. Good and bad eyesight : and the exercise and preservation of vision. point of difference from the old Argand is that thesupply of air can only reach the flame by passingthrough metal channels of considerable length, inwhich the air becomes heated to such a degree that,even if superabundant, it would exercise no refrigerat-ing effect. Coincidentally with the researches of Mr. Silber,much good work in the same direction has been doneby another inventor, Mr. Sugg, who also makes Argandgas-burners of great excellence. As between the Silberand the Sugg burners it would be difficult for the un- 21
. Good and bad eyesight : and the exercise and preservation of vision. point of difference from the old Argand is that thesupply of air can only reach the flame by passingthrough metal channels of considerable length, inwhich the air becomes heated to such a degree that,even if superabundant, it would exercise no refrigerat-ing effect. Coincidentally with the researches of Mr. Silber,much good work in the same direction has been doneby another inventor, Mr. Sugg, who also makes Argandgas-burners of great excellence. As between the Silberand the Sugg burners it would be difficult for the un- 210 EYESIGHT. aided eye to assign the palm of superior merit; but,according to a photometric investigation made by , and the results which were embodied in apaper read by him before the Society of Arts, andpublished in the Journal of the Society for the 7thFebruary, 1879, the Silber burners are decidedly, al-though not very greatly, the better of the two. Forthe same consumption of the same kind of gas, thelight given by the best form of Silber Argand burner
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Keywords: ., bookcentury1800, booksubj, booksubjecteye, booksubjecteyediseases
