Identifier: s4philosophicalm22lond (find matches)
Title: The Philosophical magazine; a journal of theoretical, experimental and applied physics
Year: 1798 (1790s)
Authors:
Subjects: Physics
Publisher: London Taylor & Francis (etc.)
Contributing Library: Gerstein - University of Toronto
Digitizing Sponsor: University of Toronto

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and difficult study. We require means of print-ing, not lists of dry figures, but actual charts which should recordmeteorological obsenations pictorially and geographically, with-out sacrificing detail. It is then in the belief that an attempt Ihave just made to supply this desideratum might interest someof your readers, and perhaps lead to useful suggestions, that Iforward the accompanying chart. (Plate II). It has been printedwith moveable types, which I designed and caused to be cast; andI am much indebted to Mr. W. Spottiswoode, who printed it, forhis aid in carrying out my ideas. The map simply incorporatesthe newspaper data of the day to which it refers, and was j)rinted,not with any scientific object, but solely for the purpose ofexperiment. Explanation of the Si/ntbols. The shade signifies cloud, of an amount proportional to itsdepth. The types witii lines round them, I , stand for rain. Cloud tyj)eB jjavc been interpolated where observations were* Commuuicutcd by the Author.
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On the Cwves situate on a Surface of the Second Order. 35 wanting. The horseshoes show the direction of the wind cur-rent: thus, ~^ means wind/ro?;i the west. An inchxded spot 3^, or line 3^, or cross 2>> respectively signify that the wind is gentle, moderate, or strong; where neither dot, line, nor crossare inserted, the force of the wind is unknown. Thermometricaldata are expressed by figures, printed below the wind symbols.The first two figures of each set stand for the height of the ordi-nary thermometer, and the last figure (in a different type) forthe difference between this and the thermometer with a wettedbulb. To save confusion of figures, barometer heights are notinserted on the face of the present map; but lines of equal baro-metric pressure have been deduced from the existing observations,and the places where lines corresponding to each integral one-tenth of an inch cut the marginal columns, have been marked.Thus a straight line joining the pair of figures, 297, is a

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