300 
NATURE 
[AY 13, IQI5 

matical honourmen turn to engineering, they cease 
to go further in mathematics, as they find it pays 
better to qualify as engineers. The average mathe- 
matician who is not essentially by nature and genius 
devoted to pure mathematics, finds that it is more 
to his advantage, and is a far less arduous task, to 
qualify in physics, chemistry, or engineering, where 
he may find an outlet for his energies outside the 
teaching profession. Problems of the class contem- 
plated by Mr. Paaswell depend essentially on a know- 
ledge not so much of engineering as of applied mathe- 
matics, such as rigid dynamics, hydrodynamics, 
thermodynamics and conduction of heat, and elasticity, 
up to the standard of the old part ii. tripos, which 
is a less attractive sequel to part i. than the engineer- 
ing tripos. Consequently applied mathematicians 
proper are few and far between, and a certain class 
of problems possessing no inherent difficulties is 
running to waste. Moreover, the few specialists in- 
terested in such work can only undertake it in the 
intervals between professional duties, often occupied 
with the teaching of engineering students of a very 
elementary standard. 
Messrs. Dickinson and Osborne, of the U.S. 
Bureau of Standards describe in the April issue of the 
Journal of the Franklin Institute what they term an 
“aneroid calorimeter.” It is an instrument in which 
equalisation of temperature is secured by means of 
the thermal conductivity of copper instead of by the 
convection of a stirred liquid. The calorimeter de- 
scribed, which consists of a thick walled cylindrical 
vessel of copper in the walls of which are embedded a 
coil of resistance wire to supply heat electrically, and 
a platinum resistance coil for use as a thermometer, 
has been found useful over a wide range of tempera- 
tures, and is applicable to a variety of problems. For 
use at low temperatures the calorimeter is mounted 
in a jacket surrounded by a bath of gasoline, the 
temperature of which can be controlled thermo- 
statically to within a few thousandths of a degree at 
any temperature between —55° and +40° C., or 
can be changed rapidly in order to keep it the same 
as that of the calorimeter when heat is being supplied 
to the latter. A series of check experiments on the 
specific heat of water shows the order of reproduci- 
bility of results which can be obtained to be 1 part 
in 2000. 
A NOTE on radiation pyrometers and their character- 
istics, by G. K. Buyers and P. D. Foote has been 
communicated to the April number of the Journal of 
the Franklin Institute. It heralds the publication of 
a very complete paper which is to appear from the 
Bureau of Standards. Some twenty instruments have 
been examined, including all the ordinary types 
commonly met with in practice, such as the four due 
to Féry, and the Foster, Thwing, and Brown pyro- 
meters. It has been established that the Stefan- 
Boltzmann law, E=a(T*—T,"), is not in general, ex- 
cept by accident, obeyed exactly by any of the pyro- 
meters examined. The similar equation, E=aT*.T?-* 
in which } is slightly different from 4 (usually neglect- 
ing the T, term) is, however, obeyed with sufficient 
exactness by all total radiation pyrometers. The main 
NO. 2376, VOL. 95] 


factors which influence the value of the exponent b are 
the geometry and mechanical construction of the jn- 
strument; the value of b for twenty thermo-electric 
pyrometers ranged from about 3:5 to 4-5. The same 
instrument of the Féry type may have a different 
exponent according to its use with or without the 
sectored diagram for increasing the temperature 
range. 
A HIGH-CAPAcITy wagon for the South African rail- 
ways is illustrated in Engineering for May 7, together 
with another wagon of special design and 160,000 Ib. 
capacity, built for transport of whales. These wagons 
have been constructed by the Leeds Forge Co., Ltd., 
and are excellent examples of steel rolling-stock. The 
whale wagon is intended to carry whales over a special 
3 ft. 6 in. line a few miles in length from the point 
where they are brought ashore to the factory, where 
they are dealt with for the extraction of oil, etc., 
not far from Durban. The bodies are hauled on to 
and off the wagon by windlasses. The line is very 
uneven, and it has been necessary to design the 
wagon with six-wheeled bogies, so as to keep the 
axle-loads down to the required limits and ensure the 
necessary flexibility. 
SCREW pumps having blades like those of a 
steamer’s propeller, mounted on a horizontal shaft, 
are a feature of several large pumping installations 
in the United States, particularly for drainage and 
flushing work, where large volumes of water must 
be handled promptly and rapidly. The latest and 
largest installation of screw pumps is at New Orleans, 
and is described in the Engineer for May 7. This 
installation is used in removing the storm-water 
drainage of the city and its surrounding district, lying 
between the Mississippi River and Lake Pontchar- 
train. Eleven screw pumps, 12 ft. in diameter, are 
now being built to supplement the present pumping 
equipment, so that the total pumping capacity will be 
7,240,000,000 U.S. gallons daily. The rapid removal 
of storm-water by pumping has a marked influence 
upon the sanitary condition, since it enables the 
ground to dry out more rapidly, and thus reduces the 
unhealthy conditions which result from damp and 
water-soaked ground in a large city. The total 
annual rainfall in the district ranges from 62 to 75 in., 
most of the heavy rainfalls being due to severe but 
brief storms. 

OUR ASTRONOMICAL COLUMN. 
METEORS FROM Hattey’s Comet.—Like the Perseids 
and Leonids, the meteors connected with Halley’s 
famous comet probably constitute a complete ring. 
They were first discovered by Lieut.-Col. Tupman 
while cruising in the Mediterranean in 1870, when the 
parent comet was near aphelion, and Prof. Alexander 
Herschel pointed out the significant resemblance be- 
tween the cometary and meteoric orbits. 
This year, in the early mornings of the first week in 
May, Mrs. Fiammetta Wilson, of Bexley Heath, 
observed, notwithstanding rather unfavourable 
weather, several splendid specimens of the Halleyan 
meteors. Two of these were also recorded by M. 
Felix de Roy, hon. secretary of the Société Astro- 
nomique d’ Antwerp, but now resident at Thornton 


