338 Potato Disease. [Dec, 



racter. Mr. Caklecott's experiments conclusively establish (as he 

 himself has pointed out), the error of the doctrine of Boussingault 

 (at least for the eastern hemisphere), that the annual temperature 

 near the equator remains unchanged at the depth of a foot below 

 the surface in the shade. This mistake it is the more important 

 to correct, because M. Poisson has attempted to confirm his 

 mathematical theories of heat by applying them to this alleged 

 fact. 



The experiments of Mr. Caldecott and Captain Newbold, as 

 indeed had those of former observers, conclusively dispose of the 

 theory of Kupfer, who imagines the "earth's temperature to be less 

 than that of the air between the tropics," and of Boussingault, 

 who supposes them to be the same. — Gardener's Chron. 



POTATO DISEASE. 



June 28 — Mr. Westwood made some remarks before the Brit- 

 ish Association, on the existence of the Potato Disease in Oxford- 

 shire. Some potatoes of his own had been attacked this year, 

 and in three different districts around Oxford he had observed its 

 presence. As an entomologist, he wished to deny inosi distinctly 

 that he thought the disease arose from the attacks of an insect. It 

 had been stated by Mr. Smee that it arose from the attacks of a 

 new aphis, which he called vastator, but this aphis, far from be- 

 ing new, had been described many years ago, and was a very 

 common insect on decaying plants. Another gentleman propos- 

 ed to call the insect A. pestilens. Mr. Westwood drew attention 

 to the ignorance such observers displayed, as rendering it neces- 

 sary that zoology should be taught as a branch of education. He 

 was sorry to be speaking on this subject in an English Universi- 

 ty where neither zoology nor comparative anatomy we recognis- 

 ed as necessary to complete the education of the professional man 

 or gentleman. Mr. J. E. Gray stated that he had compared 

 some specimens of the aphis vastator with species of aphides in 

 the liritish Museum, and found that under this name Mr. Smee 

 had included thiee or four well known species. Dr. Lankester, 

 drew attention to a bundle of potato stalks which he had brought 

 from Pangbourne which gave every sign of disease, but not an 

 aphis could be found among them. One fact of this kind was 

 sufficient to prove that the disease had no dependance upon the 

 insect. He had heard from a gentleman in Mancliester that po- 

 tatoes sown in new soil on Chat Moss were free iiom the disease, 

 whilst those sown in old soil all had the disease. This looked as if 



