Reference numberMS/119/2/54
TitleLetter from Charles James Buchanan Riddell, Woolwich to Humphrey Lloyd
Date4 April 1844
DescriptionRiddell informs Lloyd that he has followed Lloyd’s instructions closely regarding the new instrument with the exception of altering the graduations of the deflecting bar from tenths of inches to hundredths of a foot. This is easily changed if Lloyd would prefer, however Riddell suggests keeping this alteration as the decimals of a foot are more convenient with the calculator and with portable instruments.

Discussion regarding the instruction for absolute declination. Riddell expresses his confusion about how the line of collimation of the magnets is to be adjusted.

The instructions will be closed and set to print as soon Riddell hears from Lloyd.

Riddell has sent the printed specifications to Mr [Samuel] Jones and asked him to revise the list of prices, as Lloyd was not happy with the price of £35.

Discussion about additional work on the telescope.

Riddell notes the list of instruments has increased since he started compiling the instructions two years ago.

Riddell discusses the description of Lloyd’s new instrument, and thanks Lloyd.

Discussion on Lloyd’s comments regarding Riddell’s fixed observatory instructions. Riddell discusses the requirement of a separate set of instruments and alterations to the bifilar. Riddell’s instructions are to be used by officers and others engaged in surveys who know nothing about magnetism as a science or of the magnetical instruments, but if ordered to make observations could do so if provided with sufficiently detailed instructions. Riddell argues this is the reason to keep higher scientific matter out of the instructions.
Physical descriptionInk on paper
Access statusOpen
Fellows associated with this archive
NA7327Riddell; Charles James Buchanan (1817 - 1903)1817 - 1903
NA8252Lloyd; Humphrey (1800 - 1881)1800 - 1881
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