Dictionary of National Biography, 1885-1900/Cavallo, Tiberius

1384093Dictionary of National Biography, 1885-1900, Volume 09 — Cavallo, Tiberius1887Robert Hunt

CAVALLO, TIBERIUS (1749–1809), natural philosopher, was born in Naples in 1749, his father being a physician practising in that city. At an early age he left Italy, and settled for life in this country. In October 1775 he published a notice of ‘Extraordinary Electricity of the Atmosphere observed at Islington.’ This was reprinted in ‘Sturgeon's Annals of Electricity’ (1843, p. 158). Cavallo was the inventor of several philosophical instruments and pieces of apparatus for electrical and chemical experiments. Much ingenuity was shown in their construction, all his instruments for the measurement of the quantity and force of electricity being remarkable for their extreme delicacy and correctness.

Cavallo was on 9 Dec. 1779 admitted as a fellow of the Royal Society. In 1781 he published a quarto volume entitled ‘A Treatise on the Nature and Properties of Air and other permanently Elastic Fluids.’ In this treatise he deals with chemistry and hydrostatics as they bear on the composition and physical properties of aeriform and other fluids. He examines with caution most of Dr. Priestley's experiments on air, and institutes many new ones, to determine more accurately the composition of the atmosphere and the conditions of inflammable and fixed air. Phlogisticated air forms the subject of inquiry, but it is evident that Cavallo could not receive the hypothesis of phlogiston, and yet did not feel himself on such sure ground as would justify his advancing any new doctrine. His investigations into the influences of air and light on the growth of plants are very original, and advanced him very nearly to the discovery of many new truths in connection with organic life.

In 1786 Cavallo published his ‘Complete Treatise on Electricity,’ which reached a third edition in 1795. It proves him to have been a true philosopher, holding his judgment suspended until he is satisfied by demonstrative evidence of the truth. In 1787 he published ‘A Treatise on Magnetism in Theory and Practice,’ which embraces all that was known on the subject at the time; and in 1797 he contributed to ‘Nicholson's Journal’ a paper ‘On the Multiplier of Electricity.’ Cavallo gave some attention to aerostation, on the history and practice of which he published a treatise in 1785. About this period meteoric phenomena claimed his observation. In the latter part of his life he devoted much time to the use of electricity as a curative agent. In 1780 he published a work ‘On Medical Electricity,’ and in 1798 the ‘Medicinal Properties of Factitious Air.’ His latest large work was ‘Elements of Natural and Experimental Philosophy’ (1803, 4 vols. 8vo). He contributed an article on meteors to the ‘Philosophical Transactions.’ Cavallo died, at the age of sixty, in 1809.

[Nicholson's Journal, 1797, p. 394; Catalogue of Scientific Papers, Royal Society; Transactions of the Royal Society; Watt's Bibl. Brit. 1824.]

R. H-t.

Dictionary of National Biography, Errata (1904), p.58
N.B.— f.e. stands for from end and l.l. for last line

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338 i 19 Cavallo, Tiberius: for Watt's 'Bibliotheca Britannica' read 'The Philosophical Transactions'