316 ALVAN CLARK. 



and his eldest sou, by undertaking the construction of a small reflecting 

 telescope as a juvenile experiment, first directed his attention to optical 

 work. The occupation, once begun, proved too interesting to be laid 

 aside, but some time necessarily passed before astronomers began to 

 discover the surprising excellence of the instruments which were pro- 

 duced by a maker who had received no professional training as an 

 optician, and had reached middle life without intending to become one. 

 Mr. Clark began the manufacture of telescopes at Cambridge in 1846, 

 with the aid of his two sons, and proved the superiority of his work by 

 astronomical observation, during which he discovered several double 

 stars, requiring, on account of the close proximity of their components, 

 an instrument of unusual defining power for the recognition of their 

 character. His correspondence upon this subject with the distinguished 

 English observer of double stars, the Rev. W. R. Dawes, led to the 

 purchase by Mr. Dawes of some of his telescopes, and to the growth of 

 his reputation among other astronomers. His portrait painting was 

 laid aside, to be resumed only as the recreation of his old age, when it 

 appeared that his eye and hand still preserved the accuracy which had 

 distinguished his youth. As an additional illustration of this accuracy, 

 it may here be mentioned that, during the prime of life, Mr. Clark took 

 much interest in practice with the rifle, and greatly distinguished him- 

 self as a marksman. To render assistance in loading the rifle with ac- 

 curacy, he invented a false muzzle, which is still employed among those 

 who have not adopted the breech-loading guns which are now in com- 

 mon use. 



By degrees it appeared that the firm of Alvan Clark and Sons was 

 indisputably at the head of the telescope makers of the world, notwith- 

 standing an entire neglect of all the arts of business competition. It 

 became necessary for aspirants to the possession of a telescope superior 

 to any which had been previously made, to resort to the works at Cam- 

 bridge. In 18G0, the University of Mississippi ordered a telescope 

 eighteen inches in aperture. The outbreak of civil war the next year 

 changed the destination of this instrument to Chicago ; but, before it 

 left Cambridge, the companion of Sirius, a body previously known only 

 in theory, was discovered with its aid. In 1877, with the twenty-six- 

 inch refractor of the United States Naval Observatory, also the work 

 of Alvan Clark and Sons, and the largest instrument of its class then 

 mounted, the two satellites of Mars were discovered. The great Rus- 

 sian Observatory of Pulkowa next demanded a still larger instrument, 

 and finally the Lick Observatory of California called for one even 

 greater. This was the last important work of the firm which he had 



