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NA TURE 



{Jan. 27, 1887 



depends, (i) on the height ; (2) on the velocity of the 

 meteorite ; (3) on its size ; and (4) on the configuration 

 of the country over which it passes. He refers to the 

 observation of Saussure that a pistol fired at a height of 

 5000 metres makes \ery little noise : he then points out 

 that at a height of 100,000 metres the density of the air 

 is reduced to the small value of 0-000,000,004 krg. ; the 

 temperature being supposed to be - 200° C. In such a 

 medium as this a meteorite could produce no sound, 

 although it might give out a very brilliant light, because 

 Its temperature and light depend not on the absolute value, 

 but on the rapid change of density. 



SIR JOSEPH WHITWORTH 



ON Saturday night last, Sir Joseph Whitworth died 

 at the English Hotel, Monte Carlo. In the de- 

 partment of mechanical engineering there is, perhaps, no 

 greater name, and his career was one upon which his 

 countrymen may well look back with pride and pleasure. 

 He was born on December 21, 1S03, at Stockport, where 

 his father was a schoolmaster. At the age of twelve he 

 was sent from his father's school to Mr. Vint's academy 

 at Idle, near Leeds, where he remained until he was four- 

 teen, when he was placed with his uncle, a cotton-spinner 

 in Derbyshire. Here he made himself familiar with the 

 construction and working of all the machines then used 

 in cotton-spinning. If he had chosen, he might perhaps 

 have inherited his uncle's property, but he was already con- 

 scious of the true bent of his genius, and after six years' ser- 

 vice, being unable to emancipate himself in a more regular 

 manner, he ran away to Mancheste-r. At Manchester he 

 remained for four years, working in the shops of Messrs. 

 Crighton and other employers, and obtaining a thorough 

 mastery of the methods of manufacturing cotton-machi- 

 nery. Recognising the necessity of wide e.xperience, he 

 went to London when he had secured all the practical 

 knowledge that could be obtained in his special line at 

 Manchester, and he was fortunate enough to be employed 

 by Maudslay, who soon learned to appreciate his excep- 

 tional gifts, and took him into his own private workroom, 

 and placed him next to Hampson, the best workman in 

 the establishment. From Maudslay's, Mr. Whitworth 

 went to Holtzapfel's, and afterwards to Clements's, where 

 Babbage's calculating-machine was being constructed. 

 During his residence in London, Mr. Whitworth began 

 the splendid series of inventions which were to secure for 

 him the foremost place among the mechanical engineers 

 of his period. His first important self-imposed task was 

 to construct the true plane, by which tool-makers might be 

 enabled to produce, for all kinds of sliding tools, surfaces 

 on which the resistance arising from friction would be re- 

 duced to a minimum. The work to be achieved was one 

 of immense difficulty, and his fellow-workman, Hampson, 

 used to laugh at him for having undertaken an impossible 

 job. Mr. Whitworth, however, was a man of extraordinary 

 tenacity of purpose, and did not allow himself to be dis- 

 couraged. At last he succeeded, and showed his friend 

 the perfect plane he had produced. " You've done it," 

 said Hampson, who was astounded by a result which he 

 had always thought to be beyond the reach of human 

 effort. 



In 1833, at the age of thirty, Mr. Whitworth, feeling 

 that he might now safely trust to his own energies, re- 

 turned to Manchester and opened a shop for the manu- 

 facture of engineers' tools. He was far from thinking 

 that his first triumph had given the full measure of his 

 powers. Already he had been working at another very 

 complicated problem — how to do away with the incon- 

 veniences caused by variations in the pitch and thread of 

 the screws used in the construction of machinery. In 

 this enterprise he was as successful as in his first great 

 undertaking. Obtaining specimens of the screws made 



by leading manufacturers, he constructed one which, 

 without being exactly like any one of those before him, 

 was the average of them all. It was everywhere accepted, 

 and its introduction marked an era in the history of the 

 manufacture of machinery. The advantage derived from 

 the invention is that every screw of the same diameter has 

 now a thread of the same pitch and of the same number 

 of turns to the inch, and that all screws of the same size 

 are interchangeable. His next achievement was the con- 

 struction of an instrument capable of measuring the one- 

 millionth part of an inch. This instrument was so deli- 

 cate that when a steel bar 3 feet in length was warmed 

 by momentary contact with a finger-nail, it at once indi- 

 cated the expansion due to this slight cause. 



As a maker of engineers' tools Mr. Whitworth of 

 course soon became famous, and in 1853 he was sent 

 to America as one of the Royal Commissioners to 

 the New York Exhibition. Afterwards he drew up 

 a remarkable report on American manufacturing in- 

 dustry. On his return to England it was suggested 

 by the late Lord Hardinge that the great mecha- 

 nician, whose fame was now firmly established, should 

 be asked by the Government to design and pro- 

 duce machinery for the manufacture of rifles for the army. 

 The rifles at that time issued to the army were carefully 

 examined by him, and he decided that if his services were 

 to be of any avail it would be necessary for him to deter- 

 mine the form and dimensions which would produce the 

 best results. With an alacrity very unusual in such matters, 

 the Government consented to erect in his private grounds 

 at Rusholrae, near Manchester, a shooting-gallery 500 

 yards long. Here Mr. Whitworth laboured assiduously, 

 trying many kinds of experiment, and at every stage of 

 his progress making absolutely sure of his ground before 

 advancing a step towards fresh conclusions. The result 

 of his investigations was to revolutionise the manufacture 

 of rifles. As the Times has said, " he determined, by 

 absolute and precise experiment, the effects of every con- 

 ceivable pitch and kind of rifling,and of every length of pro- 

 jecti!e,from the sphere toone of twenty diameters in length; 

 and he settled once for all the conditions of trajectory and 

 of accuracy of flight." The significance of his efforts 

 began to be understood by every one when, at the first 

 Wimbledon meeting. Her Majesty fired the first shot from 

 a Whitworth rifle, placed on a mechanical rest sliding 

 upon true planes. At 400 yards' range the bullet struck 

 the target on its vertical diameter, one inch and a quarter 

 above the intersection of the horizontal. What he esta- 

 blished with regard 10 rifles he found to be in the main true 

 with regard to weapons of a larger calibre, and he 

 proved the importance of this fact by constructing a 

 series of magnificent cannon. 



In the course of his inquiries as to the principles which 

 ought to be observed in the manufacture of rifled small 

 arms and ordnance, Mr. Whitworth became penetrated 

 by the conviction thai a new material must be provided, 

 since mild steel was apt to be rendered unsound by the 

 imprisonment of escaping gases during the process of 

 cooling from the molten state. He solved the problem 

 by using great hydraulic presses for the squeezing of the 

 molten metal in the act of cooling, so that the particles 

 might be brought into closer contact and the gases 

 liberated. The steel produced by this method is remark- 

 able for its lightness, strength, and tenacity, and is largely 

 used in the construction of boilers, screw-propeller shafts, 

 and for other purposes. 



In 1869 Mr. Whitworth was created a baronet, and he 

 had already been for some years a Fellow of the Royal 

 Society and a D.C.L. of Oxford. He had amassed 

 wealth, and thoroughly appreciated all the advantages it 

 secured for him. He was, however, a man of enlight- 

 ened ideas and generous impulses, and early in 1869 he 

 did splendid service to mechanical and engineering in- 

 dustry by founding the Whitworth Scholarships, which 



