different from that of mere carbonate of lime ; 

 and that since iron-spar frequently contains little or no lime, its 

 crystalline form should also be different. 



It is now found by the author of the present communication, that 

 such differences as the theory appeared to require do actually exist. 



