June 4, 1914] 
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his subject the atomic theory. From one to four 
o’clock various manuscripts and other objects 
of interest in connection with Roger Bacon and 
his successors will be on view in the Bodleian 
Library, and from four to half-past six a garden 
party will be held at Wadham College. 
At the ‘approaching celebration the Vatican 
library will be represented by Mgr. Ratti, the 
Institut de France by the Comte d’Haussonville, 
the University of Paris by Prof.- Picavet, the 
University of Cambridge by Prof. James Ward, 
the Order of Friars Minor by Dr.. P. Hickey, 
Provincial, and Prof. Paschal -Robinson, the 
Capuchin Order by Fr. Albert (vicar-provincial), 
and Fr. Cuthbert. Rae 
Much has been done of recent years te establish 
the importance of the work of Roger Bacon in) 
the history of Western thought. His-eminence as 
a linguist, an educational reformer,-a mathema- | 
tician, and physicist was well brought. out in:the 
discourse lately delivered by Sir. John Sandys 
before the British Academy.» The late Prof. 
Adamson, speaking of his works, both edited. and 
at present existing only in manuscript, .wrote as 
follows in the “Dictionary. of National Bio- 
graphy ” :— Es ; 
It is much to be desired that a more thorough and 
detailed study of the known manuscripts and a more 
extensive search for others which doubtless exist should 
be undertaken. Some portions are in a condition suit- 
able for publication, and it is well-nigh an obligation 
resting on English scholars to continue the good work 
begun by the late Prof. Brewer. | Bacon’s works 
possess much historical value, for his rigorous think- 
ing and pronounced scientific inclinations are not to be 
regarded as abnormal and isolated phenomena. He 
represents one current of thought and work in the 
Middle Ages which must have run strongly though 
obscurely, and without a thorough comprehension of 
his position our conceptions of an important century 
are incomplete and erroneous. 
Prof. Picavet, of the Collége de France, adds 
his testimony as follows :— 
L’autorité et le raisonnement ne valent, pour Roger 
Bacon, qu’en fonction de l’expérience. C’est elle qui 
doit prononcer en dernier ressort sur les affirmations 
des anciens comme sur nos propres conceptions. .. . 
Roger Bacon a donc entre les mains l’instrument qui 
a rendu possibles toutes les conquétes de la science 
moderne. 
Subscribers of one guinea and upwards to the 
Roger Bacon commemoration fund will be entitled 
to take part in the ceremonies at Oxford, and 
also to receive the memorial volume, which will 
contain essays dealing with various aspects of 
Roger Bacon’s work, written by specialists in the 
various subjects. Subscriptions should be sent to 
Col. W. H. L. Hime, 20 West Park Road, Kew. 
SIR. JOSEPH WILSON SWAN, F.R.S. 
WE regret to announce the death, in his eighty- 
sixth year, of Sir Joseph Swan, at War- 
lingham, Surrey, on May 27. Swan came from a 
stock exceptionally endowed with inventive abilities 
on both the paternal and maternal sides, his father 
and his maternal uncle, Robert Cameron, having 
both been inventors of note.. He was born at 
NO. 2327, VOL. 93] 
Sunderland on October 31, 1828, and there he 
received his. education... He was removed from 
school at-an early age, and having shown a de- 
cided taste for chemistry, was apprenticed by his 
father in the chemical business of Mawson, of 
Newcastle; of this firm Swan subsequently be- 
came a partner, the firm’s name being changed 
to that of Mawson and Swan. At the commence- 
ment of his career Swan turned his attention more 
particularly to the manufacture of photographic 
supplies, and it is owing to his enterprise that the 
business of his firm was largely extended in this 
direction. ; 
The nature of the business with which young 
Swan was thus associated enabled him to turn to 
account his inventive talent in bringing about im- 
portant-advances in photography. His patent for 
carbon printing, being the first commercially prac- 
ticable process of the kind, was filed in 1862; 
later he. described it in a-paper read by him before 
the Photographic Society in April, 1864. Al 
though the process has been simplified and im- 
proved. by subsequent workers, in its essential 
features Swan’s invention remains the basis of 
some of the methods of photographic reproduction 
still largely in use at the present day. An original 
investigation made by Swan on the effect of heat 
in increasing the sensitiveness of a gelatino- 
bromide silver emulsion led to the production by 
him of extremely rapid dry plates in 1877, and two 
years later he invented the bromide printing 
process. 
Swan is, perhaps, better known to the public in 
connection with his invention of the incandescent 
carbon filament lamp than in connection with his 
discoveries in the field of photography. As a 
lad he had, in 1845, seen the experiment carried 
out of heating platinum-iridium wire to incan- 
descence by means of an-electric current, and this 
principle was applied by him, so far back as 1860, 
in the construction of an electric glow lamp, in 
which strips of carbonised paper or card mounted 
within an exhausted glass globe were raised to a 
red heat by an electric current obtained from 
primary batteries. At that date the method avail- 
able for obtaining a vacuum was not entirely 
satisfactory, and in consequence the life of the 
earliest type of glow lamp was exceedingly short. 
However, when Sprengel’s mercury pump for 
producing vacua made its appearance in 186s, 
Swan again turned his attention to the problem 
of producing a marketable electric glow lamp. 
Experiments carried out by him showed that high 
vacua were necessary to prolong the life of the 
incandescing filaments of which he «had been 
investigating the properties. 
In February, 1879, Swan exhibited his im- 
proved electric glow lamp at a meeting of the 
Newcastle Chemical Society, and the first public 
demonstration on any considerable scale of this 
new method of illumination was given before the 
Newcastle Literary and Philosophical Society in 
October, 1880. In the following month Swan 
read a paper before the Institution of Electrical 
Engineers on “The Subdivision of the Electric 
