Manchester Memoirs, Vol. Hi. (1908), No. 14. 13 



pith helmet. This is also the case in the hills, where the 

 temperature may be low enough to necessitate European 

 winter garments. In the Arabian sea cases of sunstroke 

 are reported as occurring through inadvertent exposure 

 for a very short time outside the deck awnings. In the 

 Mediterranean, however, such protection is considered 

 unnecessary, although, as already stated, the records in 

 the Mediterranean are higher than in Calcutta. 



This would lead to the conclusion, that the sunstroke 

 effect does not depend upon photo-chemical rays. 



This conclusion is further confirmed by some experi- 

 ments, facilities for which were kindly afforded by Captain 

 Llewellyn of R.M.S. "Oriental" while crossing the Arabian 

 Sea. Captain Llewellyn stated that frequent cases of 

 sunstroke occurred among crews in open boats in the 

 tropics, and the question arose whether the effect was due 

 in any measure to rays reflected from the water. In 

 order to determine whether the photo-chemical effect was 

 increased by such rays, one bottle was slung overside and 

 suspended about one foot from the water, another was 

 exposed in the usual way on a white plate, and a third on 

 the planking of the deck. The observation was taken on 

 May 8th, 1906, from 12-26 to 12-56 p.m., lat. 16-31, 

 long. 54-8. The Arabian coast was in sight, the sunshine 

 was brilliant, and the sea a bright blue. The following 

 results were obtained : — 



