THE COMPOUND MICROSCOPE 17 



improved definition. Lenses and diaphragms were 

 held in position by cardboard collars (blackened) 

 glued inside the Mttle tubes. The one eye-piece I 

 made consisted of a tube made to sUp into the 

 opposite end of the body ; it was about 2 inches 

 long, and contained two plano-convex lenses, one 

 at each end, with their convex faces turned down- 

 wards. It also had a diaphragm, with a f-inch 

 aperture, placed in the tube midway between the 

 lenses. The end of the eye-piece nearest the eye 

 was capped with the rim sawn off a cotton-reel, its 

 aperture being enlarged to f inch. 



The body tube was made to slide in another 

 short tube for focussing purposes, and the rest of 

 the stand, including the stage, was of wood, the 

 stage being worked out of a cigar-box hd. The 

 stage springs for holding the mounted objects in 

 position were pieces of watch-springs. The mirror 

 was a circular one, with plane surface, which, I 

 think, cost 2d., and was suitably fixed below the stage. 



A double convex lens, it should be explamed, is 

 one that bulges on both sides ; a plano-convex lens 

 bulges on one side and is flat on the other. My 

 objective lenses cost me nothing, as they were ob- 

 tained from an old triple pocket magnifier with 

 broken mount which was discovered in the house. 

 My eye-piece lenses were got from an optician out 

 of old stock at about a shilling. I understand that 

 Messrs. J. Lancaster and Sous, Ltd., Birmingham, 

 supply a set of lenses and accessories for use of 

 amateur microscope-makers . 



While such a home-made microscope can be made 

 use of when a better instrument is not available, 



