132 
NATURE 
| Dec. 7, 1882 
late Tay Bridge may be interesting. I suppose that 
equal trains are upon the two bridges; and I assume 
that the force of the wind on the Tay Bridge train tore 
one pier from its foundation-attachment. (I imagine 
that the ruin of the bridge commenced thus). The 
height of the centre of the Tay Bridge train was about 
92 feet, and the momentum of the wind was, therefore, 
wind X train X 92 feet. (The reader will easily interpret 
my brief notation). To resist this there were three pairs of 
attachments to the foundation, with lever-widths of 10 
feet, 22 feet, 10 feet, respectively. So that, supposing 
the holding powers of each attachment the same, we 
must have had for momentum of resistance, one Tay- 
attachment X (10 + 22 + 10) feet. At the instant of 
breakage, this was equal to the momentum of the wind, 
orto wind X train X 92 feet. So that one Tay-attach- 
92 
42 
we treat the proposed Forth Bridge in the same manner, 
we must use, length of lever about 660 feet, and two pairs 
of attachments of the cantilever to the pier (if I read the 
plan correctly), at distances of 30 and 120 feet. And 
thus we shall have the equation at a moment of breakage. 
One Forth-attachment X (30+ 120)= wind X train X 
660 ; or one Forth-attachment must = 4°4 X wind train, 
or double that required for the Tay Bridge. 
A nunierical value (possibly subject to modification) 
may be given thus:—Suppose the surface of a train to 
= 3000 square feet. With the Government scale of 56 lbs. 
for high wind, the lateral pressure =75 tons ; and, using 
leverage numbers as above, one Forth-attachment = 330 
tons. And this is the strain which each attachment must 
be able to sustain in respect of resistance to the effect of 
wind upon a train. I imagine that this has been pro- 
vided, at least in great measure ; but I think it desirable 
that attention should be called to the magnitude of the 
forces here concerned. 
The able and experienced engineer who has under- 
taken the prosecution of this great work, will, I am con- 
fident, recognise the possibility of serious inconvenience 
(yet unforeseen) arising from the points to which I have 
alluded in NATURE, vol. xxvi. p. 599—the novelty of 
plan, at least in this country —the magnitude of plan—the 
want of experience in a rising scale of magnitude. Should 
the bridge be erected successfully, I can imagine that 
many difficulties on small points might arise. For in- 
stance :—all matter yields to force; the brackets of fur- 
long-length, could not strictly preserve their form under 
the passage of a train; the connection of the end of one 
bracket with the beginning of the next is not very perfect, 
and I can hardly imagine that trains could be run through 
at speed (which, as I understood, is one of the conditions 
to be secured). 
I still prefer the principle of suspension. I would 
propose for further consideration the modifications which 
I have suggested in NATURE, vol. xxvi. p. 600, for 
giving enlarged width with diminished height to the top 
of the piers, and for use of wire in forming the suspen- 
sion-chains. G. B. AIRY 
The White House, Greenwich, December 4 
ment = X wind X train = 2719 X wind X train. If 
NOTES 
Monpay’s sitting of the Paris Academy of Sciences was one 
of unusual interest. M. Jamin, who was in the chair, delivered 
an eloquent address on the services rendered to science and to the 
Academy by M. Dumas, and presented to the illustrious Per. 
petual Secretary the medal subscribed for by his admirers as a 
testimonial on the occasion of the fiftieth year of his nomination 
as an academician, The medal is accompanied by silver and 
bronze replicas. 
numerous, broke into enthusiastic plaudits. 
The whole of the audience, which was very | 
When the enthu- 
siasm subsided, M. Dumas returned thanks, which he did with 
masterly eloquence, 
WE regret to announce the death of the Rey. James Challis, 
M.A., F.R.S., Plumian Professor of Astronomy and Fellow of 
Trinity College, which took place on Sunday morning at his 
residence in Cambridge, after a long illness. The late Professor 
was born in 1803, and educated at Trinity College, where he 
graduated B.A. in 1825 as {Senior Wrangler and first Smith’s 
prizeman. In 1836 he was elected Plumian Professor of Astro- 
nomy in succession to Mr. (now Sir) G. B. Airy, and also held 
the important post of Director of the Cambridge Observatory. 
The latter post he resigned in 1861, and was succeeded by Prof. 
Adams. He was at the time of his death the Senior of the 
Professors at Cambridge, and until about two years ago person- 
ally discharged the duties of his professorship, when increas- 
ing age and infirmities compelled him to appoint a deputy. 
Prof. Challis has published a considerable number of scientific 
works, including twelve volumes of astronomical observations. 
THE death is announced of Dr. Gustave Svanberg, formerly 
Professor of Astronomy and Director of the Observatory of 
Upsala University. He died on November 21, in his eighty- 
first year, 
News from Aden reports the death of Marchese Orazio 
Antinori, the well-known zoologist and African traveller, whe 
had recently started on a new expedition to the Upper Nile. 
He was seventy-one years of age, 
ELABORATE preparations were made in variows parts of 
America to observe the transit of Venus yesterday. The Western 
Union Telegraph, to facilitate observations, arranged to transmit 
Washington time wherever desired, in order to secure accuracy 
in recording results. Some enthusiastic astronomers had pro- 
posed general prayer in the churches on Sunday last for clear 
weather. 
M. W. DE FONVIELLE has published the first number of a 
new astronomical journal, called ‘‘Les Passages de Venus,” 
which explains the great astronomical event, and is being sold 
in the streets of Paris at 1 sou, with illustrations indicating 
the phase, and giving instructions for their observation in 
France. ‘The editor states that he trusts that the sec: nd number 
will appear at the right date, June 8, 2004, and the third in 
June, 2012, and so on, as long as there will be on the earth 
rational beings intelligent enough to take an interest in the 
transit of Venus. He congratulates himself on haying esta- 
blished a ‘‘ periodical”? which will be perhaps the most durable 
foundation of his age. 
A Swiss Geological Society has lately been formed. It is an 
offshoot from the Helvetic Society of Natural Sciences. While 
a permanent section of this, it will have its own life, its com- 
mittee, i's funds, its distinct séaz-es, and its publications if 
thought desirable. It will have members who do not belong to 
the mother society; will send a delegate to the preparatory 
assembly of the latter, and will have the right of presentation of 
members. The number of adhereits of the new scciety is 
already over sixty. It has absorbed the Congress der Feld 
Geologen and the Comité d’ Unification géologique. Among other 
things it will encourage excursions along with discussion on the 
ground, and will represent Switzerland in the International Geo- 
logical Congresses. The Society has testified its respect for 
MM. Studen, Heer, and Merian, by (exceptionally) giving them 
the title of Honorary Members. 
TuHeE Council of the British Association, acting under the 
powers conferred upon them by the General Committee, in 
accordance with their Report, have appointed the following to 
be a Committee, ‘‘to draw up suggestions upon methcds of more 
