Produced by Colin Bell, Louise Pattison and the Online Distributed Proofreading Team at https://www.pgdp.net CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY: PAPER 23 THE INTRODUCTION OF SELF-REGISTERING METEOROLOGICAL INSTRUMENTS _Robert P. Multhauf_ THE FIRST SELF-REGISTERING INSTRUMENTS 99 SELF-REGISTERING SYSTEMS 105 CONCLUSIONS 114 _The Introduction of_ SELF-REGISTERING METEOROLOGICAL INSTRUMENTS _Robert P. Multhauf_ _The development of self-registering meteorological instruments began very shortly after that of scientific meteorological observation itself. Yet it was not until the 1860's, two centuries after the beginning of scientific observation, that the self-registering instrument became a factor in meteorology._ _This time delay is attributable less to deficiencies in the techniques of instrument-making than to deficiencies in the organisation of meteorology itself. The critical factor was the establishment in the 1860's of well-financed and competently directed meteorological observatories, most of which were created as adjuncts to astronomical observatories._ THE AUTHOR: _Robert P. Multhauf is head curator of the department of science and technology in the United States National Museum, Smithsonian Institution._ The flowering of science in the 17th century was accompanied by an efflorescence of instrument invention as luxurious as that of science itself. Although there were foreshadowing events, this flowering seems to have owed much to Galileo, whose interest in the measurement of natural phenomena is well known, and who is himself credited with the invention of the thermometer and the hydrostatic balance, both of which he devised in connection with experimentation on specific scientific problems. 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. Both of these contemporaries were interested in Galileo's most famous invention, the thermoscope--forerunner of the thermometer--which he developed about 1597 as a method of obtaining comparisons of temperature. The utility of the instrument was immediately recognized by physicists (not by chemists, oddly enough), and much ingenuity was expended on its perfection over a 50-year period, in northern Europe as well as in Italy. The conversion of this open, air-expansion thermoscope into the modern thermometer was accomplished by the Florentine Accademia del Cimento about 1660.