579 



a fortnight before his death, in an article in the Gardener's 

 Chronicle, tracing the origin of the improvements in this branch of 

 horticulture, ascribes the rapid advance in the practice of the 

 art, mainly to the sound and original views promulgated in this 

 essay. 



For the purpose of making more minute and accurate observa- 

 tions upon variations in the atmospheric pressure, Mr. Daniell pro- 

 posed to the Royal Society, in 1830, to construct a barometer in 

 which water should be the fluid used instead of mercury. He was 

 in consequence requested to superintend the construction of such an 

 instrument. Great practical difficulties attended the undertaking, 

 but these he happily surmounted, and the instrument now stands in 

 the Hall of the Apartments of the Royal Society ; he was engaged 

 in re-adjusting it within a few weeks of his decease. On occasion of 

 the late Antarctic Expedition under the command of Captain Sir 

 James Ross, and the establishment by Government of the Magnetic 

 and Meteorological observations, founded a few years since in dif- 

 ferent parts of the British Empire, when the Admiralty applied to the 

 Royal Society for instructions as to the nature and extent of the ob- 

 servations to be made, Mr. Daniell was requested by the Committee 

 of Physics of the Royal Society, to draw up the Meteorological por- 

 tion of these directions. The paper which he then prepared fur- 

 nished the basis of that part of the Report of the Committee, pub- 

 lished in the year 1840, under the sanction of the Royal Society. 



But it was not alone to meteorology, and its practical applications, 

 that his labours were confined ; his researches upon various chemical 

 subjects were not less numerous or important. More than forty 

 original papers, including thirteen on meteorology, were communi- 

 cated by him to various scientific publications ; among others he 

 published several memoirs on Crystallization, and its attendant phe- 

 nomena. Between the years 1830 and 184-4, the Transactions of 

 this Society were enriched by twelve papers on important subjects 

 from his pen. He invented a process for making gas from resin for 

 the purposes of illumination, by which the streets of New York are 

 lighted at the present time. For this improvement he received no 

 other acknowledgment than a vote of a few pounds' worth of books. 

 In the year 1 830, he described in the Philosophical Transactions, a 

 new instrument for measuring high degrees of heat, such as the 

 temperature of furnaces, and the melting-points of metals. By 

 means of this, his pyrometer, he ascertained numerous facts of great 

 interest both in a scientific and in a practical point of view. For 

 the invention of this instrument, which is still the best for the objects 

 intended, the Royal Society awarded him the Rumford Medal. 



After his appointment as Professor of Chemistry in King's College, 

 his researches were turned principally to the phenomena presented 

 by Voltaic Electricity, and they led to the invention of his constant 

 battery ; for this the Royal Society conferred upon him the highest 

 honour in their gift, the Copley Medal for the year 1836. The 

 possibility of maintaining powerful and equable currents of electri- 

 city for any required period, was established by this invention. 



