From Edward Frankland 16 October 1873
14 Lancaster Gate | Hyde Park W.
Oct. 16/73
My dear Sir,
The litmus paper possesses what chemists call a neutral tint.1 It is very sensitive to acids & still more so to alkalies. The longer piece which I return has been half immersed in a mixture of 1 part of sulphuric acid and 100,000 parts of water. I know not in what condition it may reach you but, as I write, the difference of tint (bright red & port wine red) is so strong, that, it can scarcely be doubted, a very much smaller proportion of acid could be detected.
You will find that the paper will most distinctly indicate the alkalinity of any chalk-spring or well water that you may have in your neighbourhood.
If you would like some bluer but less delicate, I shall have great pleasure in sending you some & would do so now but do not happen to have any at hand as I write.
Believe me | Yours sincerely | E. Frankland.
Footnotes
Summary
Sends some litmus paper for CD.
Letter details
- Letter no.
- DCP-LETT-9098
- From
- Edward Frankland
- To
- Charles Robert Darwin
- Sent from
- London, Lancaster Gate, 14
- Source of text
- DAR 164: 209
- Physical description
- ALS 3pp
Please cite as
Darwin Correspondence Project, “Letter no. 9098,” accessed on 19 October 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-9098.xml
Also published in The Correspondence of Charles Darwin, vol. 21