[ 754 ] ' 
uniformly extended or contra&ed, each Angle mud 
contain the fame Number of Degrees and Minutes 
as before. Hence this Objection falls no harder on 
the Table, than on all other Inftruments. 
And here I intended to have ended this Difcourfe : 
But as I have fome other fmall Improvements, not 
only in the Inftrumental Part, but in a new Method 
of difpofing the Maps, and better adapting them to all 
fubfervient Ufes ; I proceed. 
I fhould have faid before, that each Chart has a 
Flower de Lys on its North Edge ; and, as the Needle 
is moveable to any Side, Care muft be taken, that 
the North End of the Needle, when it ftands, fhould 
point the fame Way as the Flower de Lys on the 
Charts. , 
I ufe a Needle about Five Inches long, placed in 
an oblong wooden Box, but juft fo wide as the Needle 
may play double the Degrees of the Variation Weft, 
‘viz. 30°. In the Middle of one End is the Flower 
de Lys , and the Box is by Studs and Holes always 
put on the Table oblique to the Quantity of the Mag- 
netical Variation. I make no other Ufe of the 
Needle, than to fet the Table in the Meridian, and to 
prevent any great Miftakes, in joining or placing the 
Charts wrong. 
I have no more than half an Inch of the Needle 
that appears from under the Table, for the Reafon it 
fhould not be in the Way, or fo fubjefl to be damaged : 
The making the Box fo narrow, is to check its play- 
ing, that it may fooncr hang ftill over the Flower de 
Lys. The wooden Box, lined with Paper, I find pre- 
ferable to a large brafs Box, and large Glafs,. which 
in 
