SCIENCE. 
7 1 
And, in addition to this, more variation is to be expected in 
the strength of the lugs, as some at least were admitted to 
be of bad manutacture, and when the pier was most severely 
strained it would be some of the worst lugs in the lower 
tiers that would be the first to yield ; thus the samples taken 
for testing would not be likelv to embrace specimens of 
the lowest strength, as these would probably have already 
given way. 
Again, it does not appear necessary to assume a wind 
pressure of 40 lbs. per square foot to ensure the destruction 
of the pier ; the stresses above mentioned are due merely 
to the statical pressure, and it can hardly be denied in the 
face of the evidence respecting the details of the structure 
that there would be a great deal of motion due to backlash 
over and above the elastic yielding of the material. Thus 
a much lower pressure would produce the effects calculated 
for one of 40 lbs. per square foot. 
The principal conclusions arrived at by the court are that 
there is no indication of settlement in the foundations, that 
the wrought iron employed was of fair strength, though not 
of high quality as regards toughness, that the cast iron was 
fairly good, that the main girders were of sufficient strength, 
and that the iron piers, though strong enough to sustain the 
vertical load, were insufficient to resist the lateral action of 
heavy gales from the weakness of the cross bracing and its 
fastenings; that the railway company did not enforce the 
recommendation of General Hutchinson by limiting the 
speed of trains over the bridge to twenty-five miles per 
hour, much higher speed being frequently run ; that while 
of opinion that the fall of the bridge was occasioned by the 
yielding of the cross bracing and fastenings, it might possi- 
bly have been due to the fracture of one of the outward 
leeward columns. 
Colonel Yollard and Mr. Barlow conclude by stating 
“ that there is no requirement issued by the Board of Trade 
respecting wind pressure, and there does not appear to be 
any understood rule in the engineering profession regard- 
ing wind pressure in railway structures; and we therefore 
recommend that the Board of Trade should take such steps 
as may be necessary for the establishment of rules for that 
purpose.” 
Mr. Rothery, in his independent report, while stating that 
there is an entire agreement between himself and his col- 
leagues in the conclusions arrived at from the evidence, 
goes further than they, and unhesitatingly apportions the 
blame among the different parties concerned. On the recom- 
mendation that the Board of Trade should establish rules 
providing for wind pressure, he differs from his colleagues, 
emphatically stating that it is for the engineering profession 
to make them, and evidently regards the superficial charac- 
ter of an official inspection as no great evil. 
Where French engineers have long adopted 270 kilo- 
grammes per square metre, and many English engineers, 
on the authority of Rankine, the equivalent 55 lbs. per 
square foot, while nearly the same figure is used in America, 
it seems strange that so much difference of opinion should 
be found to exist ; but one thing at least is certain, that the 
instruments at present in use for measuring wind pressure 
are exceedingly crude and liable to error, and that until 
these are improved and much increased in number there is 
little chance of being on the spot when these excessive 
pressures occur, or of truthfully recording them when met 
with. 
Respecting the transfer of these responsibilities to a 
Government Department, we believe that such apronstring 
policy would be fatal to the profession of the civil engineer ; 
we would rather see the Board of Trade Inspection, which 
at least is formal and superficial, relaxed than any attempt 
made to increase its efficiency. The medical profession 
does not require a fatherly department to watch over its 
operations or give an opinion on an amputation ; why chen 
should the engineering profession ? It cannot be too clearly 
understood that an engineering work cannot be success- 
fully carried out by mere rule of thumb or even by the 
copious use of “ Molesworth” or “ Rankine” ; each opera- 
tion is to some extent a physical experiment, subject to 
known laws, but under variable conditions. The physicist 
and the engineer have already to a great extent established 
the laws for themselves, but it remains for the scientific en- 
gineer to carefully watch their operation, and thus gain 
that practical experience which will enable him to deal with 
each special case as it arises. 
The conclusions we draw from the evidence and report 
are that the design of the piers was most imperfect, cheap- 
ness appearing to be the ruling element in every detail, a 
cheapness too that must have been completely delusive, as 
any money saved in first cost would soon, in such a rickety 
structure, have been swallowed up in maintenance. At 
nearly all points an absence of consideration for small de- 
tails is most apparent, indicating probably that these were 
intrusted to some subordinate, who failed to appreciate 
their importance. 
It is very far from our object in this article to hold up 
any particular individuals to blame for this disaster, but 
we should like to point out on whom the responsibility 
should rest if such a thing should occur again. 
It would be quite impracticable for the Board of Trade 
to exercise such supervision over the selection of the 
material and the execution and erection of a large work 
throughout its progress, as would render its certificate of 
any value ; we believe, therefore, that the undivided respon- 
sibility should rest on the engineer. Any dishonesty on 
the part of the contractor or his workmen — and we are 
sorry to believe this still exists in some cases — could be 
easily rendered hazardous by legal penalties. 
Doubtless with the keen competition of the present day 
things must be “ cut finer” than they used to be : but while 
we would remove any arbitrary restrictions imposed by 
Government on the judgment of those who ought to be best 
able to appreciate the particular conditions of their own 
work, we should be very sorry to see the introduction of 
flimsy structures or reckless traffic arrangements without it 
being understood on whom the responsibility rested in 
case of failure. 
A letter recently sent to Professor Plantamour, director 
of the Geneva Observatory, gives the details of a singular 
phenomenon observed at Bonneville on the 25th of April. 
It was noticed during a rain storm, that the drops of water 
falling upon dark clothes, linen, umbrellas, left a dirty 
yellow spot verging on brown. The matter was given over 
to M. de Candolle, for investigation, who found that the 
powder which colored the yellow rain, contained only or- 
ganic elements of vegetable origin. Observed dry, or in 
pure water, these ddbiis had mostly a yellowish color, but 
some were colorless. They were generally formed of cells 
of small diameter, upon the walls of which were granula- 
tions consisting of the finest particles of the pulverulent 
matter of the rain drops. The advanced state of disaggre- 
gation of all these vegetable debt is, did not allow of the de- 
termination of their origin ; but the minuteness of the cells 
seemed to indicate that they belonged to young tissues. 
Amongst the fragments, with form so varied and irregular, 
were found some spores of cryptogams, but no grains of 
pollenjwere met with. 
M. Dines has calculated that the amount of dew deposited 
on the ground in the course of a year would be represented 
by a layer of water about 40 millimetres (r.6 in.) in height, 
equivalent to 40 litres per square metre. 
The Royal Society of New South Wales now numbers 430 
members, exclusive of honorary and corresponding mem- 
bers. Mr. G. Bentham, Dr. Darwin, Prof. Huxley, Prof. 
Owen and Sir. J. D. Hooker have been elected honorary 
members, and Mr. R. Etheridge, jun., a corresponding 
member. The Clarke memorial medal for 1878 has been 
awarded to Prof. Owen, for 1879 to Mr. G. Bentham, and 
for 1880 to Prof. Huxley, for their contributions to palaeon- 
tology, botany and natural history of Australia. 
