How to make a
STRIKING SUNDIAL, by which not only a Man's own Family, but all his
Neighbors for ten Miles round, may know what o'Clock it is, when the
Sun shines, without seeing the Dial.
Choose an open
Place in your Yard or Garden, on which the Sun may shine all Day
without any Impediment from Trees or Buildings. On the Ground mark out
your Hour Lines, as for a horizontal Dial, according to Art, taking
Room enough for the Guns. On the Line for One o'Clock, place one Gun;
on the Two o'Clock Line two Guns, and so of the rest. The Guns must
all be charged with Powder, but Ball is unnecessary. Your Gnomon or
Style must have twelve burning Glasses annex'd to it, and be so placed
as that the Sun shining through the Glasses, one after the other,
shall cause the Focus or burning Spot to fall on the Hour Line of One,
for Example, at one a Clock, and there kindle a Train of Gunpowder
that shall fire one Gun. At Two o'Clock, a Focus shall fall on the
Hour Line of Two, and kindle another Train that shall discharge two
Guns successively; and so of the rest.
Note, There must
be 78 Guns in all. Thirty-two Pounders will be best for this Use; but
18 Pounders may do, and will cost less, as well as use less Powder,
for nine Pounds of Powder will do for one Charge of each eighteen
Pounder, whereas the Thirty-two Pounders would require for each Gun 16
Note also, That
the chief Expense will be the Powder, for the Cannon once bought,
will, with Care, last 100 Years.
That there will be a great Saving of Powder in cloudy Days.
Methinks I hear thee say, That it is indeed a good Thing to know how
the Time passes.
Richard's Almanac, 1757