42 THE CRUISE OF THE BETSEY ; OR, 



did not know, until full four months after, that aught more 

 rare was to be found. Had we examined somewhat more 

 carefully, we might possibly have done what Mr Woronzow 

 Greig did on the Scuir about eighteen years previous, picked 

 up on it a picee of bonajtde Scotch pumice. This gentle- 

 man, well known through his exertions in statistical science, 

 and for his love of science in general, and whose tastes and 

 acquirements are not unworthy the son of Mrs Somerville, 

 has kindly informed me by letter regarding his curious dis- 

 covery. "I visited the island of Eigg," he says, "in 1825 

 or 1826, for the purpose of shooting, and remained in it se- 

 veral days ; and as there was a great scarcity of game, I 

 amused myself in my wanderings by looking about for natu- 

 ral curiosities. I knew little about Geology at the time, but, 

 collecting whatever struck my eye as uncommon, I picked up 

 from the sides of the Scuir, among various other things, a bit 

 of fossil-wood, and, nearly at the summit of the eminence, a 

 piece of pumice of a deep brownish-black colour, and very 

 porous, the pores being large and round, and the substance 

 which divided them of a uniform thickness. This last speci- 

 men I gave to Mr Lyell, who said that it could not originally 

 have belonged to Eigg, though it might possibly have been 

 washed there by the sea, a suggestion, however, with which 

 its place on the top of the Scuir seems ill to accord I may 

 add, that I have since procured a larger specimen from the 

 same place." This seems a curious fact, when we take into 

 account the identity, in their mineral components, of the 

 pumice and obsidian of the recent volcanoes ; and that pitch- 

 stone, the obsidian of the trap-rocks, is resolvable into a 

 pumice by the art of the chemist. If pumice was to be found 

 anywhere in Scotland, we might a priori expect to find it in 

 connection with by far the largest mass of pitchstone in the 

 kingdom. It is just possible, however, that Mr Greig's two 

 specimens may not date farther back, in at least their exist- 



