70 NATURE 
Jeffree, considers the strength of the pile to resist the 
various handling processes it has to undergo before 
being finally driven. From the diagrams given, the 
pile is subjected to a maximum bending moment of 
W(L—S8)?/8 in.-lb., where W is the weight of the 
pile in lb. per inch run, and L is its length in inches. 
Expressions are given for the moment of resistance 
for the pile lying on the flat and also for one diagonal 
of As reliance is placed on the 
continuity of the concrete to protect the steel from 
the section vertical. 
corrosion, the author proposes to limit the stress on 
the steel to 20,000 lb. per square inch before driving 
the pile. Hair in the will thus be 
avoided. The article closes with a useful table giving 
the section moduli and limits of safe length for piles 
from 10 to 16 
reinforcement 
cracks concrete 
in. square with various amounts of 
in which the above-mentioned condi- 
tions are fulfilled. 
THE interest taken in the development of the Diesel 
engine was evidenced by the very large attendance 
at the Institution of Mechanical Engi s on Friday, 
March 15, when a paper was read by Dr. Rudolph 
Diesel. The author considers that England has the 
greatest interest in replacing the coal-wasting steam 
engine by the Diesel engine, as enormous savings can 
be thus effected in her most valuable treasure—coal. 
As tar and tar oils are from three to five times better 
utilised in the Diesel engine than coal in the steam 
engine, a more economical way of using coal 
obtained if, instead of being burnt in boiler furnaces, 
is 
it is first converted into coke and tar by distillation. 
Coke is useful for metallurgical and other general 
heating purposes; from a part of the tar the valuable 
by-products are first extracted, and undergo further 
processes in the chemical industry, whilst the tar-oils 
and combustible by-products, together with a great 
part of the tar itself, are burned in the Diesel engine 
under extraordinarily favourable conditions. For river 
vessels in the colonies, the Diesel engine is very suit- 
able. Questions regarding the limiting dimensions of 
cylinders, influenced by the strength of the metal and 
by the heat produced, were raised in the discussion. 
A xist of the publications of the Carnegie Institu- 
tion of Washington has been received. Copies of 
each publication, except the ‘‘Index Medicus,” are 
sent gratuitously to a limited list of the greater 
libraries of the world, while the remainder of the 
edition is on sale at a price sufficient only to cover 
the cost of publication and carriage to purchasers. 
Brief descriptions of the contents of the more 
important volumes add greatly to the value of the 
catalogue. 
OUR. ASTRONOMICAL COLUMN. 
Nova GEMINORUM NO. 2 \ second telegram, 
which arrived from Wiel too late for us to publish the 
correction last weelx, announces that Enebo’s 
new star is near @, not Geminorum The new 
position, being at a greater altitude, is better for 
observation than the earlier one on March r= the 
nova was quite easily found o th yuth and 
east of 6 Geminorum; the accompanying chart shows, 
NOR M2 2ie2,, 
VOL. 
| 
| 
| 
{MARCH 21,, 1912 
Nova 
discovered photographically by 
approximately, the position, and also that of 
Geminorum No. 1, 
Prof. Turner in 1903. 
Greenwich measures made on March 15 give the 
position as 6h. 49m. 14s., +32° 15’. Photographs of 
the spectrum show the hydrogen lines, both dark 
and bright, with other bright lines, and the magni- 
tude was estimated as about 4-0; observations made 
independently at Chichester and Birmingham show 
that the star, 
fourth 
later on March 15, was fainter than the 
by 
magnitude. Later observations, several 
observers, show that by Monday night the star was 
certainly fainter than magnitude 5. 
We learn from Prof. Fowler that a spectrum 
secured during a short, clear interval on Friday night, 
at the Imperial College of Science, shows the spec- 
trum to be similar to those of Nova Persei and 
Aurige in the earlier stages. Although the dispersion 
is small, the bright and darlx hydrogen series are 
easily seen. 
OBSERVATIONS OF Mars.—With the to-in. refractor 
of the Urania Observatory, Herren Janssen and 
Andersen made a number of observations of Mars 
during the months September to December, 1911. An 
eosin-red glass was at times employed to accentuate 
the contrast between the different parts of the planet’s 
surface. While the ‘‘coastlines’’ generally were very 
well defined, the islands in the **Stidmeere ” were very 
pale; the details of the observations are shown on a 
chart accompanying the paper in No. 4561 of the 
lstronomische Nachrichten. Twenty-nine “canals” 
were seen, but none was seen doubled. 
Tur CONSTITUTION OF THE RING NEBULA IN LyRA.— 
In a paper recently communicated to the Heidelberg 
Academy, Prof. Max Wolf finds that certain radia- 
tions are emitted only by well-defined portions of the 
Ring Nebula, the line A 4686 arising solely from the 
central dark space, while the lime A 3729 occurs 
chiefly towards the outer edge of the bright ring; 
this differentiates these two radiations from the 
others in the nebular spectrum, and, according to 
Prof. Wolf, probably denotes different substances 
with widely differing atomic weights. Dr. Nichol- 
son’s failure to account for these two lines in his 
recent theoretical discussions of the spectrum of the 
hypothetical ‘nebulium ” consequently 
affords no indication that his theory is untenable. 
substanc 
