THE AMERICAN BOTANIST 25 



led case ?.nd costs $1.50 and upwards. The same effect as well 

 as higher powers is secured in more expensive instruments, by 

 the use of two lenses, one in each end of the frame or case and 

 frequently these lenses may consist of two different pieces of 

 glass cemented together. The price now depends in great 

 measure on the mountings of the lenses. Those in which the 

 lenses have no mountings of their own but are merely held in 

 position by other parts of the case cost from fifty to eighty 

 cents; other in which the lenses are set in frames that are re- 

 movable for cleaning cast a dollar and upwards. The very ex- 

 pensive lenses running upward to ten dollars are expensive 

 principally because of finer workmanship and clearer lenses.The 

 magnifying power does not increase in proportion to the cost. 

 At the other extreme, one may secure pretty good results with 

 a drop of water and a bit of window glass, if the glass is held 

 horizontally with the water drop on the under side. More per- 

 manent microscopes of fair usefulness may be made by mount- 

 ing a bead of glass in a metal plate. It is this kind of an in- 

 strument that street fakirs are fond of selling the public at a 

 good price. It is, however, the type of the first microscopes 

 and it was an instrument exactly like this that Leeuenhoek and 

 Grow saw the first plant cells ever known. 



Leaf Prints. — In the primary grades pupils are fre- 

 quently taught to make blue and other prints of various wild- 

 flowers which are subsequently mounted in books. Often, how- 

 lever, the prints fail to show much detail and the best results 

 are not attained. If the teacher would confine these prints to 

 the leaves of trees there would rarely be a failure and in the end 

 the pupil would have a book of practical value provided the 

 names of the trees were given. 



