166 ON THE CHOICE OF A MICROSCOPE. 
scopes, as they necessarily form by far the largest class of pur- 
chasers. Those, then, who, for the preceding reasons, do not 
aspire to the possession of first-class instruments, but such as 
rank midway between the most and the least expensive, will 
find all that they can desire in great variety at any of our prin- 
cipal makers, called students’, medical or educational micro-. 
scopes, and by Mr. Ross, “the bases of complete instru- 
ments.” These microscopes are of a very high order, both 
as regards the mechanical and the optical parts. They are 
generally furnished with two best object-glasses, and all neces- 
sary apparatus, at a cost varying from £20 to £40. And I 
must here beg to reiterate the advice already given with respect 
to first-class instruments. It is better, having secured the 
object-glasses, to purchase at once the most complete mi- 
croscope stand, with its usual appliances that the highest 
price here mentioned will procure. It is far better than 
having additions made to it on some future occasion, which 
may necessitate the return of the instrument to the maker, 
and by far the cheapest plan in the long run. For those, 
again, who are restricted to the least expensive form of 
microscopes, the market now-a-days is happily as extensive 
and fruitful as it is excellent. I would recommend such 
persons to procure a catalogue of microscopes from Messrs. 
Smith and Beck, or Mr. Pillischer, or, indeed, any of 
the opticians whose names are given below, and where they 
will find the description of a class of instruments called uni- 
versal, or hospital, small students’ or third-class educational, 
which have useful mechanical movements and object-glasses 
at the moderate cost of from £5 to £15. 
I have often thought how fortunate I should have considered 
myself, when a boy, could I have bought for £10 sucha 
microscope as Messrs. Smith and Beck, or Mr. Pillischer, 
now offer to the public at £5. The price, indeed, of the 
instrument by Mr. Field, of Birmingham, with similar 
apparatus to the above, and for the satisfactory working of 
which I can vouch myself, is as low as £3. 
Such microscopes, though with eye-pieces and all neces- 
sary appliances to the stand, are, of course, in their most 
simple forms, and are rather suited for instruction and amuse- 
ment than for scientific research ; nor would it be reasonable 
to expect from them what can only be found in far higher- 
priced instruments. But those which run as high as £15 
are provided with the binocular arrangement, fine and coarse 
adjustments to the optical part, moveable stage, parabolic 
reflector, polariscope, and all necessary apparatus, with such 
object-glasses as are usually supplied with these instruments ; 
