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Microscopic At Essays, 



S, a camel's hair pencil to brufh the dufl: off the glaffes ; the 

 upper part of the quill is fcooped out, to take up a drop of any 

 fluid, and place it on either of the glaffes for examination. 



T, an instrument for cutting thin tranfverfe feftions of wood. 

 It confifts of a wooden bafe, which fup ports four brafs pillars ; on 

 the top of the pillars is placed a flat piece of brafs, near the mid* 

 die of which there is a triangular hole. 



A fharp knife, which moves in a diagonal direction, is fixed on 

 the upper fide of the afore mentioned plate, and in fuch a man- 

 ner, that the edge always coincides with the furface thereof. 



The knife is moved backwards and forwards by means of the 

 handle a. The piece of wood is placed in the triangular trough 

 which is under the brafs plate, and is to be kept fteady therein, 

 by a milled fcrew which is fitted to the trough ; the wood is to 

 be preffed forward for cutting, by the micrometer fcrew b. . 



The pieces of wood mould be applied to this inftrument im- 

 mediately on being taken out of the ground, or elfe they mould 

 be foaked for fome time in water, to foften them fo that they may 

 not hurt the edge of the knife. 



When the edge of the knife is brought in contaa with the 

 piece of wood, a fmall quantity of fpirits of wine mould be pour- 

 ed on the furface of the wood, to prevent it's curling up ; it will 

 alfo make it adhere to the knife, from which it may be removed: 

 by preffmg a piece of blotting-paper on it, 



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