Nique-Taghil le 16er de Mai 1781

I dispatched 2 or 3 scraps of letters to you from hence a few days

ago; but I shall not let pass an opportunity which just offers of giving

you another scrap.

The commissions which I gave you for wearables I drop

entirely; but I must give you another of a different kind. I do not

sufficiently understand the mechanism of wind mills or rather I am not

acquainted with the dimensions to which they may be extended.

The principles on which they act can need no illustration to any one who

has sailed in a boat.

What I want then is the dimensions of the Vanes as well as of the axis &c

the means of presenting them so as to suit all

directions of the wind, and of increasing & diminishing the quantity of

sail. All this I can easily enough invent, but I wish to know how it is

actually practised in the most approved mills, and at the

same time whether any new mode of applying the force of wind to produce a

circular motion has made its appearance lately. Remember that those parts of

a Windmill which are to adapt it to the grinding of corn I am not in want

of.

Now how are you to get this information. I don't know of your having any

mechanical friends who could give it you directly.

You might go to Nairne and inventing some story or other to account for your

curiosity. Desire him to inform himself if he does not know of the length

of the Vanes of a windmill. This is the principal Quere.

There are 2 or 3 remarkably large windmills on the River Thames

below Wapping at Limehouse or the Isle of Dogs, which I have been used

to see in passing. They had a contrivance which I much admired of

staying or supporting the extremities of the Vanes by a rope

to each which are fastened at their other ends all to the axis produced.

the axis produced.

I give you leave & desire you to employ two afternoons

to procure me this information but no more. Do it however immediately

and send also by the first Courier directed to Sir James Harris any good

book there may be

on the subject of both wind & water mills. The bulk

must not be greater than 2 small quartos.

There is a change in any plan since I wrote my last which though

contrary to my usual prudence I will

'een tell you of. Finding some clever workmen and being

likely to be detained a month longer by the making this new invented

travelling carriage, I have determined to try here my machine of

which I