597 
Dr, knight’s Magnetic al Machine . 
9 • ^ • s . * . ~ * • f '**'_**• 
• ^ -» * > ji, - • • / * 4 “»■ 
\ 
EXPLANATION OF THE PLATE. 
Plate vii. fhews the magazines according to thedodor’s 
laft difpofition of them. The two being perfectly alike, 
therefore fig. 2. contains only the half of one of them. 
Each magazine confifts of 240 bars, difpofed in four 
lengths, marked 1. 2. 3. 4.; every length containing 
fixty bars, placed in fix courfes or layers, in contact one 
on another ; and ten in each courfe, placed fide by fide, 
in contact alfo. The bars being very nearly of a fize, 
the ends of thofe in one length are in contad with the 
correfponding ends of thofe in the adjacent lengths. 
The. magnetical North-ends of thefe bars, in each maga- 
zine, are all directed one way towards n ; and the South- 
ends the contrary way toward s ; thick plates of iron 
cover theie ends N and s ; the junction of the ends of the 
bars fall under the brais braces a a. 
As it has been found difficult, after the final harden- 
ing of thefe bars, to prelerve among them a perfect 
equality in fize; therefore, the contact of their fides are 
perfected by thin iron plates jib, flipped in between the 
braces aa and - the junction of the ends of the bars : and 
thefe plates bb, being prefifid by the ficrews paffing 
through the 'fides of the braces aa, xeep the ends of tiw 
bars in as dole contad.as their figures will permit; and, 
that the bars may be kept end to end in contact, the iron 
pi a te at the Nortli-end in fig. 1. and at the South-end fit. 
1 4 I 2 % 
