CHAPTER XIX. 



LABORATORY EQUIPMENT. 



236. Tables. — In a school where the study of plants is to be 

 seriously pursued there should be a working room equipped with tables 

 of such size, and so arranged, as to give the students plenty of room 

 and light for their work. The ordinary school desks are not of suitable 

 construction and arrangement for laboratory work, and where a special 

 laboratory cannot be provided, it would be a good plan to fasten boards, 

 about eighteen inches wide, to th^ wall beneath the windows, by means 

 of strong brackets, to serve as working tables. Even where there is a 

 special workroom, such tables will be found very serviceable. The 

 main thing in any case is to have a flat working table, well lighted by 

 diffuse light, which will afford plenty of elbow room for each student. 



237. Microscopes. — Much of the obser\'ation in an introductory 

 course in botany can be done with the naked eye, but for part of the 

 work a good simple lens is a neces- 

 sity.^ It is economical to have cheap 

 pine blocks made as stands for the 

 lenses, after the manner of Fig. ig6, 

 rather than to purchase the stands 

 of the dealers. Ordinary 2 by 4 inch 

 pine scanthng is dressed smooth, 

 and cut into two lengths of 8 and 3 

 inches respectively. It is better to 

 bevel the ends of the short pieces. 

 The short piece (3) is to be fastened 

 to the long piece (a), as shown in 

 Fig. I, by means of glue and a screw 

 driven through from the lower face 

 of the long piece. A brass rod (c) about y\ inch in diameter and 3^ 

 inches long is driven into the short block, as seen in the figure, to a 



1 The doublet lenses manufactured by Bausch & Lomb, Rochester, N.Y., 

 are satisfactory for this purpose, those of |-inch focal length being the best 

 for general work. 



371 



Fig. 196. 



A simple dissecting microscope. 

 See text. 



