( 218 ) 



I alfo make a hollow, as at K L, to embrace the glafs tube, and hav- 

 ing drilled two holes in it at A B, to correfpond with the two holes 

 Q R, in fg. 2, I place it on the contrary fide of the plate, fg 2, 

 and rivet it with two brafs rivets through the holes Q R. 



I then prepare another piece of brafs more than twice the thick- 

 nefs of the former, to be fcrewed clofe to the plate, fg. 2, and to 

 which the microfcope is to be fixed ; this piece of brafs is repre- 

 fented at fg. 5, NOPQRST, and in this I drill two holes to 

 correfpond with thofe at O and N in fg 2 ; thefe holes, V and W, 

 are made to receive fci-ews in them, in order to fix by them the 

 plate, ^g'. 5, to the plate, fg. 2. In this piece of brafs, I alfo drill 

 a third hole with a fcrew fitted to it, by which the magnifier may 

 be adjufted at a proper diftance, which hole is fliewn at X. I 

 make likewife in this piece of brafs a fourth hole, rather larger than 

 the former, in order that the magnifier, when adjulled by the fcrew, 

 may be moved to the one fide or the other : lallly, I bend this piece 

 of brafs, at the place marked with the dotted line PR, to a right 

 angle. 



I then make three fcrews, one of which is fhewn at A B, fg. 6, 

 and with two of them I fcrew the brafs, fg. 5, to the plate, fg. 2, 

 paffing one fcrew through the hole O, ^^g- 2, and V, fg. 5, and the 

 other through the holes N, fg. 2, and W, fg. 5 : the third fcrew 

 is to fix the magnifier by the hole Q, to the piece of brafs, fg. 5 . 

 I alfo make a fourth fcrew, as at fg. 7, CD ; the only ufe of 

 which is, that, being pafled through the hole X, in Jig. 5, it may 

 ferve to fix the magnifier at a proper difiance from the objed to be 

 viewed. 



Fig. 8, E FGH T, are two thin plates of brafs or filver joined 

 with five rivets, between which the magnifying glafs is placed at 

 Iv ; and at K is fliewn a hole made to receive a fcrew, by which 

 the magnifier is fixed to the brafs inftrument before defcribed. 



1 have alfo caufed a drawing to be made of the whole inftrument, 

 as viewed on one fide, (before the magnifying glafs is joined to it). 



