WORK UNDER PRESSURE AND IN GREAT HEAT 397 



Again, the well-intentioned regulation hitherto in force 

 in the British, German, and other navies, that a diver should 

 always descend very slowly, has probably cost many a diver 

 his life. 



To turn to the mining industry, one finds that often no 

 expense is spared, and burdensome regulations may be imposed 

 by law, in the endeavour to cure by unsuitable means evils for 

 which a little real investigation would have shown an effective 

 cure. In the Cornish mines, for instance, more ventilation was 

 being provided as a remedy for the evils caused actually 

 by stone dust and ankylostomiasis. The increased ventilation 

 was apparently only aggravating the evil by making the 

 working places drier and more dusty, just as in coal mines 

 increased ventilation has, by itself, often increased the danger 

 of colliery explosions by making the coal dust drier. Courrieres 

 Colliery, where 1,100 men were killed by a coal-dust explosion 

 last year, was probably one of the best-ventilated mines in 

 Europe. 



As regards heat and moisture in the air, we have in England 

 the curious anomaly in our Factory Act that the wet-bulb 

 temperature in cotton factories, where women are employed 

 all day, is expressly permitted by law to rise to even 37 , 

 provided that the proportion of C0 2 does not exceed 9 volumes 

 per 10,000 ! I do not for a moment mean to imply that any 

 manufacturer would permit such a state of matters to exist 

 in his factory, or that the workers would stay for an hour in 

 such an impossible atmosphere ; but the extemely well-meant 

 English regulations as to temperature and humidity in the 

 air of factories furnish one instance out of many, illustrating 

 the need for more knowledge and investigation. 



Such knowledge must be gained to a large extent on the 

 spot, and not merely in a laboratory. Men who are tied to 

 their work in a laboratory are often called upon to express 

 opinions about matters of industrial hygiene without having 

 any adequate opportunity of personally investigating the actual 

 conditions. It is almost invariably the case, however, that 

 investigations on the spot are essential, and that discussion 

 with engineers, managers, and workmen throws entirely new 

 light on the subject-matter. For one thing, the engineers 

 and managers help us, beyond everything, to think of things 

 quantitively and in their relations to other things. This lesson 



26 



