234 MEMORANDA. 



Cheap Microscopes. — The President of the Microscopical 

 Society in his late address drew attention to the general im- 

 pression, that in order to make good observations it was 

 necessary to have a high-priced microscope. He denied this, 

 and stated his conviction that all the arrangements necessary 

 for accurate investigation might be obtained at a very much 

 lower price, than is given for the very perfect and beautiful 

 apparatus of our first makers. The drawback on purchasing 

 cheap microscopes is the want of knowledge of the properties 

 of good glasses on the part of beginners. As the use of the 

 microscope is now becoming a matter of educational import- 

 ance, and as in order that it may be used by all, it must be sold 

 at a price to be attained by all and at the same time a good 

 instrument insured, the Society of Arts has offered two prizes 

 for the best microscopes at stated prices. We have much 

 pleasure in drawing attention to the following announcement 

 of this Society. The Council has determined to offer special 

 prizes — 



1. For a School Microscope, to be sold to the public at a 

 price not exceeding 10s. Q>d. — Prize — The Society s Medal. 



To be a simple microscope, furnished with powers as low 

 as those of a pocket-magnifier, for the purpose of observing 

 flowers, insects, &c., without dissection. The lenses should 

 range from two inches to l-8th of an inch ; the focal adjust- 

 ment to be by rack-work, extending sufficiently above the 

 stage to allow a thick object to be brought under the lowest 

 power. It should be furnished with plyers, a concave mirror, 

 and an illuminating lens, also a live box, or, instead of it, two 

 or three glass cells of difterent depths, a few slips of common 

 glass, and a few pieces of thin glass for covers. 



Makers are requested to state at what additional price 

 they will undertake to supply a doublet of 1-1 6th or l-20th 

 of an inch, applicable to any instrument as above described. 



2. For a Teacher s or Student's Microscoj/e, to be sold to 

 the public at a price not exceeding 3/. 3^. — Prize — The 

 Society's Medal. 



To be a compound Achromatic Microscope, with two eye- 

 pieces and two object-glasses, one magnifying 120 diameters 

 with the lower eye-piece, the other magnifying 25 diameters 

 with the lower eye-piece. It should be furnished with a dia- 

 phragm, having various-sized openings, mirror, side illumi- 

 nator, live box, forceps stage and case. 



In the event of the medal being awarded, the Council is 

 prepared to take 100 of the smaller and 50 of the larger micro- 

 scopes, at the trade discount. 



