PRACTICAL BOTANY 



*i6. Drawing-paper or card, with a hard smooth surface, or 

 a note-book of such paper, without lines. 

 *I7. Hard pencils (H. or H.H.H.) and india-rubber. 

 *i8. Gummed labels (i in. x fin.) for naming slides. 

 ^19. A coarse duster, and a finer cloth, e.g. an old pocket- 

 handkerchief. 



20. A rack for keeping slides temporarily, and a bell-glass 

 to cover it. 



*2I. A simple lens. 



*22. A compound microscope. This should be one of the 

 smaller stands with a short tube : such stands of varying merit 

 are to be obtained from most makers. The microscope should 

 be provided with 



*i. High and low eye-pieces : the longer is the lower 



power, the shorter the higher. 



*ii. Two objectives, the lower power of about 1 inch 

 focal length. The higher about one-sixth inch or 

 one-eighth inch focal length. 

 *iii. A micrometer, either adapted to the eye-piece, or a 



stage micrometer. 

 iv. A nose-piece to carry two, or, if necessary, more 



objectives : its use will save much time, 

 v. A camera lucida for drawing. 



*23. A rack or tray to hold small glass-stoppered bottles 

 containing reagents : the following are the reagents which are 

 in most constant use 



%. "Weak glycerine, i.e. Price's pure glycerine diluted 



with an equal volume of distilled water. 

 *b. Caustic potash : make a 2 per cent, solution of the solid 



sticks of caustic potash in distilled water, and filter. 

 *c. Acetic acid : one volume of glacial acetic acid is to be 



diluted with 99 volumes of distilled water. 

 *d. Iodine solution : this may be obtained by diluting the 

 liquor iodi of the Pharmacopoeia ; or as follows : 

 dissolve a small quantity of potassium iodide in 

 distilled water, and add crystals of iodine : if the 

 solution be too deeply coloured it may be diluted 

 with distilled water to the colour of brown sherry. 



