z- 4 THE MICROSCOPE. 



of one, lay it clown and take up another. Strange as this may 

 appear, it is quite a cure for impatience, and besides, more progress 

 may be made with a dozen, than by working with one specimen 

 only at a time. 



I may say here that in making sections of flints, agates, and 

 stones of like hardness, it is of no use rubbing them on the sand- 

 stone; they must be ground down from the very first on the iron 

 plates with emery. The rest of the process is the same as has been 

 described above. 



I fancy that diamond-dust would be the disintegrator par excel- 

 lence, but have never indulged in this luxury. 



When the specimen is thin enough, and the beech can be well 

 seen through it, I give it a few light rubs on the Water-of-Ayr stone, 

 using water. The specimen can then be taken off the wood and 

 mounted in Canada balsam, under a thin cover glass. 



Remove with a wet cloth all the gum from the edge of the 

 specimen,, and thoroughly clean the wood of all impurity. Boil the 

 kettle. Stick the blade of a pen-knife into the side of the beech, to 

 act as a handle, and hold the specimen in the steam from the ket- 

 tle-spout till it condescends to slide down the face of the wood. 

 There need be no fear of its falling off. The water from the steam 

 will prevent this. It may come off in less than five minutes, or it 

 may take half an hour. Do not get impatient. To beguile the 

 time, you may theorize about the size and number of the imaginary 

 spaces that intervene between the molecules, or atoms, that build 

 up the lock, and the size of the water molecules which are trying to 

 find their way through these spaces in order to dissolve the gum 

 arabic fixing the specimen to the wood. If the specimen take a 

 long time to come off. you are very apt to conclude that the water 

 "molecules" are too large to find their way through these spaces, 

 and that they are laboriously "working their passage" underneath 

 the specimen. Do not try to hasten the process by "nudging" the 

 specimen with the edge of the knife-blade; this will only end in a 

 vexatious smash. You mast wait. After all, on an average, about 

 a dozen specimens can be "steamed" from the wood and mounted 

 in balsam, in about two hours. With every care, a specimen will 

 sometimes break in two or more pieces, but you must just take 

 advantage of this "multiplication by division," and make a slide of 

 ea< h fragment. The specimen having at last become loose on the 



