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Document number: 2629
Date: 08 Mar 1833
Recipient: TALBOT William Henry Fox
Author: BREWSTER David
Collection: British Library, London, Manuscripts - Fox Talbot Collection
Collection number historic: LA33-9
Last updated: 2nd February 2018

My Dear Sir,

I received your letter when I was in the middle of a Paragraph of my Paper on the Spectrum <1> mentioning your suggestion that the error in Fraunhofer’s <2> Map might be only apparent, and owing to changes in the Suns light itself. I was thus induced to watch narrowly for any appearances that might initiate great changes; I at last discovered them; but a careful examination proved that those changes depended on the proximity of the Sun to the horizon, and that they were lines and bands produced by the Atmosphere of the Earth. I put great value on this discovery. We may soon be able to observe the action of the Atmospheres of all the Planets <3> upon the Solar light which they reflect, and thus derive some knowledge of their actual composition.

Ever since I had the pleasure of seeing you I have devoted my whole time to the examination of the Spectrum. By new methods of observation, which I believe have never before been used in optical researches, I have discovered hundreds of lines which Fraunhofer never saw, & have nearly completed three Maps of the Spectrum, one on a scale of about 4 feet 8 inches, containing only the Solar lines, & so full, that I have been obliged to execute parts of it on a scale of 17 feet, a record on the same scale shewing the lines produced by Nitrous Acid Gas in Artificial White light; and a third showing the Gaseous & the Solar lines combined, & produced by transmitting the Suns light thro’ the Nitrous Acid Gas. This last Map affords ocular demonstration of the general identity of the two classes of lines. Profr Airy <4> to whom I shewed the experiment here last Autumn described the phenomenon by saying that he saw the one set of lines thro’ the other.

As it is impossible to complete in a proper manner these researches, in a climate like this, & with the ordinary Instruments that an Individual can obtain, I have applied to the Royal Society <5> to enquire if they would devote any of their funds for the purpose of obtaining splendid instruments or for completing these observations in Italy. I am willing to sacrifice all the my time for the task, but I can do more, <6> having already during the whole of my life sacrificed half my time and devoted half my professional income to Science. Mr Lubbock <7> writes me, with regret, that the Society have just devoted all their Donation fund to Capt Ross’s <8> Expedition, but suggests that the Duke of Sussex <9> will apply to Government if I make a distinct application to his R.H. <10> Altho’ I am an ardent political friend to the present Government, I believe they have not the heart to do any thing for Science.–

I am unacquainted with the provisions of Mr Godson’s <11> Bill for a New Patent Law. I have devoted much labour to that subject; but I believe there is neither knowledge nor liberality in Parliament, to pass any Bill of real use to Inventors. Until England has a stable Government, and ceases to be under the influence of inveterate factions, she will never do any thing essential to promote Science, Literature or the arts.

The Paragraph from the newspapers is quite authentic. I sent a notice of the fact to a friend in Edinr; but the phenomena of the new salt are far more interesting than they are there described. It exercises a most unique definite action on the Red Rays on the least refrangible side of B, and absorbs bands near C. It is red in Candle light & Blue in day light, & its solution at different thickness is Green Blue, & Red. The oxyhydrogen Microscope seems to be scarcely a Novelty. It is only the Lucernal Microscope, <12> with a stronger light.

There are now more Scientific men in the House of Commons than there ever were before. I hope you will exert yourself on the subject of the Patent law, and in that of Lighthouses <13> both of which will occupy your attention this session. I hope however you will not forget your Scientific pursuits. Your power of doing something original and valuable and your leisure and means of doing it should not be neglected for the infinitely less valuable occupations of a political life. It will give me great pleasure to hear from you when you have an idle moment,

and I am My Dear Sir Ever Most Truly yrs
D Brewster

Allerly by Melrose
March 8th 1833

H.F. Talbot Esq M.P.
31 Sackville Street


1. David Brewster, ‘Observations on the lines of the Solar Spectrum, and on those produced by the Earth’s Atmosphere, and by the Action of Nitrous Acid Gas’, Transactions of the Royal Society of Edinburgh, v.12, 1834, pp. 519–530. Read at the meeting of the RSE, 15 April 1833.

2. Joseph von Fraunhofer (1787–1826), optician, Munich. See Doc. No: 02423 for Brewster’s concern about the accuracy of his spectrum map.

3. Brewster here anticipates Anders Jonas Angström (1814–1874), founder of astronomical spectroscopy.

4. Sir George Biddell Airy (1801–1892), Astronomer Royal.

5. Royal Society of London.

6. He probably means ‘I can do no more’.

7. Sir John William Lubbock, 3rd Baronet (1803–1865), mathematician & astronomer.

8. Sir James Clark Ross (1800–1862), explorer of the Arctic and Antarctic. He seems not to have mounted an expedition until 1836.

9. Augustus Frederick, Duke of Sussex (1773–1843), president of the Royal Society (1830–1838).

10. His Royal Highness.

11. Richard Godson (1797–1849), MP for Kidderminster (1832–1835). On 19 February 1833 he had sought leave to bring in a Bill ‘to amend the laws respecting Letters-patent for inventions’

12. A microscope in which the stage is illuminated by a lamp.

13. Brewster had devised a lens-based lighting system for lighthouses and fought without success to get his system recognised.

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