440 EF. Hungerford—Observations on Snow and Ice 
pressure was brought to bear by means of a square wooden plun- 
ger, driven by an iron screw, which worked in a wooden frame. 
‘or these contrivances, which were, in many respects, very 
useful for earlier observations, I afterwards substituted a much 
more convenient iron press. The details of this press, it is 
hardly necessary to describe. e snow was packed in a 
cast iron cylindrical mould, having a smooth ee es bore in 
the center one inch in diameter. The bore is three and one- 
half inches deep and of smooth finish, to laine the friction of 
the snow. Into this bore works a plunger, also of iron, nicely 
rods which are the uprights of es press. Into the upper side 
of this head the lower end of the iron screw projects ba 
in brass fittings—while the screw itself runs through an upper 
iron cross bar. By this means the plunger with its head can 
be carried down into the mould smoothly, by a slow motion of 
thescrew. ‘To the head of the screw a wheel was attached to 
which the power was applied by means of a cord passing over 
s 
not By this meaus a reasonably continuous and regulated 
pressure could be brought to bear upon the snow in the moulds. 
These moulds were split vertically through the middle, and were 
held together by a stout iron ring, which could be struck off 
with a blow of a hammer, When opened, the moulds exposed 
a vertical section of the little cylinder of ice resulting from the 
pressure. ‘The slight differential motion of the pressed mass, 
on each side of the plane along which ms mould was split, left. 
a corresponding plane of easy cleav in the resultant mass. 
Aside from the convenience of this fe arrangement, it gave 
me the marees that the conducting power of the iron, as 
exposed to low temperature, would help to prevent the accu- 
mulation of Sent from the gradually increased pressure and 
slow downward motion of the plunger. The snow in the inte- 
rior of the mould savoger ire be kept very close to the tempe- 
rature of the externa 
am under great obligalions to my friend, Mr. Robert W. 
Willson, Assistant Astronomer in the Observatory i in New Ha- 
ven, who has very kindly assisted me to obtain ai Bge:| 
power of this little ate press by actual trials. We have tested 
the force exerted at the lower face of the plunger Pies aves five 
pounds of power up em fifty applied at the wheel. ‘The obser- 
vations, made and repeated by us interchangeably, to correct the 
sonal error, have resulted in a very even rate, so that we 
abled to extend the rate up toa er of sixty pounds at the 
wheel, which is the highest used. Te ean therefore insert in all 
