tknttjtc Jtotts 



FOR GENERAL READERS. 



Vol. II. 



NOVEMBER 30, 1888. 



No. 22. 



CONTENTS. 



PAGE 



Scientific Table Talk 545 



Roman Remains at Llantwit Major 



(Illus.) 546 



The Grinnell Fire Extinguisher (I/lns.) 548 



Cabbages 550 



General Notes 551 



The Magic Chain (///us.) 553 



The Venom of Serpents, its Nature and 



Action 553 



Natural History — 



The Albatross {///as.) 555 



British Wild White Cattle ... 

 Breeding Canary Birds 

 Miscellaneous Notes 

 The Bandai-san Eiuption ... 



Reviews — 



Handbook of Sydney 

 Essay on Cramming... 



Abstracts of Papers, Lectures, etc. 

 Royal Society 

 Leeds Geological Association 



PAGE 





PAGE 



556 



Glasgow Natural History 



Society ... 562 



'57 



Bournemouth Society c 



f Natural 



557 



Science 



562 



557 









Flints 



503 



559 

 559 



Recent Inventions 



567 



Announcements 



568 





Sales and Exchanges ... 



568 



560 



Diary for Next Week ... 



56S 



56i 



Meteorological Returns 



568 



SCIENTIFIC TABLE TALK. 



By W. Mattieu Williams, F.R.A.S., F.C.S. 



On page 486 of the current volume of this magazine is 

 a review of the proceedings of the Royal Society of 

 Edinburgh, concluding as follows : " Prof. R. Wallace 

 communicates a memoir on the ' Colour of the Skin of 

 Men and (Lower) Animals in India.' The author notes 

 that in India cattle, sheep, pigs, buffaloes, and horses, 

 whatever the colour of their hair, have black skins, and 

 of this fact he seeks an explanation." 



An explanation was offered by Surgeon-Major Alcock, 

 in apaper published in Nature, August 21st, 18S4, which 

 has not received the attention that I think it deserves. 

 The title of the paper is, " Why Tropical Man is Black." 



After enumerating some of the theories that have been 

 expounded by physiologists in struggling with this 

 problem, he states his own, which summarily expressed 

 is " that the black skin of the negro is but the smoked 

 glass through which alone his wide-spread sentient 

 nerve-endings could be enabled to regard the sun." 



The well-established law that surfaces of given 

 material exposed to the solar rays become heated in 

 proportion to their darkness of tint has rendered the 

 colour of the negro an apparent physical paradox. The 

 demand for coolness under tropical sunshine should give 

 such advantage to the white man that under conditions 

 of primitive nakedness he would have there survived 

 as the fittest for such conditions. 



This conclusion, however, is based on reasoning that 

 only includes one of the factors of the problem, viz., the 

 heat of the solar rays. The experience of shampooers 

 and other attendants in Turkish baths shows that men 

 may be continually exposed to higher temperatures than 

 those prevailing in tropical countries without suffering 

 any injury to health, or even any inconvenience. Many 

 of our English workmen do heavy work in temperatures 

 exceeding that of the Sahara. During the hot summer 

 of 1868 I was engaged in making experiments in the 

 reheating and other furnaces at Sir John Brown and Co.'s 

 works, Sheffield, and carried a thermometer, which I 

 suspended in various places where the men were work- 

 ing. Where I was chiefly engaged it stood at 120 degs. 

 with the furnace-doors shut. The men were exposed to 

 much higher temperatures from radiant heat when 



charging and withdrawing the great armour-plate piles — 

 over 200 degs. At enamelling works and at glass works 

 the temperature is still higher ; 145 degs. is a common 

 temperature in the stoke-holes of steam-packets in 

 the Red Sea. Such work is, of course, exhausting, 

 but not injurious ; such temperatures are enjoyable 

 when no muscular efforts and no clothing are 

 demanded, as in a Turkish bath. 



On the other hand, at the Creusot Steel Works, 

 where an electric furnace is used which gives out 

 a light of 100,000 candles, the men who are exposed 

 to the glare at a distance of ten or twelve yards 

 suffer severely, though the heat is but nominal. 

 They have to work with great caution and inter- 

 mittently. Nevertheless, after such intermittent ex- 

 posure of one or two hours, the effect is " a painful 

 sensation in the throat, face, and temples, while the skin 

 assumes a copper-red hue." The British Medical Journal, 

 from which I quote this, describes other symptoms, in- 

 cluding a discharge of tears, in spite of using coloured 

 spectacles, which is " very copious for twenty-four hours. 

 Simultaneously headache and sleeplessness are ex- 

 perienced, which are caused partly by the copious dis- 

 charge of tears and partly by pain and the feverish state 

 of the body. Finally, during the next few days the skin 

 of the face begins to peel off." These and the irritation 

 of the pupil of the eye, lasting for forty-eight hours, 

 followed by " a very painful sensation, as if some 

 foreign substance were introduced under the eyelids," 

 are symptoms quite familiar to myself and others who 

 have exposed themselves to the glaring light reflected 

 from mountain snow in summer-time. I have suffered a 

 complete peeling off of all the skin of face and ears, i.e., 

 of all the skin exposed to the snow-glare. 



What, then, would be the condition of the Creusot 

 workmen or the Alp climbers if the whole surface of 

 skin were exposed ? 



The seat of all this irritation is obviously not in the 

 cuticle, which is merely a protective covering of the body, 

 as insensible as the hair and finger-nails. But imme- 

 diately beneath it is the cutis vera, the true skin, a mem- 

 brane involving so close and intricate a tissue of nerves 

 and blood-vessels that we cannot insert a needle-point 

 without doing violence to a nerve-ending and rupturing 

 a blood-vessel, i.e., without pain and bleeding. 



