The Royal Observatory of Scotland. 55 



would be so great, as to leave far behind all attempts to 

 observe the same objects on the surface of the earth with 

 instruments of equal calibre. 



" To give a first idea of the practical details, I may mention 

 that the mountain which I propose is the Peak of Teneriffe ; 

 of all high mountains the most quickly accessible from 

 England, the most easily climbed, and having the very con- 

 siderable elevation of 12,500 feet. Its whole distance from 

 England lies almost due south, most effective therefore for 

 taking one, during the summer, into the darkness of tro- 

 pical nights ; and for raising the zodiacal region of the sky, 

 always so low at home, high towards the zenith. It is more- 

 over in the direct line of the Cape steamers, hardly more 

 than a week's voyage; and from the landing-place in the 

 harbour, there is one continued slope to the top of the moun- 

 tain ; instead of the usual long winding and undulating 

 ascents and descents which must generally be overcome, be- 

 fore any very lofty station can be gained in most other parts 

 of the world. Abundance of labourers and mules appear to be 

 procurable ; a sufficiently large plateau for the necessary 

 erections exists at the height of 12,000 feet, and is stated to 

 be clear of cloud throughout the summer ; while, if one ob- 

 servation of Humboldt's can be depended on, the air is there 

 more transparent than at the same height on either the 

 Alps or the Andes. Moreover, as to the instrument itself, I 

 have devised a new construction of the equatorial stand 

 which will allow of its being taken to pieces, and transported 

 with great facility : and all the observations, when made, 

 being brought home each autumn, the computation and the 

 printing thereof would be managed without difficulty, as a 

 part of the usual Observatory volume, the permanent astro- 

 nomical value of which would be thereby very greatly in- 

 creased." 



