IgO MICROSCOPIC ILLUSTRATIONS. 



transit and circles, for then there is no loss of time when 

 yon wish to go to work, and you are sure to find every 

 thing just where you left it. I cannot be plagued by 

 eternally packing and unpacking my implements, &c. 

 but this is no rule for those who like such occupation. 

 Have caps to cover the objective and eye-glasses of your 

 instruments, and get a little nest of drawers to stand on 

 your table to keep talc sliders, &c. in, with a glass cover 

 or two (like those of watchmakers) to secure the more 

 delicate parts of your apparatus ; the rest will suffer no 

 harm from the dust. Procure a tripod stand, like those 

 used for small telescopes, and of such height, that when 

 you sit down and turn the body of your instrument 

 against the sky, like a telescope, the eye-piece may 

 present itself in a commodious position for observation. 

 You will also, probably, want a tripod stool to rest your 

 engiscope upon, when placed in a vertical posture for 

 dissecting and similar uses, as tables generally run too 

 high for the purpose, and are always more or less un- 

 steady. In towns the tremor occasioned by the transition 

 of carriages is frequently a great nuisance in the upper 

 stories of a house, more particularly if your mountings 

 are rickety and unstable. 



Now, courteous disciple, I will endeavour to instruct 

 thee how to manage thy tackle, and will, moreover, have 

 the extreme complaisance to suppose thee (in all micro- 

 scopic matters at least) one of the aivkward squad— as 

 stupid as an owl, and as ignorant as a cart-horse. I will 

 tell thee as well as I can all that thou art to do, and all 



