Reference numberMS/119/2/1
TitleLetter from Humphrey Lloyd, Trinity College, Dublin to Charles James Buchanan Riddell, Woolwhich
Date8 August 1839
DescriptionLloyd informs Riddell that he is in error regarding the transits. The wires in the transit telescope must not be altered as this alters the line of collimation, and there must be some way to prevent the motion when not required. The motion is only required in the telescope of the declination instrument, in the observation of vibrations. Lloyd agrees with Mr [Walter] Simms suggestion of having an additional lens at the object end and urges Riddell to adopt this.

Lloyd wrote to Mr Eardley-Wilmot regarding the vertical movement of the reading telescope and plane of collimation. Lloyd considers the usefulness of having a small riding level to the level the axis on the telescope, and includes a small diagram showing the front and end view. Discussion on the use of glass quicksilver and concave mirrors.

Discussion on currents of heated air. The importance of equal temperature.
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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