86 6IOIIT. 



the senses are flood-gates, in which there are always 

 currents when they are open, and if new knowledge 

 does not flow in, time will flow out, and bear off our 

 old knowledge on its tide. There is no means of 

 avoiding the last of these but by pursuing the first ; 

 and thus observation is really our guardian, as well 

 as our guide. In our business or profession, how 

 much soever we are occupied with it, it is impossible 

 to get as much observation as will keep all the 

 senses up to their proper tone ; and therefore the 

 observation of nature comes in, not to draw us away 

 from our callings, but really to work along with us 

 and encourage us, as a most ready-handed and gay- 

 hearted auxiliary. 



There remains only one sense to be noticed, 

 and that is the sense of sight a sense, the organs 

 of which in their structure more resemble con- 

 trivances that we can make than those of any of 

 the other senses. On that account we can assist 

 and improve our eyes more by artificial helps than 

 we can any of our other sensal organs. If the sight 

 is too short, we can lengthen it by spectacles hollow 

 in the middle ; and if it be too long, we can shorten 

 it by spectacles of the opposite form ; so also we 

 can make distant objects appear near with the tele- 

 scope, and small ones appear large with the micro- 

 scope. These are very useful contrivances ; but 

 the use of them is limited to a small number of people, 

 and not a great number of occasions. When we go 

 out to recruit ourselves by the popular observation 

 of nature, we are not to carry spectacles, telescopes, 

 and microscopes with us, but to use our own eyes ; 

 and to nine hundred and ninety-nine in every thou- 

 sand of us, well-educated eyes, used to good pur- 

 pose, are superior to all the philosophical instru- 

 ments in the world. Those instruments are valuable 

 to such as require them, just as the tools of every 

 trade are useful to those who follow that trade ; and 

 improving the tool is the best and most certain way 



