. 224 REPORT—1896. 
thickness of the needle, DE, of the vertical lever. The vertical axis, M, 
consists of a fine steel needle, the lower point of which rests in the 
conical cavity of a small glass cup fixed to the plate, P. The axis, M’, is 
exactly similar, but the lower end rests in a glass cup, whose height above 
the plate, P, can be adjusted by a screw. The levers are provided with 
<ounterpoises, N, N’, N’. The needle, DE, of the vertical lever passes 
through the slits, L, L’, and thus any displacement of the end, E, is 
decomposed by the horizontal levers into two components at right angles 
to one another. 
At the free ends of the aluminium arms of the levers, fibres of glass are 
fixed at right angles to them with melted wax. In the apparatus after- 
wards erected at Padua (to which fig. 14 refers), these glass fibres are 
replaced by broad but thin strips of glass, the terminal parts being drawn 
out as fibres. 
In the horizontal levers the length of the long arm is about five times 
that of the short arm ; the movements of the wall supporting the apparatus 
are therefore magnified about eighty times. 
The smoked paper on which the records are made is a continuous 
strip, and is driven by a drum which revolves by clockwork. The drum 
is placed so that the pens rest on its highest horizontal generator, and the 
fibres are made of such thickness and length that, with the slight friction 
to be overcome, they do not bend. To diminish their friction they are 
fused at the tip ; the smooth surface of a very small sphere of glass thus 
slides on the smoked paper. To equalise the friction of the two pens, that 
of the pen K is first regulated by raising or lowering the support on 
which the plate P rests by means of the levelling screws with which it is 
provided. The contact of the other pen is then adjusted by moving the 
glass cup on which the axis M’ rests. The clock which drives the drum 
may be of any kind, but, in order to measure the time, a chronograph is 
connected with a good pendulum clock which closes an electric circuit, 
and thus causes a stroke to be made on the paper every minute. At each 
hour a double mark is made. 
The strip of paper is unrolled at the rate of about 2 mm. a minute. 
The pens leave on the paper a fine but very clear trace. When heavy 
carts pass by the University buildings the lines are simply widened, the 
lampblack being completely carried away. In the case of earthquake 
movements, however, the separate oscillations are clearly perceptible, 
though the more rapid ones are only to be seen with the aid of a lens. 
Fig. 15 reproduces the diagram obtained at Siena of the Japanese earth- 
quake of March 22, 1894. The toothed line in the middle shows the 
strokes which mark consecutive minutes. This figure may be compared 
with the record of the same earthquake obtained by means of the horizontal 
pendulum at Nicolaiew.! 
Beside the microseismograph above described, Professor Vicentini has 
recently erected a new instrument at Padua, designed, not for obtaining 
the times of the different phases of a disturbance, but for determining 
with greater exactness the direction in which the movement takes place. 
The mass of the new pendulum is 100 kg., and its length 3:36 metres. It 
contains a vertical amplifying lever, like the first instrument, but for the 
horizontal levers a small pantagraph was substituted at Dr. Pacher’s 
suggestion. This is made of aluminium tubes, weighs about eight deci- 
' See Brit. Assoc. Rep., 1894, p. 156. 
