272 PERSONAL PREPARATION FOR RESEARCH. 



facturers, or analyses for commercial purposes, is less in- 

 harmonious, because in the intervals of the processes a 

 research may be sometimes advanced ; but when those 

 investigations or analyses are numerous, they by their 

 multiplicity of operations and processes prevent all other 

 experiments being made. 



Although wealth is not generally necessary to research, 

 a moderate competency is essential for long-continued 

 investigation. Experiments cost money and require much 

 time, and few men can long pursue difficult investigations 

 with the cares and anxieties of life pressing upon them. 

 Cavendish was a very wealthy man, and also a great in- 

 vestigator, but he neglected attending to his wealth, pro- 

 bably because he preferred to attend to research. Scheele 

 was comparatively poor, yet he made a greater number of 

 chemical discoveries, at an early age, than alrrost any 

 man ; he was, however, unmarried, and without the cares 

 of a family. He had the advantage of having been a 

 pupil of Bergmann, and was encouraged in his pursuits by 

 Prince Henry of Prussia and by the Duke of Sudermannia ; 

 he was also extremely industrious, and of a strictly logical 

 habit of mind. In addition to freedom from anxiety and 

 pecuniary care, a large amount of quiet leisure is almost 

 indispensable, and those who cannot obtain this cannot 

 make many discoveries. Priestley made numerous experi- 

 ments, his occupation as a Unitarian preacher afforded 

 him the time, and his friends and admirers found him a 

 sufficient supply of money. 



In consequence of the large amount of time necessary 

 for research, those scientific men who devote themselves 

 largely to the more remunerative occupations of pursuing 

 a scientific art or trade, making investigations for manu- 

 facturers or public companies, developing inventions or 

 patents, making chemical analyses for commercial pur- 



