REPORTS OF RESEARCH COMMITTEES. 
REPORT OF THE COMMITTEE 
ON 
THE MAGNETIC SURVEY OF NEW ZEALAND. 
THE survey has been continued by Mr. Coleridge Farr, with 
the assistance of Mr. H. F. Skey, and the number of 
stations at which observations have now been made is about 
180. 
The self-recording variation instruments have been in- 
stalled in a specially-constructed cellar in the Christchurch 
Botanic Gardens. The cellar has double walls, the outer 
wall being 1 foot m thickness and the inner 9 inches. 
These are separated by an air-space of 3 inches. The 
materials used in the concrete have been tested, and are 
non-magnetic, and the nails used in the wooden superstruc- 
ture and the door fastenings are all of non-magnetic metal. 
The roof also is of non-magnetic slate. The driving-clock of 
the instruments has been altered, so as to be capable of driv- 
ing the drums at either of two speeds, viz., one revolution in 34 
*hours or one revolution in | hour 36 minutes. This latter 
speed is a close approach to that desired by the International 
Magnetic ce-operation of 24 cm. per hour, viz., 23°25 cm. 
The arrangement, which has received a very thorough test- 
ing by being done continuously for about 80 hours, consists 
of an additional escape-wheel of two teeth only, separated by 
180°, working into an anchor, the teeth of which subtend 90° 
at the centre of the escape-wheel. To avoid excessive knock- 
ing, the driving-weight has been diminished, but is still 
amply sufficient. The alteration from one speed to the 
other can be effected easily in 10 seconds. 
A new magnetic absolute house has also been built, with 
two stone pillars of Oamaru oolite, capped with marble, and 
also office buildings, with a room attached for the Seismo- 
graph. A Milne horizontal pendulum, Seismograph No. 16, 
has been installed in the room. The beam has been ad- 
justed to have a period of 15 seconds. 
An order has been sent to England for apparatus for 
observations of atmospheric potential, and a complete set 
of meteorological instruments will shortly be installed. 
D 
