Robert P. Multhauf

“ In the course of devising these experiments Hooke became perhaps the most prolific instrument inventor of all time. He seems to have invented the first wind pressure gauge, as an aid to seamen, and he improved the bathometer, hygrometer, hydrometer, and barometer, as well as instruments not directly involved in measurement such as the vacuum pump and sea-water sampling devices. ”

“ Long experience had demonstrated to the meteorologists of the 1840's that the principal obstacle to the success of self-registering instruments was friction. Forbes had indicated that the most urgent need was for automatic registration of wind data, as the erratic fluctuation of the wind demanded more frequent observation than any manual system could accomplish. ”

“ The movement of the mercury over a certain minute distance within the tube served as a switch to energize an electrical recording system. Hipp, who was perhaps the latest of this group, first applied the aneroid barometer (fig. 8) to self-registration. The idea of the aneroid—an air-tight bellows against which the atmospheric pressure would act—had been advanced by Leibniz in the 17th century and had been the subject of a few abortive experiments in the 18th century. Not until 1848 was an instrument produced that was acceptable to users of the barometer. ”

“ Nearly 200 years of observation had not, however, noticeably improved the weather, and the naive faith in the power of instruments to reveal its mysteries, which had possessed many an early meteorologist, no longer charmed the scientist of the early 19th century. ”

“ Its complexity is sufficient reason for its ephemeral history, but complexity in machine design was the fashion of the time and Hooke may have intended no more than a mechanistic tour de force. On the other hand, he may have recognized the desideratum to which later meteorologists frequently returned—the need for simultaneous observations of several instruments on the same register. In any case, no instrument so comprehensive seems to have been attempted again until the middle of the 19th century, when George Dolland exhibited one at the Great Exhibition in London (see fig. 3) . ”

“ Not for over a century was the first thoroughgoing attempt made at systematic observation. There was a meteorological section in the Academy of Sciences at Mannheim from 1763, and subsequently a separate society for meteorology. In 1783, the Academy published observations from 39 stations, those from the central station comprising data from the hygrometer, wind vane (but not anemometer) , rain gauge, evaporimeter, and apparatus for geomagnetism and atmospheric electricity, as well as data from the thermometer and barometer. ”

“ The most general mistake probably consists in the idea that Meteorology, as a science, has no other object but an experimental acquaintance with the condition of those variable elements which from day to day constitute the general and vague result of the state of the weather at any given spot ”

“ It should also be noted that the photographic and electromagnetic systems of the 19th century seem to have been something of an interlude, for some of the latest and most durable (all of Draper's and Richard's instruments and Marvin's barograph) were purely mechanical instruments, as had been those of Hooke and Wren. If we conclude that the 19th-century instruments were more accurate, we should also recall Forbes' comments upon the question of instrumental accuracy. ”

“ Dolland's barometer was a wheel instrument controlling a hammer. His thermometric element consisted of 12 balanced mercury thermometers. Its mode of operation is not clear, but it probably was similar to that of the thermometer developed by Karl Kreil in Prague about the same time (fig. 4) . Dolland's wind force indicator consisted of a pressure plate counterbalanced by a string of suspended weights. Altogether, it is not clear that Dolland's instrument was superior to Hooke's, or that its career was longer. ”

“ By 1900 these simple and inexpensive instruments had relegated to the scrap pile, unfortunately literally, the elegant products of the mass attack of observatory directors in the 1860's on the problem of the self-registering thermometer and barometer. [34]
Conclusions
In view of the rarity of special studies on the history of meteorological instruments, it is impossible to claim that this brief review has neglected no important instruments, and conclusions as to the lineage of the [Pg 115] late 19th century instruments can only be tentatively drawn. ”

“ In the United States the office of the Surgeon General, U. S. Army, began the first systematic observation in 1819, using only the thermometer and wind vane, to which were added the barometer and hygrometer in 1840-1841 and the wind force anemometer, rain gauge, and wet bulb thermometer in 1843. ”

“ It would appear to have been a difference of degree—the maturation in the 19th century of certain features [Pg 116] of the 17th. The most important of these features were the spread throughout the western world of the spirit that had animated the scientific societies of Florence and London, the continued popularity of the astronomical observatory as an object of the philanthropy of an affluent society, and the continued existence of the nonspecialized scientist. ”

“ Many, if not most, of the other Italian instrument inventors of the early 17th century were his disciples. Benedetto Castelli, being interested in the effect of rainfall on the level of a lake, constructed a rain gauge about 1628. Santorio, well known as a pioneer in the quantification of animal physiology, is credited with observations, about 1626, that led to the development of the hygrometer. ”

“ He also notes that in 1670 Hooke had described two other types of rain gauge in which a bucket was counterbalanced in one case by a string of bullets and in another by an immersed weight. But here again, Sprat records the invention of a tipping-bucket gauge by Wren before 1667.
Hooke has been generally regarded as the first inventor of an anemometer, in 1662. [13] But this invention was a pressure-plate gauge—that is, a metal plate held with its face against the wind—whereas the gauge used with the weather clock is clearly a windmill type, of which type this may be the first. ”

“ Top (from left) : maximum-minimum thermometer of Professor Phillips, dry-bulb and wet-bulb thermometers, and mercurial barometer by Green of New York. Lower left: rain gauge. The wet-bulb thermometer, although typical, is actually a later instrument. The rain gauge is a replica.
Galileo also inspired the barometer, through his speculations on the vacuum, which, in 1643, led his disciple Torricelli to experiments proving the limitation to nature's horror of a vacuum. Torricelli's apparatus, unlike Galileo's thermoscope, represented the barometer in essentially its classical form. ”

“ As a wind velocity instrument all six systems used the cup-anemometer developed by Robinson in 1846, an instrument whose chief virtue was the care which its inventor had taken to work out the relationship between its movement and the actual velocity of the wind. [30] Beckley and Draper caused it to move a pencil through gearing ”

“ It also saw the development of a new method of electrical 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 meteorological register which "records the indications of the [Pg 107] barometer, thermometer and the psychrometer [meaning wet-bulb thermometer] every half hour ... and prints the results on a sheet of paper in figures," running a week unattended. ”

“ A few of these instruments, such as the Marvin barograph, survived for some time because of their superior accuracy. Even as museum pieces, only a few exist today.
U.S. GOVERNMENT PRINTING OFFICE, 1961. ”

“ But it is apparent that Hooke's clock was actually used for some time.
[Pg 102]
Figure 3.—Dolland's "atmospheric recorder": 1, siphon and float barometer; 2, balance (?) thermometer; 3, hygrometer; 4, electrometer; 5, float rain gauge; 6, float evaporimeter; 7, suspended-weight wind force indicator; 8, wind direction indicator; 9, clock; 10, receivers for rain gauge and evaporimeter. (From Official ... Catalogue of the Great Exhibition, 1851, London, 1851, pt. 2) .
[Pg 103] The 17th century was not entirely unprepared for the idea of such a self-registering instrument. ”