A Flexible Catheter

To John Franklin Dear Brother Philada. Dec. 8. 1752 Reflecting yesterday on your Desire to have a flexible Catheter, a Thought struck into my Mind how one might possibly be made: And lest you should not readily conceive it by any Description of mine, I went immediately to the Silversmith’s, and gave Directions for making …

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The Kite Experiment


As frequent Mention is made in the News Papers from Europe, of the Success of the Philadelphia Experiment for drawing the Electric Fire from Clouds by Means of pointed Rods of Iron erected on high Buildings, &c. it may be agreeable to the Curious to be inform’d, that the same Experiment has succeeded in Philadelphia, …

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The Magical Circle

To Peter Collinson SIR, I am glad the perusal of the magical squares afforded you any amusement. I now send you the magical circle. Its properties, besides those mentioned in my former, are these. Half the number in any radial row, added with half the A Magic Circle of Circles. central number, make 180, equal …

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The Arithmetical Curiosity


To Peter Collinson SIR, According to your request, I now send you the Arithmetical Curiosity, of which this is the history. Being one day in the country, at the house of our common friend, the late learned Mr. Logan, he shewed me a folio French book, filled with magic squares, wrote, if I forget not, …

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