good enough, for this game.

Had some instruction from Wright this morning on the electrical
instruments.

Later went into our carbide expenditure with Day: am glad to find it
sufficient for two years, but am not making this generally known as
there are few things in which economy is less studied than light if
regulations allow of waste.

Electrical Instruments

For measuring the ordinary potential gradient we have two
self-recording quadrant electrometers. The principle of this instrument
is the same as that of the old Kelvin instrument; the clockwork
attached to it unrolls a strip of paper wound on a roller; at intervals
the needle of the instrument is depressed by an electromagnet and makes
a dot on the moving paper. The relative position of these dots forms
the record. One of our instruments is adjusted to give only 1/10th
the refinement of measurement of the other by means of reduction in
the length of the quartz fibre. The object of this is to continue the
record in snowstorms, &c., when the potential difference of air and
earth is very great. The instruments are kept charged with batteries
of small Daniels cells. The clocks are controlled by a master clock.

The instrument available for radio-activity measurements is a modified
type of the old gold-leaf electroscope. The measurement is made by the
mutual repulsion of quartz fibres acting against a spring--the extent
of the repulsion is very clearly shown against a scale magnified by
a telescope.

The measurements to be made with instrument are various:

The _ionization of the air_. A length of wire charged with 2000 volts
(negative) is exposed to the air for several hours. It is then coiled
on a frame and its rate of discharge measured by the electroscope.

The _radio-activity of the various rocks_ of our neighbourhood;
this by direct measurement of the rock.

The _conductivity of the air_, that is, the relative movement of
ions in the air; by movement of air past charged surface. Rate of
absorption of + and - ions is measured, the negative ion travelling
faster than the positive.

_Wednesday, May_ 17.--For the first time this season we have a rise
of temperature with a southerly wind. The wind force has been about
30 since yesterday evening; the air is fairly full of snow and the
temperature has risen to -6 deg. from -18 deg..

I heard one of the dogs barking in the middle of the night, and on
inquiry learned that it was one of the 'Serais,' [2