IT need not be said that in astronomical observation it is always desirable, to say the least of it, to have a tolerably correct estimate of the magnifying power actually in use. This has hitherto ...
Invented by an electrical engineer named Francis Cutler Ellis (1890-1957), the Ellis Micro-Dynameter promised to make the human body “function as a simple electrical cell and measure the current it ...
THE letter from the Rev. T. W. Webb in your last number is a very tantalising letter. He tells us, and we could not wish to have a better authority, that a new dynameter has been invented by the Rev.
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