£40 Mr. Alison's Narrative of an Excursion to the 



Agardh on this subject, they would not fall into absurd and 

 fantastical comparisons, which rest on the same foundation as 

 the ancient analogy detected between the moon and a green 

 cheese, on account of both being round. The learned Mr. 

 Kirby, for instance, in his " Introduction to Entomology," 

 has written in a most flattering manner of my distinction be- 

 tween relations of affinity and analogy ; but it grieves me to be 

 obliged to confess that he appears not to understand it, and 

 that his mistake principally proceeds from his forgetting the 

 necessity of parallelism between different relations of analogy. 

 If this respectable naturalist will study the works of Fries, and 

 a little work entitled De Plantarum ipr&sertim Cryptogamica- 

 rum Transitu et Analogid Commentatio" published by Theo- 

 philus Gulielmus Bischoff at Heidelberg in 1825, and will 

 then praise me, I shall be gratified by his praise ; at present 

 I must say I feel that I do not deserve it, and unmerited ap- 

 probation is a poor recompense for being made to patronize 

 or father notions that I have no wish to lay claim to. 

 [To be continued.] 



XXI. Narrative of an Excursion to the Summit of the Peak 

 ofTenerijfe on the 23rd and 24<th of February 1829. By 

 Robert Edward Alison, Esq. 



[Continued from p. 30.] 



AFTER leaving on our left a steep mountain of pumice, 

 called Montana Alta, we passed La Estancia de la Cera 

 and La Cueva de la Machoura, and entered the Canadas del 

 Pico, the thermometer standing at 50° *5. The Canadas is an 

 immense plain of white and yellow pumice, extending round 

 the Peak from W.S.W. to E. by N. forming part of an 

 ellipsis of seven or eight square leagues in extent. The sur- 

 face is 8957 feet* above the level of the sea; and rather to- 

 wards one side of this plain, in lat. 28° 17' N., and in Ion. 16° 

 39' 45" W. rises the Peak to the further elevation of 3231 feet. 

 At 10 h 30 m A.M., thermometer standing at 49°, we passed a 

 mass of porphyritic rocks called La Gayeta, and afterwards 

 some of a similar character, called by the guides La Estancia 

 de Juan Benitiz. Shortly afterwards a thick mist swept across 



* This elevation was ascertained by M. Mouneron by levelling, and after- 

 wards confirmed by Humboldt by barometrical admeasurement, calculated 

 by the formula of Laplace. Most of the elevations which I have given here 

 were very kindly furnished me by Dr. Don Domingo Savinon of Laguna, a 

 physician, who by his various scientific attainments is an honour to his pro- 

 fession. This gentleman has a collection of valuable observations respecting 

 the physical history of TenerifFe, which, it is to be hoped, he will at some 

 future period give to the world. 



US, 



