276 SCOTT'S LAST EXPEDITION [May 
out of doors ; he allows me to rub him and push him about 
without the slightest protest and scampers about me as 
I walk abroad. He is a strange beast— I imagine so 
unused to kindness that it took him time to appreciate it. 
Tuesday, May 16.— The north wind continued all night 
but dropped this forenoon. Conveniently it became calm 
at noon and we had a capital game of football. The light 
is good enough, but not much more than 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 f- 0 th the refinement of measure- 
ment 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 
