308 SCIENTIFIC THOUGHT. 



not as clear as it has become since, and the work has 

 also been superseded by more detailed labours, espe- 

 cially of German historians. 1 The ' Philosophy of the In- 

 ductive Sciences/ by the same author, was written with 

 the object of doing something towards determining the 

 nature and conditions of human knowledge, and had 

 thus a philosophical rather than a historical object in 

 view. The same can be said of Mill's ' Logic,' of Conite's 

 ' Philosophic positive,' and of more recent works such 

 as Jevons's c Principles of Science.' They form an im- 

 portant section of the philosophical literature of our 

 century, and on future occasions I shall frequently have 

 to refer to their teaching. At present I am not about 

 to investigate the eternal principles of correct reason- 

 ing, and the particular methods adopted, consciously or 

 unconsciously, by scientific writers of all times. "What 

 I desire to do is, to enumerate and analyse briefly the 

 changing ideas, the general views, under the guidance 

 of which scientific work has progressed in the course 

 of this century. No doubt the same object was before 



1 Besides the works on the his- j of the ' Theory of Attraction and 

 tory of the special sciences con- Figure of the Earth' (2 vols., 



tained in the Munich Collection, 

 ' Geschichte der Wissenschaf ten in 

 Deutschland,' which in many in- 

 stances is not limited to German 

 science and learning, there is the 

 unique ' Geschichte der Chemie,' 

 by Hermann Kopp (Braunschweig, 

 4 vols., 1843-47), the ' Geschichte 

 der Physik, 1 by Rosenberger (Braun- 



1873), the ' Calculus of Variations ' 

 (1861), the 'Theory of Probability' 

 (1865), and the 'Theory of Elastic- 

 ity' (continued by K. Pearson, 2 

 vols. in 3 parts, 1886-93). They 

 supply the want of a good history 

 of modern mathematics, which does 

 not exist. Lastly, the " Deutsche 

 Matheniatiker- Vereinigung " have 



schweig, 3 vols., 1882-90), and i published in their Jahrbuch valu- 



Haser's ' Geschichte der Medicin ' | able histories of special branches of 



(Wien, 1875-82, 3rd ed.) In addi- ! mathematics notably the ' Theory 



tion to the numerous works of Ger- j of Invariants ! by Franz Mayer, and 



man specialists, I must mention as of I the ' Modern Theory of Functions ' 



the first importance and value the i by Brill and Xoether. 



histories by the late Isaac Todhunter I 



