22 GENERAL VIEW AND BASIS OF SCIENTIFIC RESEARCH. 



The future limits of human knowledge seem to be in- 

 finitely distant ; the exertion of creative power in develop- 

 ing and improving mankind appears to be infinitely far 

 from being exhausted. It is highly probable that there 

 remains to be discovered a vast number of scientific truths, 

 of which we are at present totally ignorant, because very 

 large gaps are evident in all directions in our present' 

 system of knowledge ; and because we now know multi- 

 tudes of substances, actions, and conditions and relations 

 of bodies with which we were formerly unacquainted, and 

 the number is rapidly increasing. It is only since the use 

 of telescopes that numerous distant heavenly bodies, and 

 various phenomena relating to them, have been known to 

 exist, which must have had being during countless previous 

 ages : the moons of Jupiter and of Mars, for example. 

 Various substances now known by means of the spectro- 

 scope to be in the sun and other stars, were doubtless in 

 those heavenly bodies during all their past duration. The 

 microscope has revealed to us an almost infinite number 

 of minute organisms and structures, of which the ancients 

 were totally ignorant. In like manner chemical analysis 

 and synthesis have made known to us an immense number 

 of new substances, simple and compound, not before known, 

 and enabled us to produce many that had no previous 

 existence. By means of modern discoveries in the sciences 

 of heat, electricity, and magnetism, we have learned that 

 a multitude of changes occur in the interior of substances, 

 when the latter are moved or altered in temperature. The 

 use of polarised light has also disclosed to us in transparent 

 bodies a great number of peculiar internal structural con- 

 ditions of which we were previously ignorant. All the 

 properties and actions of matter and its forces are inti- 

 mately related to the molecular structures and motions 

 existing in bodies, and these structures and motions are 



