14 SEVENTH REPORT—1837. 
been used was unfortunately broken in pieces in the carriage 
from London to Portsmouth by mail. It had been Capt. Liitke’s 
intention to have vibrated the needles at Portsmouth before his 
departure, and again at the same spot on his return from the 
Pacific; so that all the observations of his voyage with each 
needle might have been comparable with its rate at Portsmouth. 
The accident which prevented the execution of this purpose, 
and rendered the series of observations much less complete than 
it would otherwise have been, is much complained of both by 
Capt. Liitke and M. Lenz. In consequence of this accident, it 
was not until the arrival of the Siniavin at Kamtschatka that 
the needles could be vibrated at a station to which they were 
subsequently brought back ; and out of 52 stations, there are 
only 18 which were observed at during an interval in which 
anything is known by observation of the steadiness of the mag- 
netism of the needles. They were vibrated at three different 
dates at the harbour of St. Peter and St. Paul, viz.on Septem- 
ber 30, 1827, June 6, 1828,and October 9, 1828. Their changes 
of rate in the intervals were small, but not proportionate. 
Corrections are computed and applied at all the intermediate 
stations in the usual manner. M. Lenz has employed the rate 
of change of each needle, deduced from the first and second 
times of vibration at St. Peter and St. Paul, to furnish correc- 
tions for the stations observed at antecedently to Capt. Liitke’s 
first arrival at Kamtschatka; of these the land stations are 
Rio de Janeiro, Concepcion, Valparaiso, Sitka and Unalaska. 
For a single station (Manilla) observed at subsequently to the 
final departure from Kamtschatka, M. Lenz has used the rate 
of correction deduced from the second and third times of vibra- 
tion there. 
The times of vibration were derived on all occasions from the 
mean of 250 consecutive vibrations, commencing with an arc 
of 30° and ending usually about 10°. M. Lenz has not consi- 
dered it necessary to apply a correction for the ares. The value 
of the correction to a mean temperature was determined for 
each needle by observations made at St. Petersburg at the con- 
clusion of the voyage. For four of the five needles the correc- 
tion was as usual additive to the time for temperatures below 
the standard, and subtractive for those above it; but one 
needle, rhomboidal in shape, exhibited the anomaly of a de- 
crease of force in the colder temperatures, fully as great as the 
increase shown by any of the others. The observations appear 
to have been very carefully made,—were repeated four times,— 
and include a difference of temperature of 20° Reaumur. A 
similar anomaly has been noticed, if I remember rightly, by M. 
a ee ee Pe 
e Ago 
