Explains discrepancies in weights and measures caused by changes since 1836 in apothecaries' measures.
EC has found that a discrepancy in A. W. von Hofmann's experiments with iodine solutions resulted from an error in Hofmann's use of decimals.
Reports S. P. Woodward's opinion of the Origin: "a very sad book, it unsettles all one's religious principles and the worst of it is so much of it is true".
1 Greek St—
10 Nov '60—
My dear Sir,
The discrepancy in regard to the weights & measures I think admits of explanation— Previously to 1836 the old Wine measure was in use and served as the basis of the fluid apothecaries measure in this wise— The gallon or congius was the unit this was divided into 8 parts octarii or pints— each of which was considered roughly to weigh a pound— in point of fact it weighed 7289.7 grains a pound avoirdupois is 7000 grains— well then this old wine pint thus roughly assimilated to a pound was divided into 16 fluid ounces—&c thus—
Subsequently to 1836 the new measure came into operation by which the pint in lieu of containing 28.875 cubic inches was made to hold 34.659 cubic inches to meet this change the apothecaries subdivided the new pint into 20 fluid ounces instead of 16— still retaining the old subdivision into drams scruples & minims but their weights became materially altered— the old fluid ounce contained 455.6 grains of distilled water the new contains 437.5— the old fluid drachm contained 56.9 grains, the new 54.7 grains— I dont know whether you have the subjoined table but it is a very useful one—
It is convenient if you have not a measuring glass to weigh out your measure with a
pair of scales in fact it is more accurate for the glasses are often very
indifferently graduated only of course you must not consider a very heavy or very light
liquid weighs the same per gallon or per pint as water— a gallon
of ether weighs 7
I have called on Hofman and had from the explanation he gave
me written to you that his note was quite correct but having penned the passage I
checked the figures from the data he gave me and found they did not work out rightly so
I cancelled a page and called again this morning at the College of Chemistry and saw his
Secretary, as it was merely a matter of figures I would not
trouble the D
So that in the D
While writing Woodward Brit Mus—came in and I always like to stir him up about the Origin, ``Ah he says it is a very sad book, it unsettles all one's religious principles and the worst of it is so much of it is true— It is just like all those Geologists they say they dont know whether God made the world or the Devil and it is my opinion they dont care!'' He says Owen is a worse materialist than you are— What a dreadful man he must be!—
I delayed answering till I could see Hofman— pray write if I can do anything more for you—
Yours most truly | E Cresy.
I sincerely trust from your not mentioning your daughter that she is rapidly
amending— Pray present our best respects to M
C Darwin Esq—
- f1 2980.f1See the two letters to Edward Cresy, 2 November .
- f2 2980.f2August Wilhelm von Hofmann had sent Cresy information for CD on the sensitivity of chemical tests. See letters from A. W. von Hofmann to Edward Cresy, 13 October 1860 and 27 October 1860.
- f3 2980.f3Cresy may be referring to Herbert McLeod, who was assistant chemist to Hofmann at the Royal College of Chemistry (see James ed. 1987).
- f4 2980.f4Cresy forwarded the letter from A. W. von Hofmann to Edward Cresy, 27 October 1860, enclosed in the letter from Edward Cresy, 30 October 1860.
- f5 2980.f5Taylor 1860, p. 12. See the enclosure with the letter from Edward Cresy, 30 October 1860.
- f6 2980.f6See second CD note.
- f7 2980.f7Samuel Pickworth Woodward was first-class assistant in the department of geology and mineralogy of the British Museum. He was known to be strongly against the views CD put forward in Origin (see Correspondence vol. 7, letters from J. D. Hooker, [21 November 1859]).
- f8 2980.f8Richard Owen was superintendent of the natural history departments of the British Museum.
- f9 2980.f9The note is associated with the letter in DAR 58.1: 8. CD crossed in pencil the first page of the note, from `Look' to `segregation'.
- f10 2980.f10The note is in DAR 143 with the copies of correspondence between CD and Cresy. Although there is no indication when CD wrote the note, it seems to be related to the information Cresy gives in this letter.