198 The Microscope. 



that objects may be viewed, from the size of a large beetle or 

 moth to the most minute animalcule. These powers are marked 

 Nos. 4, 5, 6; No. 4 is the lowest power, and is calculated for 

 viewing opaque and large objects, and should be used without the 

 body; No. 5 is the next power, and is calculated for viewing all 

 the objects of the size of those in the slides; the next power is 

 produced by combining the Nos. 4 and 5 together, which may 

 be called the third power; it magnifies twenty-five hundred times, 

 and is adapted for viewing the animalcules, ^c. The greater 

 power is in a conical cell, marked No. 6; with this power an ob- 

 ject is magnified twenty-six thousand times with the body, which 

 is equal to the largest compound microscopes ; it should only be 

 used for extreme minute objects, and without either of the other 

 powers: as the object and the lens come extremely near when it 

 is used, care must be taken, by a very deHcate movement of the 

 stage, that they do not come in contact with each other in getting 

 the proper focus. To prevent this, if a drop of water is to be 

 examined, place it between the shps of glass, and if these will 

 not admit the lens to come near enough, place a piece of thin talc 

 upon it. Objects should first be viewed with the low j^Dwers, 

 that the whole of them may be seen, and the highest ones caa 

 then be used in gradation. 



Objects for the Microscope. In the summer months, 

 the waters, as well as the hedges, abound with living wonders for 

 the Microscope, and afford an endless amusement to the admir-* 

 ers of the works of nature in the minute creation. 



Best Method of procuring Aquatic Insects. In the 



ponds and ditches that are covered with duck-weed, surprising 

 insects may be found: some of this weed should be procured, 

 and put into a white earthen vessel; it will be a never-failing sup- 

 ply of living, and most entertaining objects for the microscope, 

 and may be kept the whole of the winter months, as the leaves 

 have the valuable property of keeping the water fresh. Every 

 proprietor of a microscope, who would wish to secure a supply 

 of a great variety of interesting Hving objects in constant readi- 

 ness, should adopt this method of obtaining them. The decayed 

 leaves will be found best for the purpose; two or three of these 

 being taken out, with a small portion of water, on a piece of glass, 

 gently press them, and the wheel animal, as well as many others, 

 will come out from the cells in which they have taken up their 

 abode. The bell-shaped polype, the proteus, and other smaller 

 kinds of animalcules, may thus be had in great numbers. 



