8 APPARATUS AND METHODS. 



Great care is necessary in using the high power, since the 

 objective when in focus is so close to the object. Do not 

 let the high objective touch the slide, and above all do not 

 go on ramming or racking the tube down after passing the 

 position of focus, or you may ruin the objective, besides 

 breaking cover-glass and slide and damaging the specimen. 

 Always use a cover-glass with the high objective ; if you 

 cannot see anything clearly, stop at once, move the tube 

 upwards, wipe the objective, remount the specimen (if 

 examined in a drop of water, which is liable to flow over 

 the cover-glass and wet the objective), clean the cover-glass, 

 and start again. If glycerine or other mounting fluid or 

 reagent gets on the objective, wipe the latter with a cloth 

 wetted with water, then dry it thoroughly. 



Keep both eyes open when using the microscope ; this 

 lessens the fatigue of microscope work, and is not at all 

 difficult if you practise for a few minutes each time you 

 start work. Accustom yourself to using either eye indif- 

 ferently. 



7. Accessories for Microscope Work. The following articles 

 are necessary for work with the microscope : 



(1) A few dozen glass slips, 3 in. x 1 in. 



(2) An ounce of J in. square cover-glasses, No. 2 thickness. 



(3) A pair of fine-pointed forceps. 



(4) A pair of fine scissors with sharp points. 



(5) A few camel-hair brushes. 



(6) A few mounted needles ; these can be made by fixing a 

 needle, by means of pincers, into one end of a pen-holder, or 

 a handle adjustable for any needle can be bought for about 9d. 



(7) A few flat-bottomed watch-glasses. 



(8) A few ointment pots with lids. 



(9) A small spirit-lamp, about 4 ounce size. 



(10) A coarse duster, a finer cloth (e.g. an old but clean 

 handkerchief), and a small chamois leather the last to be 

 kept for cleaning up the microscope only. 



(11) Small reagent bottles with dropping-rods, one for 

 each of the reagents most commonly used, e.g. (a) glycerine 

 diluted with equal volume of water, (6) a 5 per cent, solution 

 of caustic potash in water, (c) iodine solution, (d) aniline 

 sulphate solution, (e) a 5 per cent, solution of common salt, 

 (/) chlor-zinc-iodine. 



