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Darwin Correspondence Project

To Edward Cresy   2 November [1860]1

15 Marine Parade, Eastbourne

Nov: 2nd.

Dear Cresy

I return by this post Dr. Taylor’s pamphlet which is very interesting.—2

This morning I vowed to myself that I would give you no more trouble; this evening I break my vow! Do read over Hofman’s note,3 it seems to me clear that he asserts that he has easily distinguished 0.002 of milligram of iodine and this equals, as I make out, 3/100,000 of a grain! Whereas Taylor, in your copy, speaks of only 11400 of a grain.4 Can you understand this? Pray do not trouble Hofman again, for I shall see him in course of early winter. Now I am on weights, can you assist me in another point. I have used ordinary apothecary measures (which I shall state in my paper), viz, fluid oz. divided into 8 drachms and each drachm into 60 minims,—so that each oz. contains 480 minims.5 But when I looked into such books as I possessed I found the most ridiculous discrepancies and misprints of weight of one such oz. of distilled water. I applied to good and clever druggist and he says positively one such oz. weighs 437.5 grains and this agreed with one of my printed authorities; so I have provisionally used it in calculating proportions. Can you anyhow aid me in telling me whether this is correct?6

God forgive me for being so troublesome, and believe me, | Yours very sincerely | C. Darwin

Please return Hofman’s note.

Footnotes

The letter was written in the evening, after the preceding letter was posted.
Taylor 1860. See preceding letter.
Taylor 1860. There is a note on this pamphlet in DAR 60.1: 69 listing the amounts of arsenic and antimony that could be detected.
A note giving these calculations and apparently subsequent emendations is in DAR 60.1: 70.

Bibliography

Taylor, Alfred Swaine. 1860. Facts and fallacies connected with the research for arsenic and antimony; with suggestions for a method of separating these poisons from organic matter. Guy’s Hospital Reports 3d ser. 6: 201–65.

Summary

Discusses pamphlet by A. S. Taylor

and note by A. W. v. Hofmann concerning iodine solution.

Letter details

Letter no.
DCP-LETT-2974
From
Charles Robert Darwin
To
Edward Cresy, Jr
Sent from
Eastbourne
Source of text
DAR 143
Physical description
C 2pp

Please cite as

Darwin Correspondence Project, “Letter no. 2974,” accessed on 23 May 2022, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-2974.xml

Also published in The Correspondence of Charles Darwin, vol. 8

letter