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Progress, Volume II, Issue 4, 1 February 1907, Page 126

Dr. Lendenfeld m 1904, writing in the periodical Naturwissenschafthche, adds his testimony with a table in which the albatross figures at 67 square millimetres of wing surface to the gramme of weight, the Laughing Gull at 336, and the gnat at 10,000. It is interesting to note that the same authority worked out a table on that occasion from which it appears that a man of ordinary weight (90 kilogrammes) can be supported m the air by two wings " furnishing together 2 7 square metres of surface " Compare this with the indispensable 72 feet spread of the judgment by analogy. The above table exhibits the same paradoxical law that the greater the creature the smaller the relative supporting force This is now known as Langley's law and accepted Before definitely coming to the conclusion himself Mr Langley made long and patient investigation For the test he installed an apparatus consisting of "a whirling table of unprecedented size mounted in the open air and driven round by a steam engine so that the end of the revolving arms swept through a circumference of 200 feet at all speeds up to 70 miles an hour. At the end of this arm was