218 



Scientific Intelligence, 



[March, 



minerals by Mr. Allan, in our last number. We think a few 

 more facts respecting him will be interesting to our reader? He 

 lias long been well known on the Continent as a dealer in 

 minerals, adding to unbounded zeal a great knowledge of 

 mineralogy. In the year 1806 he left Copenhagen, in a Danish 

 ship, for Greenland, with the intention of collecting the valuable 

 and rare minerals which occur in that remote region. While he 

 was absent his valuable mineralogical collection in Copenhagen 

 fell a sacrifice to the flames during the bombardment of that 

 capital by the English. To add to his misfortunes, a considerable 

 collection of the rarest minerals in Greenland, which he had 

 shipped on board a Danish vessel for Copenhagen, was taken by 

 a British croizer. This is the collection described by Mr. Allan, 

 in the second number of this Journal, and containing, as our 

 readers will perceive, on the slighttst inspection, several of the 

 most curious minerals hitlierto discovered. When Gieseke was 

 informed of these disasters, he resolved, although struggling wuh 

 want, to prolong his stay in that country, in order to replace the 

 rich collection which he had lost. 



VI . SarcocoL 



It has been generally believed that the substance called 

 sarcoeol is an exudation from tlie pen6P.a sarcocolla ; but there is 

 very good reason to doubt the truih of the opinion. It was first 

 laken up by Linnffius, and has been maintained ever since upon 

 - the authority of his name. Professor Thunberg has published 

 an account of the genus penj*a in the Gesellschaft Naiurfar^ 

 schencler freunde zu Berlin Magazin for I8O7, p. 121. The 

 species are ten. They all grow at the Cape of Good Hope, and 

 have been seen nowhere else. The peneea sarcocolla grows on 

 the mountains of Hottentot Holland, and in those below the 

 west side of the Table Mountain. Now Thunberg, who was on 

 the spot, expressly affirms that sarcoeol is neither collected nor 

 known in that country. 



It would have some tendency to throw light upon the plants 

 that yield several resins, and gum resins, with the history of 

 which we are at present unacquainted, if any wholesale druggist, 

 or merchant, in London, who is in the habit of importing these ^ 

 articles, would state the countries from which they are brought. 



¥11. 'Marine Transit. 



la reading over the description of the marine transit published 

 in a late number of the Philosophical Magazine (Vol. xl. p. 

 401), there was a circumstance which struck me as likely to be 

 of considerable importance. I do not know whether Mr. 

 Clievasse has adverted to it, but at all events it can do no harm 

 to draw his attention to it. When mercury is agitated in contact 



