Scale about i-i6tii. 

 BAROGRAPH, b^ 



SELF-RECORDING MERCURIAL BAROMETER, £58. 



Figure 6. — Photographic registering mercurial barometer, typical commercial version. (Frorrt 

 J. J. Hicks, Catalogue of . . . Meteorological Instruments, London, n.d., about 1870.) 



these "systems" were nained were directors of astro- 

 nomical observatories, which were, at this time, the 

 most active centers of meteorological observation. 

 Wild was at the Bern Observatory,-- Secci at the Papal 

 Observatory, Rome,-^ and George Hough at the 

 Dudley Observatory, Albany, New York.^* While 

 the Signal Corps seems to have acquired all of the 

 principal "systems," some interesting instruments 

 were developed at still other observatories, notably by 

 Kreil at the astronomical observatory in Prague.-^ 

 The principal impetus for this full-scale mechaniza- 

 tion of observation undoubtedly came from the 

 directors of astronomical observatories. 



Thus within little more than the decade of the 

 1 860's were developed five new systems of meteoro- 



22 P. H. Carl, Reperlorinm Jiir physikalische Technik, Munich, 

 1867, p. 162flF. 



23 E. Lacroix, Etudes sur V Exposition de 1867, Paris, 1867, vol. 2, 

 p. 313ff. See also, Reports of the U.S. Commissioners to the Paris 

 Universal Exposition, 1867, vol. 3, Washington, 1870, p. 570ff. 



21 Annals of the Dudley Observatory, 1871, vol. 2, p. vii ff. 

 -^ Karl Kreil, Entivnrf eines meteorologischen Beobachtungs-Sys- 

 temsfiir die osterreichische Monarchie, Vienna, 1850. 



logical self-registry that were sufficiently well thought 

 of to be adopted or copied by observatories outside 

 their places of origin. Wild and Draper tell us that 

 it was decided when their respective observatories 

 were established — in 1860 and 1868 — that all instru- 

 ments should be self-registering. Each was obliged 

 to design his own, being dissatisfied with the photo- 

 graphic registers commercially available. The de- 

 velopment of these systems would therefore appear to 

 have been due, in part, to the general spread of a 

 conviction that satisfactory instruments were at- 

 tainable. 



This confidence was warranted, for the decade of the 

 1850's had seen the appearance of major innovations 

 in the basic instruments — thermometer, barometer, 

 and wind velocity indicator — that made available 

 instruments more adaptable to self-registration. It 

 also saw the development of a new method of elec- 

 trical registration derived from the telegraph. Sir 

 Charles Wheatstone initiated this small revolution 

 in 1843 when he reported to the British Association 

 that he had constructed an electromagnetic meteoro- 

 losjical resfister which "records the indications of the 



106 



BULLETIN 228: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



