APRIL 29, 1915| 
NATORE 241 

the year—allowing for failures to register—being 
about 40,000. One July day. is credited with the 
enormous number of 8604. The winter months—the 
station is in 4r° 52’ S. latitude—showed the largest 
numbers. No clear connection was established with 
barometric pressure, temperature, wind, humidity, or 
cloudiness. Rain fell on almost all the days of greatest 
frequency; but 107 days of the mid-winter months, 
May to August, were rainy days, so no inference could 
be drawn. In winter there seemed a distinct increase 
of atmospherics on in which thunder was 
recorded, but in summer this was not the case. The 
data, however, as to distant thunderstorms do not 
seem to have been altogether adequate, owing to 
paucity of stations. <A series of tables shows the 
number of atmospherics recorded for each hour of 
each day from April to December. For the first 
three months of the year only daily totals are given. 
days 
Tue damage done to telephone systems in the tropics 
by animal life was mentioned in the course of a paper 
and discussion published in the last number of the 
Journal of the Institution of Electrical Engineers. 
The culprits are of all sizes, from elephants and 
giraffes down to white ants and spiders. Mr. W. LI. 
Preece described how the giraffes in East Africa, when 
their progress is impeded by a telephone line, have 
not the sense to draw back or “duck” their heads, 
but push on and carry the wires with them—and some- 
times the poles too. The only wood which is respected 
by white ants is tealx, and instrument cases should be 
made of this or of metal. A telephone instrument 
was shown which had been persistently used as a hive 
by a swarm of * bee-lilke insects,’ who entered by the 
slot for the switch-hook, and formed a comb inside 
which they re-formed as often as it was cleared away 
by the engineers. Instruments and also insulators 
have an attraction for spiders, and are often rendered 
hors de combat by their webs, but apparently they 
leave glass insulators alone, although much trouble 
is experienced in this connection with the ordinary 
porcelain type. The webs get coated with dew, and 
the insulation resistance is brought down to a few 
ohms only. Sir John Gavey said that the trouble was 
not always caused by the spiders building their webs 
in the insulators themselves, but that, in the Argentine 
these insects breed in millions in the pampas grass; 
as soon as they come to life they spin a single web, 
which the wind carries across the country, and veils 
of these webs sometimes collect from pole to pole and 
cover the whole of the wires. Cases of beetles boring 
holes in lead cable and laying their eggs in them have 
also been well authenticated, and Mr. J. E. Kingsbury 
had an instance of moths making their home: in a 
multiple switchboard cable. Finally, owing to the 
troubles which not infrequently occur in bringing 
difficult local conditions into line with the requirements 
of home administration, one speaker said that the 
engineer in charge ran the risk of becoming a mere 
“red-tape worm ”’ himself. 
A Lone and important paper on the compressive and 
flexural properties of a series of Scottish building and 
road stones was presented by Mr. Robert Boyle to the 
Institution of Engineers and Shipbuilders in Scotland 
NO. 2374, VOL. 95] 



‘on March 23. 
Twenty varieties of stone, consisting 
of 211 specimens, were tested. The principal deduc- 
tions from the tests on Scottish sandstones as 
follows. The average ultimate compressive strength 
tested dry, at right angles to the 
bedding, was 479-4 tons per square foot. The average 
percentage difference in individual results for com- 
pression tests varied from 4-3 to 50:3, with a mean of 
the averages of 23-2 for sixteen varieties. The average 
percentage differences in individual results in bending 
tests were much less than in compression, whether 
dry or saturated. Plaster of Paris coating appeared 
to have no effect on the ultimate strength of the stone. 
The crushing strength, hardness, and specific gravity 
vary approximately as the lime and magnesia com- 
pounds, and the crushing strength and specific gravity 
as the percentage of iron oxides. 
are 
for specimens 
The crushing and 
bending strengths vary directly as the specific gravity. 
The percentage ratio of absorption of water and the 
percentage porosity diminish as the specific gravity 
increases, 
Engineering for April 23 gives an account of the 
Brooks Aqueduct, Alberta, Canada. This aqueduct 
forms part of the irrigation works of the eastern sec- 
tion; last year construction on this section was com- 
pleted for the irrigation of 440,000 acres. The aque- 
duct is the first in which the hydrostatic catenary 
has been adopted for the shape of the water section; 
it has a length of 10,500 ft., and a capacity of 
goo cu. ft. per second, and is the longest aqueduct 
yet constructed for carrying such a large quantity of 
water. The reason for adopting the hydrostatic cate- 
nary was that the total fall was limited to 4-85 ft. in 
10,000 ft., and that consequently it was necessary to use 
this head to the very best advantage. The water section 
chosen is the most suitable, as it gives a maximum 
hydraulic radius for the given area, and a consequent low 
friction head. Structurally it is economical, for, 
when full, the shell is in simple tension and free from 
bending moments and shears. The idea of using this 
catenary for the water section is due to Mr. H. B. 
Muckleston, assistant-chief engineer, and it was 
adopted after experimenting with a full-sized model. 
WE regret that by an accident at the printing office 
after last week’s Nature had been passed for press, 
the letter on ‘The ‘Green Ray ’ at Sunset,’’ appeared 
on p. 204 without the name of our correspondent, 
Mr. T. B. Blathwayt. 


Comer i915a (MeELiisn).—The following ephemeris 
of Mellish’s comet (19154) is published in Astro- 
nomische Nachrichten, No. 4796, and communicated 
by Dr. J. Fischer-Petersen :— 
eae (true) y Dec. (true) Mag. 
sp Ms Se 5 } 
April 30... 18 43 48 —10 44-6 a 
Mayan 5. 40 54 Ir 56:8 
40a Pben fo) te! ey iy Aoyy - Song (oe) 
(G9 ae ae} air —14 46-2 
The comet is still situated in the southern portion 
of the constellation of Aquila, and lies towards ‘the 
south-east of the stars 2 and 3 Aquilz. 
A note in the Astronomische Nachrichten, No. 47095, 
