188 
PROCEEDINGS OF SECTION A. 
at Alexandria, and Captain C. Orde Brown, E.A., at Mokattam. 
Transits were recorded by eye and ear at these two latter places. All 
galvanic signals were sent by hand, and observed by eye and ear. 
The operations were executed in November, 1874, on the four nights, 
14th, 15th, 21st, and 22nd. The personal equation in observing 
transits between Mr. Criswick and Captain Brown was determined 
before and after the longitude operations, and varied from 0 025 sec. 
to 0’655 sec.— (8) page 288. 
(b) Alexandria -Mokattam. — (8) On the same four nights, 14th, 
15th, 21st, and 22nd November, Mr. Hunter, at Alexandria, made transit 
observations with a portable transit instrument, in addition to exchange 
of signals with Mokattam. His station, which was on the roof of the 
Hotel de TEurope, does not seem to have offered the necessary 
stability for delicate work. Dr. Gill remarks of this station — (7) 
page 63 — “The observer had to abstain from movement during each 
complete observation, otherwise the level was disturbed by the change 
of his position.” The personal equation of the two observers was 
determined after their return to England. At Alexandria the 
chronometer had to be carried to the telegraph office for exchange of 
signals, which was at a distance of about live minutes’ walk. 
(c) Greenwich- Berlin. — Eesult of several determinations — (9) 
page 490. 
(d) Berlin- Malta. — Observers : At Malta, Dr. Low, chief of 
the German Expedition of the Transit of Venus, 1874, to Mauritius; 
at Berlin, the astronomers of the Observatory, Drs. Becker, Auwers, 
and Knorre. Dr. Low made time observations with a portable transit 
instrument, recording by the eye and ear. Galvanic signals exchanged 
by hand on six nights in 1875, March 10, 11, 12, 13, 14, and 15. Personal 
equation well determined. Signals satisfactory — (9) page 300-393. 
(<?) Malta- Alexandria. — Observers: Dr. Low at Malta, Dr. Gill 
at Alexandria, same station as Mr. Hunter’s. Dr. (Jill made his time 
determinations with an altazimuth. Operations repeated on the 
nights of March 10, 11, 12, 13, and 14 (1875). Personal equation of 
these observers, well determined. 
The chronometers had to be carried to the telegraph station for 
exchange of signals, as in the case of ( b ) — (9) page 300-320. 
(/) Berlin- Alexandria. — Direct measurement made on February 
28, March G, 7, 10, 12, 13, and 14 (1875). Personal equations of the 
observers, known through Dr. Low ; the observers being Dr. Gill at 
Alexandria, aud the astronomers of the Observatory at Berlin. This 
value was deduced by Dr. Copeland. It is remarked in (9) that 
the signals were unsatisfactory, and the combination of the two 
intervals (d) and ie) was adopted in preference of the direct value — 
(9) page 320-348. 
(/;) Berlin- Alexandria. — Same operations as in (/). Value 
deduced by Dr. Auwers — (7) page 60. 
The three values for the longitude of Alexandria are — 
h. m. sec. 
By the combination — ( a) — (b ) ... ... 1 59 33’69 
O)+(<0 + 0) 1 59 33-827 
(«) + H(/) +(/.)}••• 1 59 33-750 
