for carrying Vessels out of and into Harbours , fyc. 277 
raised at the same time as the wheel II h performs its office, so 
that it is in effect two machines, acting alternately by the weight 
of one pillar of air of such a diameter as the diameter of the cy- 
linder is. 
44 If it should be said that this is not a new invention, because 
I make use of the same power to drive my machine that others 
have made use of to drive theirs for other purposes, I answer, 
The application of this power is no more than the application of 
any common or known instrument used in mechanism, for new 
invented purposes. 
44 Answers to some Queries that have been made , concerning the 
Possibility and Us fulness of this Undertaking. 
44 Query 1 .—Is it possible to fix Instruments of sufficient 
Stiengthy to move so prodigious a Weight , as may be contained 
in a very large Vessel f 
44 Answer. — All mechanics will allow it is possible to make a 
machine to move an immense weight, if there is force enough to 
drive the same ; for every member must be made in a propor- 
tionable strength to the intended work, and properly braced 
with laces of iron, &c. so that no part can give way or break. 
If the braces, &c, necessary for this work, had been put in the 
draught, it would have been so much crowded with lines, that 
the main instruments could not be so well perceived. 
44 Query II. — Will not the force of the waves break any instru- 
ment to pieces , that is placed to move in the water ? 
44 Answer. — 1st, It cannot be supposed that this machine will 
be used in a storm or tempest at sea, when the waves are very 
raging ; for if a merchant lieth in harbour, &c. he would not 
choose to put out to sea in a storm if it were possible to get out, 
but rather stay until it abated. 
44 2c%, When the wind comes a-head of the tow-boat, the fans 
will be protected by it from the violence of the waves ; and 
when the wind comes sideways, the waves will come edgeways 
of the fans, and therefore strike them with the less force. 
44 3 dly. There may be pieces of timber laid to swim on the sur- 
face of the water on each side of the fans, and so contrived as 
they shall not touch them, which will protect them from the 
force of the waves. 
