Produced by The Online Distributed Proofreading Team at https://www.pgdp.net (This file was produced from images generously made available by The Internet Archive.) A TREATISE ON METEOROLOGICAL INSTRUMENTS. LONDON: PRINTED BY WILLIAMS AND STRAHAN, 7 LAWRENCE LANE, CHEAPSIDE, E.C. A TREATISE ON METEOROLOGICAL INSTRUMENTS: EXPLANATORY OF THEIR SCIENTIFIC PRINCIPLES, METHOD OF CONSTRUCTION, AND PRACTICAL UTILITY. BY NEGRETTI & ZAMBRA, METEOROLOGICAL INSTRUMENT MAKERS TO THE QUEEN, THE ROYAL OBSERVATORY, GREENWICH, THE BRITISH METEOROLOGICAL SOCIETY, THE BRITISH AND FOREIGN GOVERNMENTS, ETC. ETC. ETC. LONDON: PUBLISHED AND SOLD AT NEGRETTI & ZAMBRA'S ESTABLISHMENTS: 1 HATTON GARDEN, E.C., 59 CORNHILL, E.C., 122 REGENT STREET W., AND 153 FLEET STREET, E.C. 1864. _Price Five Shillings._ PREFACE. The national utilisation of Meteorology in forewarning of storms, and the increasing employment of instruments as weather indicators, render a knowledge of their construction, principles, and practical uses necessary to every well-informed person. Impressed with the idea that we shall be supplying an existing want, and aiding materially the cause of Meteorological Science, in giving a plain description of the various instruments now in use, we have endeavoured, in the present volume, to condense such information as is generally required regarding the instruments used in Meteorology; the description of many of which could only be found in elaborate scientific works, and then only briefly touched upon. Every Meteorological Instrument now in use being fully described, with adequate directions for using, the uninitiated will be enabled to select those which seem to them best adapted to their requirements. With accounts of old or obsolete instruments we have avoided troubling the reader; on the other hand, we were unwilling to neglect those which, though of no great practical importance, are still deserving of notice from their being either novel or ingenious, or which, without being strictly scientific, are in great demand as simple weather-glasses and articles of trade. We trust, therefore, that the work (however imperfect), bearing in mind the importance of the subject, will be acceptable to general readers, as well as to those for whose requirements it has been prepared. The rapid progress made in the introduction of new apparatus of acknowledged superiority has rendered the publication of some description absolutely necessary. The Report of the Jurors for Class XIII. of the International Exhibition, 1862, on Meteorological Instruments, fully bears out our assertion, as shown by the following extract:--