Measuring Out Sunlight Energy

New Zealand Herald, Volume LXXV, Issue 22949, 29 January 1938, Page 7 (Supplement)

Measuring Out Sunlight Energy

TT is now possible to measure accurately tho amount of energy, given to the individual receiving sun treatment, and also the way in which each individual reacts to this amount. Instead of exposing any weakly individual haphazard to any source of light for any length o? time, the exposure is carefully regulated, according to the type of lamp and tho reaction of the patient For measuring the latter, Sir Leonard Hill and Eidinow have introduced a method of estimating the exact dose required, using an instrument called a "sensitomoter." This consists of a round aluminium plate to which is attached a clockwork mechanism which gradually moves a small screen covering a hole in tho plate. The apparatus is placed over the skin and the test area exposed for different periods to the rays from the lamp; tho erythema, or redness of the skin, produced is used to determine the exact amount which will be most beneficial. This exactitude, which was unknown to the pioneers in this branch of scientific treatment, is of great value in obtaining the best results from exposure to artificial sunlight without discomfort or injury to the patient.— From New Health.