Reference numberMS/119/2/68
TitleLetter from Humphrey Lloyd, Kilmarnock Cabinteely to Charles James Buchanan Riddell
Date24 November 1845
DescriptionLloyd has been occupied with the business of University [of Dublin] examinations over which Lloyd’s office is presiding over, therefore he has been unable to reply to Riddell’s letter. In Lloyd’s opinion there is no possible objection to placing the two soft iron bars so that their permanent magnetism may oppose one another. Riddell is also correct in determining the temperature correction of the iron bars.

Lloyd would like to see Riddell’s comparison of the variation of dip as deduced from the horizontal force, vertical force, and induction inclinometer. Riddell mentions that they agree in law but differ in amount. Lloyd feels that they do not have the right method of determining the coefficient and hopes to test this question before any results are published.

Lloyd informs Riddell that he does not have a copy of [Edward] Sabine’s pamphlet regarding the description of the the theodolite magnetometer] but will send one if he is able to.

Discussion on the theory that hollow cylinders are as powerful as solid ones of the same diameter, taken up by [Peter] Barlow’s research, and Lloyd’s suggestions for additional tests.
Physical descriptionInk on paper
Access statusOpen
Fellows associated with this archive
NA8252Lloyd; Humphrey (1800 - 1881)1800 - 1881
NA7327Riddell; Charles James Buchanan (1817 - 1903)1817 - 1903
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