Jefferson, Thomas, 1743-1826 [Description of a rain-gauge]
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Gilder Lehrman Collection #: GLC06572 Author/Creator: Jefferson, Thomas, 1743-1826 Place Written: s.l. Type: Autograph note Date: circa 1815 Pagination: 1 p. ; 11.2 x 10.5 cm Order a Copy
A scientific note on the design of a rain gauge. Includes 18 lines on the measurement (volume and weight) of rain, written on the verso of a fragmentary address leaf to John Gads[incomplete]. "The area of the funnel is 10. square inches. The fall of an inch of rain then delivers 10. cubic inches into the funnel." He notes the weight of a cubic inch which was used to mark, successively, each point on the gage and concludes that this system "renders unnecessary all attention to the ratio of the area of the funnel and measuring tube, or to the inequalities of the caliber of the measuring tube." Jefferson refers to James Joyce's Scientific Dialogues, which was issued in 2-3 volumes in 1815, 1817 and 1819, when he writes at the bottom of the page, "see 2. Scientific dialogues. conversn. 48 [or 4b]." Not dated, circa date inferred from publishing date of Joyce's Dialogues.
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