CHANGE OF RESIDENCE. 119 



two iron bars prepared by Colby had maintained their difference. 1844. 

 There were, indeed, some good measurements of expansion, but 

 these were by Simms and his nephew, and I intend repeating 

 them with, if possible, greater rdcety. If this subject is men- 

 tioned (and it should be), say that he was unhappily arrested in 

 the act of definitely fixing the national measures. 



In the execution of his work, which was carried on in ^ ard 

 a cellar under the chambers of the Astronomical Society shanks's 

 in Somerset House, Mr. Sheepshanks recorded 89,500 observa- 

 micrometer observations. Only those who understand the tlons< 

 nature and object of these can estimate the enormous 

 labour involved. He had to make frequent visits to 

 London for this purpose. We saw him often at the time, 

 but I have only my own memory for the statement that 

 much discussion on the experiments and observations 

 passed between him and my husband, and that when 

 difficulties occurred, Mr. De Morgan was often able to 

 assist in their solution. 



We moved in July from Gower Street to Caniden Camden 

 Street, Camden Town. My husband walked to the College 

 in time to be there every morning at 8.30, that he might 

 look over the pupils' papers before giving his lecture. He 

 could not come home, as before, in the middle of the day, 

 and on this account I was sorry for the change; but 

 in other respects it was far better, as the house was 

 roomy and convenient for a young family, and the air I 

 thought fresher than in Gower Street. 



His readiness to serve his pupils and the College 

 had brought him some extra work, and some pleasure 

 in consequence. The Professor on whom the teaching of 

 Mathematical Physics devolved proved quite unequal to 

 his task. The pupils who came to him from the Mathe- 

 matical class were already much his superiors in know- 

 ledge, and in their strait they appealed to my husband. 

 With the approbation of the Council, he at once undertook 

 to meet the difficulty. He gave, during the remainder of 

 the session, e^tra time and instruction to these young 



