120 THE POPULAR SCIENCE MONTHLY. 



honors of the Jardin des Plantes, and Gay-Lussac and Larrey enter- 

 tain her with chat. ... At Geneva she met Mrs. Marcet, whose ' Conver- 

 sations on Chemistry ' were said by Faraday to have first opened his 

 mind to the wonders of that science. There, too, were Sismondi and 

 De la Rive. A letter from De Candolle, whose acquaintance she had 

 made there, gives shortly afterward some excellent hints for the prose- 

 cution of the botanical studies in which she had already made much 

 progress. The interest which she takes in the most diverse branches 

 of knowledge makes every one forward to bring her the first intelli- 

 gence of anything new or of significance. Dr. Young is eager to sub- 

 mit an Egyptian horoscope he has that evening deciphered from a 

 papyrus of the age of the Ptolemies ; Wollaston hurries to Hanover 

 Square to show, by means of a small prism in a darkened room, the 

 seven dark lines he had discovered crossing the solar spectrum, the 

 germ of the most important series of modern discoveries in solar phys- 

 ics ; Babbage discourses over his analytical engine ; Sir J. Herschel 

 exhibits nebulae and binary stars in the field of his great reflector ; 

 Ada, Byron's daughter, afterward Lady Lovelace, compares difliculties 

 with Mary Somerville in mathematics. Among her most intimate and 

 valued friends was Maria Edgeworth, to which number were later 

 added Joanna Baillie and her sister. Year by year her acquaintance 

 and correspondence grew, until they included well-nigh every name 

 of distinction in literature or science." 



This activity continued till the last day of her life. She spent 

 many years in Italy, having removed there for the benefit of the health 

 of her husband, who died at Florence in 1861 at the age of ninety- 

 one, and continuing to reside there till her death. In her eighty-ninth 

 year she revised some of her earlier mathematical manuscripts, which 

 had been forgotten for many years, and was surprised at the facility 

 she still retained for the calculus. One of her latest writings was the 

 acknowledgment of the receipt from Mr. Spottiswoode of a parcel of 

 recent advanced books upon the higher algebra, including quaternions. 

 In her ninety-second year, when she had written of the " Blue Peter 

 having long been flying at her foremast," and of her soon expecting 

 the signal for sailing, she was interesting herself in the phenomena of 

 volcanic eruptions, and speculating on their effects, and was following 

 with unabated interest the progress of scientific discovery and keeping 

 up with the record of events. She died in sleep. The list of scientific 

 societies of which Mrs. Somerville was a member, and of honors she 

 received, is a long one, and includes a number of American societies. 

 She also had among her personal friends many men of chief distinction 

 in American science and letters. 



During her later years Mrs. Somerville noted down some recollec- 

 tions of her life, and they, edited and supplemented by her daughter, 

 Martha Somerville, were published in 1873, under the title of "Per- 

 sonal Recollections, from Early Life to Old Age, of Mary Somerville." 



