4) 



On an Instrument for Cleaning Thin Covering Glass. 

 By W. W. Jones. 

 (Read April 23, 1875.) 



A very common complaint amongst working Microscopists is of 

 the trouble they have in cleaning very thin glass covers without 

 breaking them ; in fact, I know that with many the annoyance is 

 so great that they use the thicker glass for all specimens, and so 

 render them utterly useless for examination with high powers. 

 Now, I think you will hold with me when I say that nearly if not 

 all transparent specimens would be of infinitely greater value if 

 they were capable of being examined with the higher powers, and 

 as the thinnest glass is just as cheap as the thick when you 

 consider that you get about twice the number to the ounce, the 

 only drawback to its more general use that I can see is the great 

 breakage that occurs in cleaning, to obviate which I wish to bring 

 before your notice a small and simple apparatus, which I find 

 answers exceedingly well, having used it for the last 12 or 18 

 months. It consists of a small tube of brass or steel, of about an 

 inch in diameter and the same in height, into which fits loosely a 

 weighted plug. To the lower end of this plug is cemented a piece 

 of chamois leather. Another piece of leather is stretched upon a 

 flat piece of wood or plate glass to form a pad, which completes the 

 apparatus. ' 



The mode of using it is this. You place the tube on the pad, 

 breathe on the glass, drop it into the tube, put in the plug, and 

 then holding the tube well down on the pad you can rub as much 

 as you like with perfect safety, the weight of the plug giving 

 sufficient pressure. With this simple arrangement you will find it 

 almost as difficult to break the glass as many have hitherto found 

 it easy. I hope that this may be the means, not only of saving 

 time and trouble, but also of adding materially to the value of 

 many good specimens which are now often half spoilt by the use of 

 thick covers. 



