Letter 0099a (Volume 1)

Letter 99a

Faraday to Thomas, Baron Dundas[1]

23 April 1819

From a photocopy in RI MS

Royal Institution | April 23th[2] 1819

My Lord

            I have examined the salts sent me from Your Lordship and find them nearly pure Muriate of Potash. When cleaned by solution and filtration the whiter salt contains only a little sulphate of potash and a small quantity of sulphate of lime[.]

            The browner specimen contained more sulphate of potash than the first and also as before a very minute trace of sulphate of Lime. No salt of Soda exists in either of them[3].

            I have the Honor to be | My Lord | Your Lordships Most Obedient | Humble Servant | M. Faraday

Rt. Honble Lord Dundas | &c &c &c

Endorsed: 1819 | W Faraday | Rl Institution | 23d April

1. Thomas, Baron Dundas (1741-1820, ODNB). Whig politician who was a very early Proprietor of the Royal Institition.

2. Faraday originally wrote 24th but then overwrote the 4 with a 3.

3. Faraday noted this analysis in the Royal Institution’s laboratory notebook, RI MS HD/7/A, p.78, entry for 23 April 1819.