184 
NATURE 
[APRIL 15,. 1915 

the plates, which are cross connected, as in the 
quadrant electrometer. Resonance is secured by ad- 
justing the tension or length of the suspension, and 
the deflections are read by the telescope and scale 
method. With the air pressure reduced to 0-005 mm. 
of mercury the deflection per volt at 50 cycles per 
second is 6 em. on a scale at a metre distance, and 
the least current the instrument will detect is 1o~** 
ampere. The behaviour of the electrometer agrees 
very closely with the theory developed by the author. 
TecHNoLocic Parer No. 41 of the Bureau of 
Standards, Washington, by R. S. McBride and 
J. D. Edwards, deals with the lead acetate test 
for hydrogen sulphide in illuminating gas, and is of 
interest here, as sulphuretted hydrogen is now the 
only impurity in coal gas officially controlled. It is 
pointed out that the various modes of testing in use 
are not all directed to the same end, since some of 
the tests are designed to detect as small traces of 
hydrogen sulphide as possible, while others aim to 
give a negative test when a permissible amount is not 
exceeded. The previous work of W. J. Dibdin and 
R. G. Grimwood, R. Forbes Carpenter, and C. J. 
Ramsburg, is described and criticised, and details of a 
new set of experiments are given in which some of 
the errors ascribed to the earlier work are avoided. 
The variations due to the kind of paper, concentra- 
tion of lead acetate solution, preparation and condition 
of the paper, humidity of the gas, rate of flow and 
time of exposure, and the various forms of testing 
apparatus have been studied separately. Based on 
these results a method is recommended for use which 
is claimed to be quick and convenient, and gives 
reproducible results. 
A RECENT publication among the Oxford pamphlets 
is by Prof. J. O. Arnold, the professor of metallurgy 
in the University of Sheffield, entitled ‘‘ British and 
German Steel Metallurgy.’’ It was inspired, as the 
opening sentences show, by an article by Prof. Rein, 
of the University of Vienna, on ‘Civilisation and 
‘Kultur.’’? The pamphlet attempts to show (1) that 
German steel metallurgy owes far more to British 
inventors than British steel metallurgy owes to German 
inventors, and (2) that the steel department of the 
University of Sheffield has done work greatly superior 
to that of the corresponding department at Charlotten- 
burg. The following claim bearing on the latter 
thesis may be quoted from the pamphlet as typical 
of the style:—‘‘There are about twenty-nine con- 
stituents or sub-constituents of steel and iron. Of 
these, twenty-six have been discovered in Sheffield, the 
steelopolis of Great Britain; three in Middlesbrough, 
its ironopolis; and the record of Charlottenburg in 
this branch of research is absolutely blank.” We 
confess to regretting that the author has by this 
publication placed himself in the category of those 
who desire to minimise the debt that British science 
owes to German science. It would have been better 
if the task had not been attempted. 

Tue Engineer for April 9 directs attention to some 
absurd British methods of dealing with drawings re- 
NO. 2372, VOL. 95] 


ceived from consulting and other engineers on the 
Continent. In a recent instance, detail drawings 
received from abroad showed particulars all dimen- 
sioned metrically. The British drawing office, with 
much care, translated these dimensions into feet, 
inches, and fractions. Some typical examples of the 
results are noted: A bolt circle diameter of 418 mm. 
was translated to 16;5 in. + gf in.; 21 mm. 
clearance holes for black bolts became 4? in. + 
gy in. The chances of mistake in this method are 
considerable, and include translation errors, errors in 
ordering drills to such odd sizes, and errors in mark- 
ing off and making jigs and templates. In addition, 
trained mechanics have an ingrained fear of dimen- 
sions in sixty-fourths, and will spend much more 
time over these figures than over even numbers. The 
commonsense method is to give the workmen the 
drawings in metric system and supply them with 
metric rules. In view of the continually increasing 
demand from the Continent for material manufac- 
tured in this country, it is probable that we are on 
the eve of a very considerable extension of the use of 
the metric system in our workshops and factories. 
THe ninth report of the Royal Commission on 
Sewage Disposal has now been issued. Part ii. 
consists of a brief statement relating to the disposal 
of sewage in rural areas where sewers are not avail- 
able. The question as to whether a rural committee 
should adopt some dry method of disposal, or provide 
sewers and purification works, depends upon whether 
a water supply is laid on to the houses or not. If it 
is, a sewerage system is almost inevitable; but if 
not, then dry closets may be used satisfactorily under 
proper supervision. In a minority report on this sub- 
ject Sir William Ramsay appears to favour the exten- 
sion of dry systems, even when a water supply is 
laid on to houses, mainly on the ground that the 
valuable nitrogen of domestic sewage ought to be 
returned to the soil. Engineering for April 9, com- 
menting on the report, sympathises with Sir William 
Ramsay’s desire to put some check on such a waste; 
but points out that epidemic disease amongst the 
people involves a greater waste, and there is no deny- 
ing the beneficial effects on health which follow the 
acquisition of a pure and abundant water-supply, or 
the evils which, literally, lie at the door of ill-managed 
“dry ’’ systems. 

OUR ASTRONOMICAL COLUMN. 
ComeT t915a (MeLLisH).—The following ephemeris 
of Comet Mellish is a continuation of that calculated 
by Messrs. Braae and Fisher-Petersen, ana printed in 
a circular issued by Prof. Elis Str6mgren :— 
As 4. (true) Decl. (rue) Mag. 
mie s. ° ‘ 
April 20 18 24 59 —5 36:0 
22 27, 16 6)-13'6%) a= e 
24 29) 02 eee 6 544 , 
26 TROP MEANY TU ngs Safety Sig. hl 
The comet is moving in the constellation of Aquila, 
and lies to the west of A Aquila and is about equi- 
