190 MEMOIR OF GEORGE WILSON. CHAP. VIIL 



precision, width of view, and philosophic eloquence, which 

 reminds us of Playfair, and in which the whole question of 

 Dalton's merit as a discoverer is, through original research, 

 placed in a new point of view, by tracing the independent 

 and altogether peculiar course of inquiry by which he was 

 led to his atomic hypothesis." " ' The Life and Discoveries 

 of Dalton,' one of the greatest of English chemists, is treated 

 with a learned appreciation of the subject. It is one of 

 those delightful essays which serve to open the lights of 

 science upon the uninitiated, without dazzling them, or de- 

 terring them with too abstruse details." 



His " Text-Book of Chemistry," which forms one of the 

 volumes of " Chambers's Educational Course," was written 

 to dictation in the summer of 1849, in the " Sleepy Hollow" 

 of Morningside. Rheumatism was an unfailing visitor in 

 summer, frequently affecting the arms to a painful extent. 

 In that year it compelled the abandonment of spring 

 classes, and this Text-book was undertaken as the only work 

 of which he was capable at the time, idleness being to him 

 an impossibility. He was quite unable to hold a pen for 

 months, and dictated its pages to a sister while pacing the 

 room with compressed lips, that showed the pain could 

 scarcely be endured ; but pain never stopped work, and the 

 success of the book has been such as to repay the effort 

 abundantly. Its sale has been at the rate of 2,500 copies 

 yearly, and upwards of 24,000 copies, in all, were sold in 

 the nine years immediately following its publication. It 

 has been recommended, by the Council of the Society of 

 Arts, London, to the students preparing for examination for 

 its certificate of proficiency, and has met with general ac- 

 ceptance. It is thus noticed in periodicals of the day: 

 " There are few books on chemical science in our language 

 which so fully explain its leading features. . . . His little 



