^g Scientific Intelligence. [Jan, 



I find Is an aggregate of three different minerals ; namely, felspar, 

 quarlZf and garnet. The felspar and quartz are both white, and 

 constitute the greatest part of the rock. The garnet is scattered 

 through the rock in small red grains and crystals. From this 

 specimen it appears that our notions respecting this rock in this 

 country have been hitherto incorrect. I have never seen any rock 

 resembling it in Great Britain, except in cabinets ; and in no one 

 case was I able to learn whence the specimen had come. We see 

 too that Klaphroth's analysis, given in a preceding number of the 

 Annals, is of no real utility, as the constituents so found must 

 depend upon the accidental proportions of the three minerals con- 

 stituting whitestone. 



X. Height of the Peak of Teneriffe. 

 Of all the measurements of this mountain, there seem to be 

 only three upon wliich v/e can rely. Borda measured it trigono- 

 metrically in 177^5 Lemanon barometrically in 17^5; andCordier 

 barometrically in 1803. Their results are as follows : — 



Borda 1905 French toises. 



Lanianon 1902 



Cordier 1920 



Mean 1909 



This gives us the height of the peak above the level of the sea, 

 12,207 English feet. 



XI. Dip of the Magnetic Needle, and Intensity of the Magnetic 

 Forces in the North Atlantic in 1799. 



Humboldt's Personal Narrative, ii. 115. 



XII. Postman of the Province of Jaen de Bracamoros. 



In order to render the communication between the coasts of the 

 Pacific Ocean, and the province of Jaen de Bracamoros, situated 

 on the cast of the Andes, more easy, the postman of Peru 



