Litchfield, Isaac W, Massachusetts Institute of Technology. Society of Arts · Boston, Mass. : The Society · leaf 67
for the eyes, and can cause a violent sunburn on the skin. The second problem is to get the rays Figure 2 in contact with the bacteria in the water. A still more recent method is the use Clear colorless water will allow the light of the ultraviolet rays about which we to penetrate about one foot,… … can be instantly killed if prop- Figure 3 erly exposed to ultraviolet light. The action is probably purely necessary to have the water exposed to photochemical, and does not take place the light in thin layers, as well as to have it through the intermediate formation of as clear and colorless as is…
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