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Darwin Correspondence Project

From W. K. Bridgman   23 January 1869


Jan 23/69

Dear Sir

I hope you will allow me to thank you which I do very much indeed for your kind & very interesting letter—1 The observation respecting the apparent simultaneous appearance of nectar with the bursting of the anthers was only casually made with a common hand lens when cutting off the flowers to obtain the pollen—2

Since then, however I have arranged a Binocular with 112 object glass. 2@. —eye pieces & a Beck’s side reflector in such a manner as to receive a continuous view of any individual flower from its first opening to the shedding of the pollen—3 by this means I am enabled to obtain a distinct & sufficiently enlarged view of the disc as to be able to detect the slightest exudation immediately it appears— I have several male plants in different stages of forwardness & by examining a succession of flowers & noting the times of the anthers beginning to burst, & the first appearance of the nectar together with the time of day it occurs the presence or absence of sunlight &c. &c. something perhaps may be learnt on the subject— That fertilisation is designed to be carried on here by organic agency, I think, scarcely admits of a doubt, but whether by night feeders or by day feeders I am inclined to believe is not quite so clear—

The flower is singularly favorable in structure for examination, the clumping filament with its anthers & the nectary being in the [field] at the same time   if you would like to have a few expanded & unexpanded flowers I shall have very great pleasure in sending some in all their stages

I have plenty of female plants but none yet in flower—

With respect to the Polygala, Linaria &c it will be a very interesting expt to try & discover whether the absence of nectar be synchronous with the absence of the bees or perhaps it may be more owing to the state of the weather to which we know them to be remarkably sensitive although it is just possible that there may be something which serves them as a “Beggars mark” with which we are yet unacquainted—4

Again thanking you allow me | to remain Dear Sir | Yours faithfully | W K Bridgman

C Darwin Esq FRS


See letter from W. K. Bridgman to J. G. Jeffreys, [before 21 January 1869].
Bridgman refers to a binocular microscope with a parabolic side reflector attachment, manufactured by Richard & Joseph Beck, 31 Cornhill, London (Post Office London directory 1868).
See letter to W. K. Bridgman, 21 January [1869] and n. 3. ‘Beggars mark’ may be a reference to the secret sign-language used by tramps (Rose 1988, p. 33).


Post Office London directory: Post-Office annual directory. … A list of the principal merchants, traders of eminence, &c. in the cities of London and Westminster, the borough of Southwark, and parts adjacent … general and special information relating to the Post Office. Post Office London directory. London: His Majesty’s Postmaster-General [and others]. 1802–1967.

Rose, Lionel. 1988. ‘Rogues and vagabonds’: vagrant underworld in Britain 1815–1985. London: Routledge.


Is assembling apparatus of lenses and reflector to observe flower from opening to first shedding of pollen, and to determine whether fertilisation is by night- or day-feeders.

Will also examine reasons for absence of nectar in Polygala linaria.

Letter details

Letter no.
William Kencely Bridgman
Charles Robert Darwin
Sent from
Source of text
DAR 160: 307
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 6571,” accessed on 19 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 17