216 The Microscope. 



tion. This desirability is conceded. But at once there arises an 

 obstacle ; in fact there are three of these obnoxious things. The 

 ordinary instrument is usually too large and heavy to be taken, 

 and for this reason is often perforce left at home. There is no 

 entirely commendable travelling stand in the American market. 

 Some of our opticians should make one at a reasonable cost, if 

 such a thing is possible. Mr Zentmayer's Pocket Stand is magnifi- 

 cent ; it is perfect, but its perfection puts it beyond the reach of 

 any but the wealthy microscopists, of whom there are few. Mr 

 Zentmayer has a Portable Histological stand, but aside from the 

 cost, it is too large for the present purpose. 



The ideal instrument will be light in weight, a thing not incom- 

 patible with steadiness and stability. The body tube will be 

 large enough to receive the largest eye-piece made by any repu- 

 table optician in the world. It will be sold without oculars, so 

 that the purchaser of this summer instrument can use his own 

 eye-pieces. If they shall be too small to fit properly, any one 

 can bandage them with a strip of paper and a little mucilage, 

 making a cylinder that when dry will be almost as hard and 

 firm as a wooden one. The body at that end will thus be adapted 

 to all ordinary demands. At the other there will be the society 

 screw. This goes without saying. The coarse adjustment should 

 be by rack and pinion ; if necessary to save expense and weight, 

 the milled head on the left hand side may be omitted. The fine 

 adjustment should be at the back of the arm, and no graduations 

 would be needed on any part, as vacation work will not deal 

 with the measurement of thin glass, the working distance of high 

 power objectives, the angles of crystals or of aperture. The 

 vacation microscopist will be seeking recreation and amusement, 

 the one for himself, the latter for his friends at the shore and 

 among the mountains. There must of course be a joint for in- 

 clination, as the microscopist is now struggling with a weary 

 back, and will not care to own anything so burdensome as an 

 invertebrate stand. 



As the ideal travelling stand will be portable with its case, it 

 might dispense with a special foot and be screwed into the top 

 of its box, as Mr Zentmayer's Pocket Stand is arranged. This 

 would increase the lightness and decrease the cost. 



The stage should be of the simplest form. It needs only 

 spring clips to hold the slide in position. But will the maker 



