[ 755 ] 
in cold and hazy Weather, condenfes the Vapour and 
Air fo much, as to make the Needle very languid 
and dull. 
Farther Ufes , by taking a Survey in the new Method 
by the Plotting-Table. 
The Charts, thus taken, are more readily laid to- 
gether by Numbers on their Edges, which tally, and 
make up the whole Map in one Plan, or View, and 
are, in thefe Squares, more portable. 
In the fecond Place, they are more readily copied, 
extended, or contracted. For, by having a Frame of 
Wood that juft encompafles a Chart, divided by 19 
Threads at equal Diftances, and the fame at Right 
Angles, the other Way; each Five or Ten, &c. be- 
ing diftinguifhed by Silk of a different Colour ; a 
Reet is made of 400 Geometrical Squares, from 
which, having a Velumn or Paper fo divided by lefter 
or greater Squares ; then drawing or copying by Help 
of the Lines into thofe new Squares, you have your 
true Map contracted or extended. 
Large Maps of Lordfhips are not any ways con- 
venient, or portable, to have recourfe to on the Spot 
or Place they reprefent; being fubjeCl to Damages, 
unfit to be opened in rainy Weather, very trouble- 
fome in the Wind, and very difficult to find out the 
Part you want. To remedy all thefe Inconveni- 
ences, fome Years ago I contrived a new Method of 
difpofmg them, in fuch Manner as makes them more 
fure, fafe, ready, convenient, durable, and portable, 
than any other Method. 
5 F 
And 
