Referee's report by Charles Chree, on a paper 'Magnetic observations in Egypt, 1893-1901' by Henry George Lyons

Description

Sectional Committee: Physics and Chemistry

As a record of magnetic data in a region of which comparatively little is known the papers seems to merit publication. It does not however suggest either wide knowledge of terrestrial magnetism or the possession of any special critical faculty, thus the value of some of the data is open to considerable doubt. The facts should be presented more critically with a clear appreciation of their relative importance and their different degrees of probability. The data most open to criticism are the decimal variation curves on page 17, the treatments of the secular variation on page 27, and the construction of the isogonic lines in the first chart. The paper could be improved greatly by critical revision and the addition of some additional information. A notable omission is a comparison of the Bamberg Declinatorium. The two large charts are valuable in so far as they show the places of observation and the data but he regards the isogonic lines in the first chart, and even the lines of equal size, as of very doubtful value.

Discusses the results in Table II and notes that no particulars are given on how the observations were made or of what precautions were adopted. Discusses the observations at Murrat Wells and Wadi Moghariu, these results do not fit in at all with the author's isogonic curves but no critical comment is given. Discusses the results on pages 26-31 noting that there does not seem to be any criticism or guidance from the author regarding these, beyond a general remark. To obtain reasonably certain mean data for a comparatively short period of years it is not enough to compare two isolated observations taken with different instruments, very likely at different hours of the day and seasons of the year and probably not exactly on the same site. Tee data on pages 30 and 31 depend mainly on observations by the author himself and d'Abbadie in 1885, some information as to the latter's instrumental outfit would be desirable. The discussion on page 34 shows signs of haste and could be improved by being re-written.

[Published in Proceedings of the Royal Society, 1902].

Endorsed on verso as received 20 June 1901.

Reference number

RR/15/214

Earliest possible date

18 June 1901

Physical description

Standardised form (type A), letter and note on paper

Page extent

7 pages

Format

Manuscript