144 Annals of the Philosophical Club 



idea of a Royal Society Relief Fund was discussed, and 

 strongly supported. 1 



To those present at the lOQth meeting (Feb. 24th) Mr. 

 Wheatstone exhibited the results of experiments made 

 by M. N. de St. Victor with nitrate of ammonia and per- 

 manganate of potash in order to produce a specially sensitive 

 paper. Copies of engravings were taken in about fifteen 

 minutes by using the former salt, while the blue impressions 

 resulting from the latter required an hour for their com- 

 pletion. Another experiment was to wash over a paper 

 with tartaric acid, expose it to sunlight for two minutes, 

 then roll it up loosely and enclose it in a dark metallic case, 

 where it was Jeft for six minutes. At the end of that time, 

 the case was opened, a few drops of water thrown in, the 

 whole warmed, and the case inverted over a sheet of photo- 

 graphic paper, above which was placed the original to be 

 copied. In a few minutes a negative transfer was effected, 

 developed, and fixed in the usual manner. Mr. Busk 

 mentioned an experiment, made about twelve years ago, in 

 which paper was washed in the dark, first with nitrate of 

 silver, next with tartaric acid, and then placed between the 

 closed leaves of an old printed book for twelve hours. After 

 being removed in the dark, it gave, on exposure to sunlight, 

 a copy of the printed page. A copper-plate engraving, 

 however, did not admit of this kind of transfer. 



At the noth meeting (March 24th) Dr. Bence Jones read 

 a letter from Professor Du Bois-Reymond. His experiments 

 had shown that, if the sciatic nerve were divided on one 

 side of a rabbit, and the animal then killed by strychnine, 

 the muscle in the paralysed limb had an alkaline reaction, 

 and that in the tetanized part an acid one. The result was 

 unfailing in rabbits, but not always so in dogs. One of his 

 pupils had proved the indirect irritability of muscular fibre 

 by showing that, after the destruction of the nerve, hydro- 



1 The idea was further discussed at the next meeting, and the Treasurer 

 requested to write to each member of the Club to ascertain his opinion 

 on the subject (the Minutes contain a copy of the letter). The fund was 

 established in the course of the year ; see page 52. 



