Society in 1748 and in 1760 (_Philosophical
Transactions of the Royal Society of London_, 1748, vol. 45, p. 128;
1760, vol. 51, p. 823). Some systems used a bimetallic thermometer in
the sun and a mercurial instrument in the shade.

[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 ueber 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 Woerterbuch, Goettingen_, 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 Traumueller, _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
Societe 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