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NATURE 



[Oct. 1 8, 1S77 



education at Harrow. Thence he went to Trinity College, 

 Cambridge, where he gained the Person Prize in 1820, 

 was Chancellor's Gold Medallist, and graduated in 1821 

 as Twelfth Wrangler. Just after the passing of the lirst 

 Reform Bill he sat for two years in Parliament as member 

 for Chippenham, when he retired from public life, and 

 devoted himself almost entirely to work in various depart- 

 ments of science and literature. In the Royal Society's 

 Catalogue alone is a list of about fifty papers by him in 

 various domains of science, and ranging from the year 

 1822 the year after his graduation, down to 1872. The 

 first paper on the list is a mathematical one contributed 

 to Gergonne's Ann. Math. (1822), " On the Pro- 

 perties ol a certain Curve drawn from the Equilateral 

 Hyperbola." In 1S22-23 he contributed six mathema- 

 tical papers to the same journal, one ol them being " On 

 a Curve the Arcs of which represent Legendre's Elliptic 

 Functions of the first kind." He was the author of at 

 least eight other mathematical papers contributed to the 

 Royal Society, the PSiil. Trans., and the Transactions of 

 the Royal Society of Edinburgh. Some of these papers 

 are verv remarkable, as those on Definite Integrals, and 

 show Fox Talbot to have been a mathematician of no 

 small power. 



He seems to have commenced his researches on 

 light at an early period. There is, for example, in the 

 Edinburgh yoitrnal of Science, for 1826, a paper de- 

 scribing " Some Experiments on Coloured Flames ; " 

 and in the Quarterly Joiirnal of Science, for 1827, 

 one '' On Monochromatic Light." Other papers in the 

 same direction appear in the Phi/. IlJa^-., for 1833, "On 

 a Method of Obtaining Homogeneous Light of Great In- 

 tensity," " Experiments on Light," 1834, " On the Nature 

 of Light," 1835 In 1861 he published in the Chemical 

 News papers on " Early Researches on the Spectra of 

 Artificial Light from Different Sources," and " Some 

 Experiments on Coloured Flames ;" and so late as 1872, 

 we find in the Proceedings of the Royal Society of Edin- 

 burgh, " Notes on Some Anomalous Spectra," " On the 

 Early History of Spectrum Analysis," and " On a New 

 Mode of Observing Certain Spectra." 



In chemistry, as might be expected, his researches 

 were many, being mainly connected, however, with 

 photography. One of his earliest chemical papers will be 

 found in the Phil. Mag. ii. 1833 : " Remarks on Chemical 

 Changes of Colour." We find other papers contributed 

 mainly to the Phil. Mag. on Nitre, Iodide of Silver, 

 Iodide of Mercury, &c. 



In January, 1839, Daguerre published his account of his 

 process. On the 31st of the same month Fox Talbot gave 

 an account of his own process to the Royal Society, in a 

 paper entitled " Some Account of the Art of Photogenic 

 Drawing, or the process by which Natural Objects may 

 be made to delineate themselves without the aid of the 

 artist's pencil " {Roy. Soc. Proc. i S39 ; Phil. Mag. xiv. 

 1839) ; and at the meeting of the British Association that 

 year he read a paper on the subject. From that time onwards 

 he continued to write papers in connection with his in\en- 

 tion, though for several years before his death he seems to 

 have lost his interest in the subject, and turned his versatile 

 intellect to other lines of inquiry. 



The original photogenic drawing is nothing more nor less 

 than the silver printing process of the present day, which 

 has received little or no modifications since it passed out of 

 his hands, unless it be the application of albumen to the 

 paper and the fixing with sodium hyposulphite. Early in 

 1840 a new process due to Talbot created a sensation in 

 scientific circles, the results being a marked advance on 

 everything that up to that time had been produced. This 

 was no other than the Calotype or " beautiful picture " 

 process, a patent for which he took out dated 1841. The 

 main features of this process may be described as the 

 production of a photographic picture on sensitised silver- 

 odide, held /// situ in the pores of paper, and its develop- 



ment by means of gallic acid. The credit of the discovery 

 of this method of development has often been ascribed to 

 Fox Talbot ; but we believe that to the Rev. B. J. Reade it 

 is really due, but was so modified by Fox Talbot as to 

 render it manageable in the hands of the operator. The 

 next patent that Fox Talbot took out wa; registered 

 under the title of " Improvements in Calotype," in which, 

 amongst other things, he included fixing the photographic 

 image on the paper by means of sodium hyposulphite, a 

 solvent for the haloid salts of silver which Sir John 

 Herschel had used in February, 1840. 



The third patent taken out by Talbot, in conjunction 

 with Malone, was for the use of unglazed porcelain in lieu 

 of glass, on which to support the photographic image, 

 using an albumen process. In this patent also we have 

 a protection granted for an invention which has several 

 times since been rediscovered, viz., the use of a transparent 

 and flexible support in lieu of glass capable of being 

 adapted to a curved surface, by which means a panoramic 

 view might be taken in the cameia by the gradual rotation 

 of the lens round its optical centre. This flexible support 

 was paper rendered transparent and non-absorbent of the 

 liquid albumen applied to its surface. The last novelty 

 included consisted of an application of photography to the 

 production of an image on steel plates, doubtless with a 

 view of helping the engraver. 



The fourth patent was for a process (described in the 

 A/hencsum, December 6, 1851) by which instantaneous 

 pictures could be taken, and was so sensitive that an 

 experiinent undertaken at the Royal Institution to prove 

 its value is worthy of redescription. Printed matter was 

 fixed on a wheel which was caused to revolve at a rapid 

 rate, and being illuminated by the spark from a battery 

 of Leyden jars, a facsimile of it was produced in the 

 camera, " every letter being perfectly distinct." We doubt 

 if at the present day any greater degree of instantaneity 

 could be secured even by the most rapid collodion pro- 

 cesses extant. The success of the process was due to the 

 extreme sensitiveness of silver iodide when prepared by 

 double decomposition of the iron salt, and also to the 

 great facility with which silver nitrate could be reduced 

 by ferrous sulphate. The debt he owed to Dr. Woods, of 

 Parsonstown, and to Robert Hunt, who respectively dis- 

 covered these facts, Talbot duly acknowledged in his com- 

 munication to the AtheuceiDn. 



The last patented invention in photography with which 

 Fox Talbot's name is connected was that of photographic 

 engraving. This process is based on the discovery by 

 Poitivin, of the possibility, by exposure to light, of forming 

 an image in gelatine when impregnated with bichromate of 

 potassium. The steel-plate on which the etching was to 

 be engraved was covered with a dried layer of thin 

 chromated gelatine, and after exposure in the camera the 

 plate was placed in cold water to remove part of the gelatine 

 and as much of the bichromate as possible. It was then 

 covered with the etching fluid which penetrated in a 

 greater or less degree through the gelatine film and the 

 "biting-in" thus effected enabled the plate when inked up 

 and printed in the usual manner to give an impression on 

 paper of the object photographed. This method was 

 most successful in the reproduction of line engravings, 

 and when half tones had to be produced he adopted other 

 artifices to which we need not here refer. 



It has been stated that Fox Talbot did not protect his 

 processe-, but the above list of patents at once contra- 

 dicts the assertion. Not only did he — as we think quite 

 justifiably — do so, but he strictly claimed his rights, even 

 going so far as to bring an unsuccessful action for 

 infringement, claiming to include in his Calotype patent — 

 which was essentially a paper process — the collodion pro- 

 cess of Le Gray and Archer. Mr. P. Le Neve Foster 

 writes to us that Fox Talbot was so tenacious of his 

 rights that the formation of the Photographic Society was 

 for a time prevented. " I had," Mr. Foster writes, " more 



