Letter from Erasmus Darwin to Matthew Boulton, 1763/07/01
Darwin asks Boulton to help him with some apparatus for his scientific experiments.
Jul. 1. 1763
As your are now become a sober plodding Man of Business, I scarcely dare trouble you to do me a Favour in the nicknachatory, alias philosophical way: I have got a most exquisitely fine Balance, and a very neat Glass Box, and have all this day been employ’d in twisting the Necks of Florence Flasks – in vain!
Now if you like Florence Wine, I begg to leave to make you a present of one Bottle, or two, if the first does not answer, to drink success to Philosophy and Trade, upon the condition that you will procure me one of their Necks to be twisted into a little Hook according to the copper Plate on the reverse of this Paper: It must be truly hermetrically seal’d, air-tight, otherwise it will not answer my End at all.
Harrison’s Clock at last has not a progressive Ballance, but an interrupted one, like the common Time-pieces, except in Weight and Workmanship.
I am extremely impatient for this new Play-Thing! as I intend to fortell every Shower by it, and make great medical discovery as far as relates to the specific Gravity of Air: and from the Quantity of Vapor. – Thus the Specific Gravity of the Air, should be as the Absolute Gravity (shew’d by the Barometer) and as the Heat (shew’d by Boulton’s Thermometer). Now if it is not always found as these two (that is as one and inversely as the other) then the deviations at different Times must be as the Quantity of dissolved Vapour in the Air.
The common Hygrometers only shew when the Air is in a Disposition to receive or part with moisture, not at all the Quantity it contains. – I begg my Compl. to Mrs Boulton and Mr and Mrs Fothergale, and am, dear Boulton, your affectionate Friend,