PROFESSOR AT KONIGSBERG in 



bits of wood and iron seem to serve him for the greatest 

 discoveries. 



'From there I went to the National Gallery. There are 

 some beautiful Rembrandts, and fair examples of Rubens 

 and the Italian masters, and two marvellous Murillos. In 

 the afternoon I went by omnibus to Hammersmith, a suburb 

 with villas on the Thames, to see Professor Wheatstone, the 

 physicist, and inventor of the first practicable electrical tele- 

 graph. He had left, but they gave me hopes of finding him 

 in Hull. In the evening dined at seven with Dr. Bence Jones : 

 only he, du Bois and his wife, and I. Bence Jones is a 

 charming man. Simple, harmless, cordial as a child, and 

 extraordinarily kind to me. He appointed a second meeting 

 for the next day, to see the ophthalmoscope, and took me to 

 a mechanician where Faraday's instruments for the detection of 

 table-turning are on view. On Thursday morning I worked at 

 the lecture I am to give (" On the Mixture of Homogeneous 

 Colours "). At noon, when I was going out for lunch, I met 

 Professor Pliicker from Bonn in the street, who joined me, 

 and said that Professor Sommer from Konigsberg was staying 

 in the same house with him. Afterwards I went to Bence 

 Jones, to keep my appointment. 



'On Friday Airy invited me to go to Greenwich and dine 

 with him. He had been rather stiff the first time, and can 

 be very disagreeable, but on this occasion he was charming, 

 and as I inspected all his appliances, praising much, and 

 criticizing some things, he was quite unable to stop perambu- 

 lating, so that I have probably seen more of the Observatory 

 than any one else. Besides the regular observatory, of which 

 I understood little, there are remarkably fine contrivances for 

 magnetic and meteorological observations, in which the state 

 of the instruments perpetually daguerreotypes itself, so that 

 the series of observations is more exactly and completely 

 recorded than it could be by the most accurate observer. 

 Then we saw apparatus for the electro-magnetic measurement 

 of time in star-transits, and electric clocks, which indicate 

 the time simultaneously in London and at the mouth of the 

 Thames, and at all the London railway stations. Airy's house 

 and family life were arranged, as we should say, in style, but 

 it is so with most of the English professors. His wife was 





