Reference numberMS/119/2/99
TitleLetter from John Henry Lefroy, Toronto to Humphrey Lloyd
Date15 February 1841
DescriptionLefroy discusses his arrival in Canada in October [1840], he notes there have been no disturbances for the past six months at the Toronoto Magnetic and Meteorological Observatory, and therefore he is still ignorant of all the characteristics of this station. Discussion on Lloyd's suggestion that they should discontinue the regular turn days and rely on extra observations, and Lefroy mentions Dr [Alexander Dallas] Bache from the Philadelphia observatory did not agree with this. Discussion on lack of funds for the Philadelphia observatory which is in Lefroy's opinion the best in the United States. Discussion on the observatory in Washington. Lefroy compares the observatory at Philadelphia with Toronto. Lefroy sends results of experiments on Lloyd's [tatical] needle in comparison with Mr [Robert Were] Fox's needles for measuring small changes of total force [not enclosed].The results show that Lloyd's needles are much more superior for this task. Discussion on new instructions by [Edward Sabine] that have been acted on. Discussion on changes to the apparatus and problems with it. Discussion on Sabine's St Helena observations that show an effect of the moon's daily passage on the mean pressure . Discussion on the magnetic survey.
Physical descriptionInk on paper
Access statusOpen
Fellows associated with this archive
NA7669Lefroy; Sir; John Henry (1817 - 1890)1817 - 1890
NA8252Lloyd; Humphrey (1800 - 1881)1800 - 1881
Add to My Items

    Collection highlights

    Browse the records of some of our collections, which cover all branches of science and date from the 12th century onwards. These include the published works of Fellows of the Royal Society, personal papers of eminent scientists, letters and manuscripts sent to the Society or presented at meetings, and administrative records documenting the Society's activities since our foundation in 1660.

    The Royal Society

    The Royal Society is a Fellowship of many of
    the world's most eminent scientists and is the
    oldest scientific academy in continuous existence.
    Registered charity number 207043

    Website design ©CalmView


    + 44 207 451 2500
    (Lines open Mon-Fri, 9:00-17:00. Excludes bank holidays)

    6-9 Carlton House Terrace, London SW1Y 5AG

    Email Us →


    Subscribe to our newsletters to be updated with the
    latest news on innovation, events, articles and reports.

    Subscribe →

    © CalmView