129 



CAVE, EDWARD. 



CAVENDISH, HENRY. 



135 



a great dark cloud rising towards the zenith, the fluid, which began 

 again to be manifest, was found to be negative : the electricity con- 

 tinuing to increase and the rain falling copiously, he pulled in the kite 

 lest some serious accident should happen; and in doing this, he 

 received many strong shocks in hia arms, breast, and legs. He 

 frequently made experiments of this kind, with kites which were 

 about four feet long and two feet wide ; the string was of common 

 twine twisted with threads of fine copper-wire. 



He invented an instrument called a ' condenser of electricity,' which 

 consisted of a tin plate between two parts of a wooden frame covered 

 interiorly with gilt paper : the plate was isolated by being supported 

 on glass pillars ; and one edge being connected with the body contain- 

 ing the electricity, the effect of the condensation was shown, at the 

 opposite edge, by the electrometer. He invented also a ' multiplier ' 

 of electricity, which consisted of two brass plates insulated by being 

 supported on g!a->s pillars, and of a third plate which could be insu- 

 lated or uninsulated at pleasure : this last being fixed to a lever which 

 turned on a pivot, after receiving electricity from one of the former 

 plates, conveyed it to the other, with which an electrometer was con- 

 nected : returning from the second plate to the first it received a 

 fresh supply of electricity, which it conveyed in like manner to the 

 other ; and so on, till a sufficient quantity was accumulated on the 

 latter. 



Among his experiments was one in which were exhibited some 

 remarkable phenomena of the electricity in glass tubes containing 

 mercury. The mercury was boiled in the tube, and the latter being 

 afterwards sealed, on elevating and depressing alternately the ends, 

 electricity was excited by the friction of the mercury : this changed 

 from positive to negative, and the contrary, as the tube was placed in 

 direct and inverted positions. 



Cavallo invented also a simple micrometer consisting of a thin and 

 narrow slip of mothi.r-of-pearl divided into parts each equal to l-200th 

 of an inch ; this being fixed in the diaphragm of a telescope, at the 

 focus of the eye-glass, served for measuring small angles. 



Besides four Bakerian lectures on thermomutrical and magnetical 

 phenomena, and several papers on electricity and other subjects, in 

 the ' Philosophical Transactions,' Cavallo published, in London : 1, 

 ' A Complete Treatise on Electricity,' 8vo, 1777 ; 2, ' An Essay on the 

 Theory and Practice of Medical Electricity,' 8vo, 1780; 3, 'A Treatise 

 on the Nature and Properties of Air,' &c., 4to, 1781 ; 4, 'The History 

 and Practice of Aerostation,' 8vo, 1785; 5, ' Mineralogical Tables,' 

 1785; 8, 'A Treatise on Magnetism in Theory and Practice,' 8vo, 

 1787 ; 7, ' Description and Use of the Mother-of-Pearl Micrometer,' 

 870, 1793 ; 8, ' Essay on the Medicinal Properties of Factitious Airs,' 

 &c., 8vo, 1798 ; and 9, ' Elements of Natural and Experimental 

 Philosophy,' 4 vols. 8vo, 1803. 



CAVE, EDWARD, a printer to whom the literary world owes many 

 obligations, was born at Newton in Warwickshire, February 29, 1691. 

 He is principally known as the projector of the ' Gentleman's 

 Magazine,' and as the friend and early patron of Dr. Samuel Johnson, 

 who wrote an account of his life. He died January 10, 1754. 



CAVE, WILLIAM, an eminent scholar and divine, was born 

 December 30th, 1637, at Pickwell in Leicestershire, where his father 

 was rector of the parish. He was admitted at St. John's College, 

 Cambridge, in 1653, took the degree of B.A. in 1656, and that of M.A. 

 in 1660. In 1662 he was admitted to the vicarage of Islington in 

 Middlesex, and some time after became one of the king's chaplains in 

 ordinary. He took the degree of D.D. in 1672, and in 1679 was collated 

 by the Archbishop of Canterbury to the rectory of Allhallows the Great 

 in Thames-street, London. In July 1631 he was incorporated D.D. at 

 Oxford, and in November 1684 was installed canon of Windsor. He 

 resigned his rectory of Allhallows in 1689, and his vicarage of Islington 

 in KJ91, having on the 19th of November 1690 been admittod'to the 

 vicarage of leleworth in Middlesex. He died at Windsor on the 4th 

 of August 1713, and was buried in Islington church, where a monu- 

 ment was erected to his memory. He published two single sermons, 

 one preached before the lord mayor and citizens of London, November 

 5th, 1680, 4to, London, 1680; the other preached before the king, 

 January 18th, 1684-85, 4to, London, 1685. His works of greater 

 importance are : 1. ' Primitive Christianity,' in three parts, 8vo, 

 London, 1672; reprinted several times since. 2. ' Tabulse Ecclesias- 

 ticsc, Tables of the Ecclesiastical Writers,' fol., London, 1674 ; reprinted 

 at Hamburg in 1676 without his knowledge. 3. ' Antiquitates Apos- 

 tolicse ; or, the Lives, Acts, and Martyrdoms of the Apostles,' fol., 

 London, 1676 ; republished in 1702. 4. ' Apostolic! ; or, the History 

 of the Lives, Acts, Deaths, and Martyrdoms of those who were 

 Contemporaries with or immediately succeeded the Apostles ; as also 

 of the most eminent of the Primitive Fathers for the first three hundred 

 years : to which is added, a Chronology of the three first Ages of the 

 Ii," foL, London, 1677. 5. ' Ecclesiastic! ; or, the History of the 

 Lives, Acts, Deaths, and Writings of the most eminent Fathers of the 

 Church that flourished in the fourth century,' fol., London, 1682. 

 6. ' A Dissertation concerning the Government of the Ancient Church," 

 8vo, London, 1683. 7. 'A serious Exhortation, with some important 

 Advices, relating to the late cses about Conformity, recommended to 

 i'if.R-t .nt Dissenters from the Church of England,' 4to, London, 

 *. ' Chartophylax Ecclesiasticus,' 8vo, London, 1685. 9. 

 ' Hcriptorum Ecclesiastioorum Historia Litcraria a Christo nato usque 



ad Saeculum xiv. facili methodo digest!,' in two parts, fol., the first 

 printed at London in 1688; the second in 169S; republished, fol. 

 Col. Allob., 1705 and 1720. The best edition is that printed at the 

 Clarendon press, by subscription, in two vols. fol., 174043 : it contains 

 the author's last corrections and additions. Cave's ' Lives of tho 

 Apostles," ' Lives of the Fathers,' and his ' Primitive Christianity," are 

 justly esteemed the best books upon those subjects. 



CAVENDISH, HENRY, was the younger son of Lord Charles 

 Cavendish, the brother of the gceat-graudfather of the present Duke 

 of Devonshire, and was bora at Nice, October 10, 1731. Having 

 received his preliminary education in a private school at Hackney, he 

 proceeded to Cambridge and matriculated December 18, 1749. He 

 remained there till 1753, but did not graduate. He had duriug the 

 life of his father a very moderate income, aud his relatives were 

 estranged from him by his determination not to enter upon public or 

 political life ; with the exception of an uncle, who, on his return from 

 abroad in 1773, not being pleased with the conduct of the family 

 towards Cavendish, made the latter heir to his fortune, which was 

 very large. Cavendish devoted himself to mathematics and chemistry, 

 to which his attention was probably turned by his father, who was 

 himself a cultivator of the sciences ; but his success, or at least its 

 evidence, did not come very early, for he was more thau 35 years of 

 age before he published anythibg. He lived a retired life, aud never 

 married ; his manners seem to have been eccentric, aud to strangers 

 very reserved. Indeed this reserve extended far beyond what would 

 by ordinary people be considered as strangers. It is said by Dr. 

 Children (Wilson's ' Life of Cavendish ') that he was so shy towards 

 females that he would never see even a female domestic, and " if an 

 unfortunate maid showed herself, she was immediately dismissed." 

 In order to avoid communication with his servants, it is added by 

 Lord Brougham, " he used to order his dinner daily by a note, which 

 he left at a certain hour on the hall table, whence the housekeeper 

 was to take it." His library, Biot says, was immense, and he fixed it 

 at a distance from his own residence, that he might not be disturbed 

 by those who came to consult it. His friends were allowed to take 

 books, and he himself never withdrew a book without giving a receipt 

 for it He died February 24, 1810, leaving more than a million 

 sterling among different relations. 



Of Cavendish as a philosopher, those who judge by the quantity of 

 brilliant discoveries will not be able to form any opinion. His 

 writings consist of a few papers in the ' Philosophical Transactions," 

 from 1766 to 1809. But in these papers we find methods aud results 

 which have occasioned his being sometimes called the Newton of 

 Chemistry. Without such hyperbole, it may safely be said that he 

 was the first, aud one of the most useful, of those who laid the foun- 

 dation of the science in its modern form. At the time when his first 

 paper appeared, pneumatic chemistry had hnrdly an existence. It is 

 true that different gases were known, that is, had been obtained as 

 results of chemical processes ; but they were uot recognised as distinct 

 substances. It was thought they consisted of common air mixed with 

 foreign matter; and it was not imagined for instance, that the 

 inflammable air produced by operating with one substance was the 

 same as that from another. In 1766, Cavendish for the first time 

 asserted and demonstrated that the fixed air (carbonic acid gas) was 

 the same, whatever was the substance from which it was derived, and 

 the same for the inflammable air (hydrogen), and that neither had the 

 specific gravity of common air. He investigated for the first time the 

 principal properties of the latter substance, and noticed the moisture 

 which results from its combustion. In 1784, he completed the syn- 

 thetical formation of water ; that is, he found the moisture above 

 mentioned to be simple water, and discovered that the remaining 

 element of air, now therefore called nitrogen, was the constituent of 

 nitric acid. He produced this substance by passing the electric spark 

 through air over mercury, and saturating the result with a solution 

 of potash, by which he obtained nitrate of potash, commonly called 

 nitre. It has been keenly debated whether the discovery of the com- 

 position of water should be assigned to Cavendish or to Watt ; but 

 the result of the sifting which the question has undergone, appears to 

 be that each arrived at the discovery by a different method and with- 

 out being at all cognisant of the other's investigations. Cavendish's 

 well-known experiment for the determination of the earth's density is 

 described under ATTRACTION in the ARTS AND SCIENCES. Div. Caven- 

 dish also wrote on the civil year of the Hindus, and on the division 

 of astronomical instruments, and various papers on electricity. 



We resist the temptation to swell this article to an extent propor- 

 tionate to what the reputation of Cavendish deserves. The funda- 

 mentally, if we may use such a word, of his chemical results has not 

 been surpassed by those of any other discoverer in chemistry. But 

 he deserves fame for the great accuracy of his experiments, and the 

 (then) unequalled soundness of his views. One writer asserts that 

 every sentence he has written will bear microscopic examination. A 

 French writer admits (we should say affirms) that he furnished 

 Lavoisier with the materials of his system ; and Sir Humphry Davy 

 in a lecture delivered shortly after the death of Cavendish, speaks as 

 follows : " His processes were all of a finished nature, perfected by the 

 hand of a master ; they required no correction; and though many of 

 them were performed in the very infancy of chemical science, yet 

 their accuracy und their beauty have remained unimpaired amidst the 



