Natural History, fyc. 419 



light on this American formation, and his observations will derive 

 some additional interest from those which we have made in this place. 

 We possess pepitas of platinum, of many inches in length, in which 

 M. Hose has discovered beautiful groups of crystals of the metal. 



* As to the greenstone porphyry of Laya, in which M. Engelhardt 

 has observed little grains of platinum, we have examined it on the 

 spot with much care, but the only metallic grains which we have been 

 able to detect in the rocks of Laya, and in the greenstone of Mount 

 Belayr-Gora, have appeared to M. Rose to be sulphuret of iron ; this 

 phenomenon will be a subject for new research. The work of M. 

 Engelhardt on the Ural seemed to us to be worthy of much praise. 

 Osmium and iridium have also a particular locality, not amongst the 

 rich platiniferous alluvia of Nijnei'-Tagilsk, but near Belemboyevski 

 and Kichtem. I insist upon the geognostical characters drawn from 

 the metals which accompany the grains of platinum at Choco, 

 Brazil, and in the Ural.'* 



5, PARROT'S EXPEDITION TO ARARAT. 



A scientific expedition set out from Dorpat some time since, under 

 the direction of Dr. Parrot, charged with the examination of the 

 country around Mount Ararat. After many fruitless attempts, Dr. 

 Parrot arrived at the summit of Ararat, and measured the height of 

 this celebrated mountain. He found it to be 16,200 feet in elevation, 

 which makes it 1500 feet higher than Mont Blanc. Dr. Parrot 

 caused a barometric levelling to be taken by M. Behaghel, one of his 

 companions, of the whole route from Tiflis to Ararat, as well as of 

 that which leads from this city, by Imerethi and Mingrelia, to the 

 Kalch redoubt on the banks of the Black Sea ; but his observations 

 are not yet calculated. This traveller describes the western summit, 

 which is the most elevated part of Ararat, as being a plain of about 

 150 paces in circumference; eastwards it communicates by a low 



Elateau with the other summit, which is not so high; at about 1200 

 set of elevation everything is covered with ice and snow. The in- 

 struments which Dr. Parrot had with him, consisted of a pendulum 

 apparatus, a magnetic inclinatorium of ten inches, barometers, a sur- 

 veying apparatus, &c. In point of astronomical instruments, the 

 expedition was provided with a Reichenbach's theodolite of eight 

 inches, an Arnold's chronometer and one of Maynie's, a Dollond 

 telescope of three feet, and a Trongleton's sextant. 



Dr. Parrot was accompanied, as we before mentioned, by MM. 

 Behaghel, a mineralogist, Schiemann, a zoologist, and Hehn, a bo- 

 tanist all three students in the university of Dorpat f. 



6. CUTICULAR PORES OF PLANTS. 



It is well known to botanists that the cuticle of most plants is 

 furnished, especially on the leaves, with minute organs, the func- 



* Edin. Geog. Journ, ii. 441. f Ibid. iii. 38. 



