May 7, 1914] 
The comet is situated near the boundaries of the 
four constellations, Hercules, Vulpes, Cygnus, and 
Lyra. 
A CoNVENIENT COMPARISON . SPECTRUM.—For _ the 
study of both terrestrial and celestial spectra, it is 
useful for many purposes to photograph a comparison 
spectrum alongside the spectrum under investigation. 
The spectrum of iron is most generally used as the 
lines are well distrubuted along the spectrum, are 
sharp, and their wave-lengths are accurately deter- 
mined. The iron, however, may not be pure, so 
several strange lines may appear in the spectrum, and 
these have to be investigated. Dr. Joseph Lunt, in 
searching for a convenient means of obtaining the 
spectrum of cyanogen has incidentally found that the 
spectrum of lead pencils gives an extremely fine set of 
lines, very sharp, well distributed along the spectrum, 
exhibits a remarkable constancy of spectroscopic com- 
position, and consists of lines which are almost with- 
out exception present in the solar spectrum, the wave- 
lengths of which have been well determined. The 
account of this investigation on the spectra of 
graphites and lead pencils is given in vol. x. of the 
Annals of the Cape Observatory, part iv., and should 
be read by all those who work with the spectroscope. 
A plate reproduces the lead pencil spectrum from 
\ 4071-91 to Aq742-98. The sharp metallic lines are 
for the most part due to iron, titanium, vanadium, 
chromium, and the alkaline earths, barium, strontium, 
and calcium, while the spectrum shows also the pre- 
sence of the rarer elements, gallium, scandium, and 
yttrium, as well as silicon, magnesium, and man- 
ganese. The carrier of a lead pencil thus possesses a 
small portion of the very rare elements gallium and 
scandium. 
Report OF Harvard COLLEGE OBsERVATORY.—The 
report of the director of the Astronomical Observatory 
of Harvard College for the year ending September, 
1913, gives one a good idea of the great field of work 
projected and of the large amount of work accom- 
plished during the past months. It is hoped that 
means will be found to concede to the director’s wishes 
stated in this report by increasing the income of the 
observatory, for the situation is not very satisfactory 
when, as Prof. Pickering states, ‘‘during the last 
twenty years the income of the University has more 
than doubled, while that of the observatory has 
diminished rather than increased.”” The report shows, 
in the first instance, the progress made in the Henry 
Draper memorial department, the revised Draper Cata- 
logue being the principal work. More than _ half 
the sky has been covered, ard 100,155 stellar 
spectra have already been classified. The 11-in. 
Draper telescope, in the hands of Prof. W. H. Picker- 
ing, has produced valuable results, among which may 
be mentioned the periodic changes in form of the 
discs of Jupiter’s satellites. The work of the Boyden 
department at the Arequipa Station, of the Blue Hill 
Meteorological department (recently transferred to Har- 
vard University), etc., are all briefly summarised, and 
indicate the wide range of activities. 
THE SCHILOWSKY GYROSCOPIC TWO- 
WHEELED MOTOR-CAR. 
LARGE two-wheeled motor-car, constructed from 
the design of Dr. Schilowsky, a Russian Doctor 
of Laws, by the Wolseley Tool and Motor Company, 
Ltd., was given a trial run in London last week. The 
car is a six-seated car, and it carried six people as it 
slowly made a circuit of Regent’s Park. The gyro- 
NO72323; VOL. 93) 
NATURE 
251 
scopic mechanism is placed in the cupboard under the 
middle four seats. This consists of a heavy gyrostat 
rotating at the moderate speed of 1100 revolutions 
a minute, and driven by an electric motor of 13 
horse-power. The axis is vertical, and it is mounted 
in a ring supported on transverse trunnions, so that 
it may tilt in a fore and aft plane. As the car is 
necessarily unstable on its two wheels, the gyrostatic 
ring must also be carried unstably for it to have 
corrective influence. ify as a’ ship; the ‘cay 
could have been carried stably, then the gyro- 
static ring would also have to be stably mounted. 
If one is stable and the other unstable then 
the gyrostat operates in the opposite sense to that 
intended. 
The unstably mounted gyrostat will not maintain 
the car in its upright position for long, as the pre- 
cessional oscillations increase in amplitude. Dr. 
Schilowsky counteracts this by an ingenious piece of 
mechanism. Driven by worm-gearing from the gyro- 
stat axle are two spur wheels, each just out of gear 
with a segmental rack, but capable of being brought 
into gear by a heavy pendulum which feels any tilting 
of the car away from the dynamical vertical, This 
is only allowed to engage at such times as the gyro- 
stat ring is approaching the neutral position. During 
this time the engagement causes a hurrying of the 
precession and a consequent steadying of the motion. 
At the moment the neutral position is reached the 
pinion and rack are disconnected by a snap mechan- 
ism reminding one of that used for closing the valves 
of a Corliss engine. One pendulum controls the 
engagement when the gyrostatic ring is approaching 
the neutral position from one side, while the other 
effects the control on the other side of the neutral 
position. Either alone might be used, but the two 
alternate with one another and maintain a more con- 
tinuous control. It is a curious fact that the control- 
ling mechanism is more easily adjusted so as to main- 
tain the equilibrium of the car when it is turning in 
the opposite direction to the rotation of the wheel. 
For turning in the same direction more exact adjust- 
ment is necessary. A working model railway on this 
system has been presented by Dr. Schilowsky to the 
South Kensington Museum, where it may be seen 
by anyone interested. 
The car weighed three tons, having been designed 
for running on a rail, while the engine was one of 
the maker’s standard 16-h.p. engines. This was in- 
sufficient in power to drive the heavy car, as well as 
the motor of the flywheel, more than about four miles 
an hour. At this speed and at rest or moving back- 
wards the car maintained its position with passengers 
jumping on or off. When a new load was applied 
to one side the car moved almost imperceptibly so as 
to raise it and maintain the centre of gravity over the 
line of support as has already been made familiar by 
Mr. Brennan with his monorail. 
It will be interesting to see how the car behaves 
when a more powerful engine is fitted and higher 
speeds are possible. The inventor is, of course, aware 
of the very great couple, ordinarily resisted by the 
four-wheel support of the motor-car when ordinary 
curves and speeds are negotiated together, which he 
will have to contend with in like circumstances. The. 
demonstration in the Regent’s Park did not show that 
the gyrostatic control then existing would be sufficient 
for this, but it did show, and that perfectly, that the. 
first step has been successfully accomplished. It may 
be worth while to add that the bicycle balance is not 
used, the gyrostatic control being independent of speed 
or direction of motion. 
CC; Vi. Boys: 
