572 SPECIAL METHODS OF DISCOVERY. 



the existence of fluids under a state of great pressure in 

 stones, which caused the.latter to explode whilst being cut. 



6. By employing new or improved modes or instru- 

 ments of observation. The method of making discoveries 

 by means of the invention and employment of a new or 

 improved mode of observation, is a very varied and ex- 

 tensive one, and has proved one of the most fruitful. 

 It includes a number of more special ones : for instance, 

 by using a new instrument of observation ; by employing 

 a known instrument in a new way ; by using instruments 

 of increased power or magnitude ; by employment of im- 

 proved, more exact, or more delicate instruments. Pro- 

 bably more discoveries have been made by means of this, 

 than by any other equally special method, because it is 

 highly adapted to several of the chief laws of discovery. 

 A new mode of observation agrees with one of those laws 1 

 by enabling us to perceive matter and its phenomena in 

 a new aspect ; and as many of the phenomena of bodies 

 are such as cannot be perceived at all by our unaided senses, 

 the employment of a new or more delicate apparatus or 

 mode of observing usually enables us to notice what we 

 could not previously detect. 



Every new mode or instrument of observation, and 

 every improvement in scientific apparatus, is almost in- 

 variably quickly followed by new discoveries. With every 

 addition to the power of telescopes, more and more distant 

 worlds have been discovered, and an increased number of 

 supposed nebulae have been found to be composed of 

 numerous points of light. The use of microscopes of 

 increased magnifying power and definition, has always 

 been attended by discoveries of structures or markings 

 still more minute ; that of spectroscopes of increased 

 dispersive power has also led to the discovery of a greater 

 1 Seep. 458. 



