BOOK ?!.] INSTANCES OF THE DOOB. 517 



leads, by a regular fixed and well-established road, from the per 

 ceptions of the senses to those of the understanding (which are true 

 notions and axioms), it necessarily follows, that in proportion as the 

 representatives or ministerings of the senses are more abundant 

 and accurate, everything else must be more easv and successful. 



The first of these five sets of instances of the lamp, strengthen, 

 enlarge, and correct the immediate operations of the senses ; the 

 second reduce to the sphere of the senses such matters as are 

 beyond it ; the third indicate the continued process or series of 

 such things and motions, as for the most part are only observed 

 in their termination, or in periods ; the fourth supply the 

 absolute wants of the senses ; the fifth excite their attention and 

 observation, and at the same time limit the subtilty of things. 

 We will now proceed to speak of them singly. 



XXXIX. In the sixteenth rank, then, of prerogative instances, 

 we will place the instances of the door or gate, by which name 

 we designate such as assist the immediate action of the senses. It 

 is obvious, that sight holds the first rank among the senses, with 

 regard to information, for which reason we must seek principally 

 helps for that sense. These helps appear to be threefold, either to 

 enable it to perceive objects not naturally seen, or to see them from 

 a greater distance, or to see them more accurately and distinctly. 



We have an example of the first (not to speak of spectacles 

 and the like, which only correct and remove the infirmity of a 

 deficient sight, and therefore give no further information) in the 

 lately invented microscopes, which exhibit the latent and invi- 

 flible minutiae of substances, and their hidden formation and 

 motion, by wonderfully increasing their apparent magnitude. 

 By their assistance we behold with astonishment the accurate 

 form and outline of a flea, moss, and animalculae, as well as their 

 previously invisible colour and motion. It is said, also, that an. 

 apparently straight line, drawn with a pen or pencil, is dis 

 covered by such a microscope to be very uneven and curved, 

 because neither the motion of the hand, when assisted by a ruler, 

 nor the impression of ink or colour, are really regular, although 

 the irregularities are so minute as not to be perceptible without 

 the assistance of the microscope. Men have (as is usual in new 

 and wonderful discoveries) added a superstitious remark, that 

 the microscope sheds a lustre on the works of nature, and dis 

 honour on those of art, which only means that the tissue of 

 nature is much more delicate than tnat of art. For the micro 

 scope is only of use for minute objects, and Democritus, perhaps, 

 if he had seen it, would have exulted in the thought of a means 

 being discovered for seeing his atom, which he affirmed to be 

 entirely invisible. But the inadequacy of these microscopes, for 

 the observation of any but the most minute bodies, and even of 

 those if parts of a larger body, destroys their utility ; for if the 



