December 29, 192 1] 



NATURE 



561 



The economic difficulty of providing efficient 

 apparatus in place of the jerry-built stoves, 

 ignorantly designed with a view to cheapness of 

 primary cost and superficial appearance, impels 

 the poor to be chief offenders and sufferers through 

 no fault of their own, while the rich man can 

 afford to buy, and has space to fix, economical 

 fittings. He also, as Mr. Barker says, has the 

 intelligence, or can purchase it, to use these pro- 

 perly and prevent the even greater waste of fuel 

 which results from the careless or ignorant use 

 of such fittings. Thus the nation's wealth of coal, 

 which should be conserved or used for export and 

 barter, is wasted, and the sky is fouled with 

 smoke, cities and persons are made unclean, build- 

 ings corroded, decorations, furniture, and clothing 

 spoilt, a vast amount of human energy wasted in 

 cleaning, painting, etc., the transit of goods and 

 people is impeded by fog, with consequent very 

 great economic loss, energy wasted in needless 

 artificial illumination, vegetation stunted or 

 destroyed, and people in cities are thus 

 deprived of green food, salads, etc., which 

 might be grown in back gardens and allot- 

 ments — foods, by the way. which are the 

 great natural store of the essential growth 

 and health principles : the vitamins. Owing to 

 the smoke pall, people are impelled also by the 

 gloom of their surroundings from outdoor exer- 

 cise to indoor pursuits, with conseqijent deteriora- 

 tion of health and stamina. A life spent in stag- 

 nant air within doors, with its low cooling and 

 evaporative power, depresses the body heat pro- 

 duction, lessens appetite, makes the breathing 

 shallow, enfeebles the circulation, leads to de- 

 rangements of the bowels and constipation, to loss 

 of muscular tone and vigour, and makes pale, 

 weakly, and unhappy citizens. 



The reviewer is writing these sentences in 

 November at Montana-sur-Sierre in Switzerland at 

 an altitude of 5000 ft. where the sun is shining 

 5ome eight hours a day, although it is freezing in 

 the shade, and the air is almost calm and ver}- 

 dry. While the surface temperature of his coat is, 

 in the sun, 40-50° C, the cooling and evapjorative 

 power of the air exerted on the skin is high ; so, 

 too, on the respiratory membrane. On the surface 

 of the dry kata-thermometer at body temperature 

 the cooling power averages 15—20 millicalories per 

 sq. cm. per sec, while the evaporative power, 

 measured by the difference between the drv and 

 wet kata-thermometer, averages about 20 milli- 

 calories per sq. cm. per sec. ; the surface tem- 

 perature of the cheek exposed to such conditions 

 is about 25° C. To these conditions children with 

 tubercular disease of the joints or spine are ex- 

 NO. 2722, VOL. 108] 



posed, splinted and nude, on their beds, and, 

 bathed by sun and cool, dry air, do wonderfully 

 well. Their body heat production is sent up some 

 100 per cent, above that of children clothed and 

 resting in a chamber. On the other hand the 

 cooling power in ordinary rooms and workshops in 

 England, called fresh, is 5-6, as measured by the 

 dry kata-thermometer, the evaporative power 

 10-12, and the cheek temperature about 33° C. 

 There is in such rooms, heated by hot water or 

 steam coil, no source of radiant energy to warm 

 the surface of the clothes as the sun at Montana 

 warms these to 40-50° C. ; it is the sun which 

 makes comfortable the high cooling and stimulat- 

 ing power of the Alpine air. 



Children become consumptive and rickety in 

 tenement dwellings through the want of vitamins 

 and other essential food principles and the con- 

 finement which depresses their metabolism. They 

 are then sent to be cured at expensive sanatoria 

 bv open-air treatment and good food. How waste- 

 ful it is for a Government to let them become 

 diseased, how absurd to educate the still healthy 

 young in confined school-rooms, when open-air 

 treatment is proved to restore the unhealthy to 

 good health. By coal conservation and the use 

 of smokeless fuel, gas, etc., not only can the 

 skies be cleaned and our proper share of sunshine 

 obtained, but green foods can be grown and eaten 

 and open-air exercise taken by many more than 

 at present. Such a reform, together with the 

 extension of smokeless factory garden cities, are 

 the great aims of preventive medicine ; such 

 measures, together with wise control of breeding, 

 may prevent, or at any rate delay, the nation be- 

 coming worn out as past empires, as communi- 

 ties of ants in ant-hills, become worn out by over- 

 crowding. 



Mr. Barker's book will be of use to all those 

 who wish to choose heating and lighting appli- 

 ances and run these with economy. He points out 

 that to use electricity generated from coal for 

 heating and cooking is unjustifiable when the 

 saving of money and fuel are paramount con- 

 siderations, for only some 8 per cent, of the 

 thermal energ\' of the coal is converted into elec- 

 tricitv at the power stations, and the rest is 

 wasted. Electricity generated from water-power 

 otherwise running to waste is, on the other hand, 

 the most convenient and economical source of 

 heat. 



" Hot water can be supplied by burning solid 

 fuel in a suitable apparatus very economic- 

 ally." " One ton of fuel used in an ordinary range 

 will supply as much hot water as 20,000 cubic feet 

 of gas in an ordinary gas boiler at about two- 



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