1794

Thomas Beddoes to James Watt, 4 September 1794

Sep^r 4^th 1794

Dear Sir

I received your letter & its enclosures. I wrote yesterday to beg for an air-apparatus to be sent as soon as possible to Mr Knight Painswick Gloucestershire – I will abridge yours of the 17^th <of June> if you please – if not, you will just have time to rewrite it – but if you can trust my discretion in so delicate a matter, you may depend upon my exerting it to the best of my power – I wish the 2^nd part of the description may come in 2 or 3 days – the printer is now composing the description & I hope the publication will very soon be ready. I shall hasten it as much as I can –

If you will send me a small apparatus with condenser & hydraulic bellows of tinned copper, I sh^d be much obliged to you. There can be no doubt but I shall be able to part with it in the course of the winter; [when] some opulent patient in the country will want it & I shall have it ready at short warning – I do not think I c^d get the apparatus manufactured here – where I find the workmen not at all handy. I hardly think the concentration of the vitriolic acid from its forming insoluble crusts of gypsum can account for the superior purity of air from the Ex^r Manganese, because the manganese, being in powder, presented a large surface & the heat was great – If as you advise or rather think adviseable the dephlog^d air is best procurable from vit^c acid & manganese (which is decidedly my opinion) The apparatus sh^d include a sand-pot adapted to the furnace & equal to a 2 quart retort – Then I think nothing essential will be wanting – & if you will be so good as to order such a sand-pot to the above small apparatus, I sh^d be obliged to you – I think a short chimney sh^d be contrived – & if a cover with such a chimney & a hole for the pot can be cast in one piece, this w^d be simpler than any thing I can think of at present –

As soon as I get some Ex^r Manganese, I shall try it along with the Mendip. I suppose you will apply water to Mang. as you have to nitre – Will not this save the pot? – Is the difference of temperature at which nitre gives out air abundantly with water & slowly without water considerable? Will either nitre or manganese give it at a heat below red <when water is used>? Mr Berthollet says the azote comes at an opake heat & the oxygene, requiring light, at a red heat, but although this is pretty it is not true – of either air –

Yours sincerely

Thomas Beddoes

Address: James Watt Esq / Heathfield / Birmingham
Endorsement: Dr Beddoes / Sept 4^th / 1794
MS: LoB MS 3219/4/28/14