114 Dr. Goring on ihe new Microscopes^ ^C, 



therefore, ever remain of the highest value; for it will be 

 recollected that if their forte does not extend beyond powers 

 ranging as far as the J^ inch, that in this scale all the 

 working powers are included. The deepest single lens among 

 those employed by Leeuenhoek, was of no shorter focus, 

 and with this he saw more than ever was seen before his 

 time, or ever will be seen again, with all our boasted im- 

 provements. 



When we come to powers exceeding the -^jj inch, the single 

 miscroscope comes into full effect, and carries us on till all 

 certain vision fades away into obscurity, and the strain upon the 

 eye in finding the object and adjusting the focus becomes no 

 longer tolerable: there can be no doubt that powers of ^\y and ^^ 

 inch (to the use of which the eye may be familiarized) enable 

 us to look more closely, more narrowly, more deeply, and more 

 certainly, into the texture of highly-finished objects, than any 

 equal powers of the compounds. 



It may not be taken amiss if I here give my advice concern- 

 ing the particular sort of microscope best adapted for any given 

 purpose ; for, as I have been the main agitator by whose in- 

 fluence and exertions the new microscopes have been brought 

 into use, I cannot be suspected of undue partiality towards 

 any of them. First, then, is your purpose merely amusement 

 for yourself and friends, without having any particular object 

 in view ? Will you be content to see what has been seen 

 before your time, without attempting to discover any thing 

 yourself, or to rectify the discoveries of others ? get an achro- 

 matic, and view large objects mth. low powers; two object- 

 glasses, one of two inches focus, and another of one inch, will 

 be quite sufficient. Any attempt to show small difficult objects 

 with high powers, to individuals unused to microscopes, is sure 

 to miscarry. The peripatetic microscopists in the streets, 

 and public exhibitors, know this full well ; they always show 

 large objects with low powers, and then put their disciples into 

 extacies, by telling them that they are looking at very minute 

 objects with very high powers. The o7 ttoXKoi moreover are 

 never pleased unless they can see the ivhole of their object ; 

 they must likewise have every mathematical point about it in 

 the focus at once, no matter how uneven or irregular it way be. 



