[28] This instrument has been persistently associated with Sir Samuel Morland (1625-1695). For example, A. Sprung of the Deutsche Seewarte described his own balance-barometer as a "Wagebarograph nach Samuel Morland" (in L. Loewenherz, _Bericht über die wissenschaftlichen Instrumente auf der Berliner Gewerbeausstellung im Jahre 1879_, Berlin, 1880, p. 230ff). Sprat (_op. cit._ footnote 10, p. 313) reported that Wren had proposed "balances to shew the weight of the air by their spontaneous inclination." This must, therefore, be Wren's invention, unless he got it from Morland, who does not seem to have published anything about the barometer but only to have described some ideas to a friend. But Morland's was probably the _inclined_ and not the _balance_ barometer. (See under "barometer" in Charles Hutton, _Mathematical and Philosophical Dictionary_, London, 1796, vol. 1; also J. K. Fischer, _Physikalisches Wörterbuch, Göttingen_, 1798). [29] Leibniz, in several letters--beginning with one to Denys Papin on June 21, 1697--proposed the making of a barometer on the model of a bellows. Of subsequent versions of such a barometer, that of Vidi (described by Poggendorff, _Annalen der Physik und Chemie_, 1848, Band 73, p. 620) is generally regarded as the first practical aneroid (see also Gerland and Traumüller, _op. cit._ footnote 1, pp. 239, 323). [30] T. R. Robinson, "Modification of Dr. Whewell's Anemometer for Measuring the Velocity of the Wind," _Report of the 16th Meeting of the British Association for the Advancement of Science, 1846_, 1847, pt. 2, p. 111. [31] Abbe, _op. cit._ (footnote 19), pp. 263-264. [32] Because of its superior accuracy to the aneroid barograph, Marvin's barometer was in use through the 1940's. See R. N. Covert, "Meteorological Instruments and Apparatus Employed by the United States Weather Bureau," _Journal of the Optical Society of America_, 1925, vol. 10, p. 322. [33] Both of Richard's instruments (described in _Bulletin Mensuel de la Société d'Encouragement pour l'Industrie Nationale_, November 1882, ser. 3, vol. 9, pp. 531-543) were in use at Kew by 1885 and at the U.S. Weather Bureau by 1888. The firm of Richard Freres claimed in 1889 to have made 7,000 registering instruments, of which the majority were probably thermographs and barographs. At that time, certainly no other maker had made more than a small fraction of this number of self-registering instruments. The origin of Richard's thermograph seems to have been the "elastic manometer" described by E. Bourdon in 1851 (_Bulletin de la Société d'Encouragement pour l'Industrie Nationale_, 1851, no. 562, p. 197). While attempting to restore a flattened still-pipe, Bourdon had discovered the property of tubes to change shape under fluid pressure. The instrument he developed in consequence became the standard steam pressure gauge.