On the relations of some occupations to eyesight / by Simeon Snell.

  • Snell, Simeon, 1851-1909.
Date:
1894
Catalogue details

Licence: Public Domain Mark

Credit: On the relations of some occupations to eyesight / by Simeon Snell. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    ordinary well-lighted fire in a grate is about 500°F. Now, I am told there is a very marked difference in the way a temperature is borne when it is below 2,ooo°F., and when above it. Up to that figure a man can look at the metal in a furnace with comparative ease, but before it gets to 3,ooo°F. he is compelled to wear coloured glasses when doing so. My friend, Mr. VV. H. Ellis, of the Atlas Works, has kindly given mc the following data as to the heat of the metal. In dealing with cast iron the heat of the metal would be about i,8oo'' to 2,000, and the men employed take no precau- tions. The heat of the molten steel would be about 2,700° to 2,800°, while the heat of the gases in the furnace would be about 200° or 300° more. The furnace men have to wear deep blue glasses to protect their eyes from the glare of the furnace. With this precau- tion we have not observed their eyes to suffer in any marked degree. The heat of Bessemer metal is about 3,000° to 3,200° ; in this case there is not the same necessity as in the Siemens to watch the hot metal, and the men do not wear glasses. We do not observe any ill effects directly traceable to the heat. In the case of the Siemens men, I should say that without protection the eyes would suffer considerably. After looking at a Siemens fur- nace without glasses, it is several minutes before the eye can see ordinary things again. There is, moreover, a further difference between the two processes, viz. :—Bessemer and Siemens. The former has, as just mentioned, the higher temperature, and the more dazzling glare, but the steel is melted and the process com- pleted in about twenty minutes, and it is only necessary for one man to take close observations, and this he does by means of a spectroscope, and is as far as 30ft. from the molten metal. The Siemens process takes ten hours, and during this period the whole of those engaged will, as the door is frequently drawn up, be tak- ing observations to see whether the melting is proceeding properly. This is constant and regular work, and they are obliged to use coloured glasses. They will stand about loft from the furnace. In addition to all this in these large works are the castings, forgings, rolling of armour plates, and many other things. A huge forging, of perhaps 60 or 80 tons, is drawn out of a furnace with a temperature of from 2,000' to 2,500°, and placed under a power- ful hydraulic press of 10,000 tons power, where, with the men all