The daily exchange. [volume] (Baltimore, Md.) 1858-1861, 1858-05-03

Mr.. A. b. Engstrom afterwards gave some very
interesting experiments on the "Etfect of Sound
that is produced in different Stages of the Atmos-
phere." During his remarks he stated that he had
one occasion taken small bell, and went out in
a boat half mile from the shore, and submerged the
bell to the depth of about inches. Upon its being
struck, persons on the shore distinctly heard the
sound.
Prof. Bache stated that he had made experiments,
which resulted entirely adverse to those of Mr.. Eng
strom.
The Dynamics Of Ocean Currents were read by +.
B. Hunt Esq. This subject very interesting
one but will not admit of our giving it in detail.
owing to its complicated nature. 1t was received
with applause.
The next paper was, con the Calculation of the
Earthwork Of Railroads, &c" by Prof. W. NJ. Gil
leSpie of Union College, New York The Professor
illustrated his paper by diagrams and models discus
sing the usual method of calculating the contents of
the excavations and entertainments of railroads. &C.,
on sidelong and irregular ground. At the Montreal
meeting he had shown that the contents of such
ground, bounded in part by warped surfaces could be
calculated with perfect precision by the familiar pris
modal formula, and he now proposed to test by this
the methods IN common use. and to establish rules by
which the nature and extent of their errors could be
determined in advance. The investigation was con-
Quoted by mathematical symbols. which we cannot
reproduce and give only the practical deductions
LIST. The method of ''averaging end areas COM
monty in use by engineers, though supposed ALWAYS
to give too great result, found to give too 1t
tie III just as many cases; the result being as OBJ
tanned by transating the resulting formula into
common language that this method gives too little,
whenever the of the products of the depths Tor
height of the mass in question situated diagonally
opposite to each Othr is greater than the of
the products of those belonging to the same cross
section.
ID The method of middle areas gives results too
small when the preceding method gives too large
ones, and vice versa the absolute error, however,
being only half so great.
Sd. The method Of ''Equivalent mean heights
shown ~
rays gives too small result, with one exception.
viz: when the products of the parts Of heights
diagOnally opposite to each other are equal. But
this method is the one now always resorted
to when perfect accuracy is desired and most tables
and diagrams for sideong ground based upon
it. Since, however, it is always wrong, and its
errors do not even balance each other in the long
run, but it always errs on the same side. and this
tece it urged that its employment should be at
once abandoned, since it the most dangerous
kind of foe, being ga wolf in sleeps clothing.
In a numerical example given, average end areas
"gaye 600 cubic feet too little middle areas gave
800 to much, and this last method gave $50 too lit
tie, which was nearly 3 per cent. of the whole
amount, very important difference on work which
on many railroads is counted by millions of wards.
The paper listened to with much interest, not
only by the scientific gentlemen present. but by the
large audience in attendance
Prof. Bache next read paper ''On the results of
DR.. kane's Magnetic Observations in his Artic Ex-
petition
1t proved highly interesting detail, but was
such paper that any synopsis could but do it in
justice, and we cannot only regret lack Of space
to give it entire. 1t was received with much favor,
and with remarks of an approbatory character by
Prof. Henry.
The next paper read was a ''Notice of New
Bases, containing Metals and the Elements of Am
monia, by Walcott Gibbs" paper evidencing that
its author well skilled in chemical analysis
a paper styled ''The Phylotaxis deduccd from the
Mathematical Definition of Distribution, was next
read by Chauncy Wright. and illustrated upon the
blackboard, by which alone could its contents be
detailed.
Henry Wurtz then read paper :" On the Action
of Nitric Acid on the Metallic Chlordes with a new
method for the separation of magnesia from the al
kalies, and new modes of obtaining pure compounds
OF EdFi",a, Nromium and Cadmium. detailing the
results of various chemical experiments"
The Section then adjourned.
SECTION B.
Prof. Swallow called section 3. to ORDER after
which DR.. r. w. Gibbs, of S. c., was elected Chair
man for the day.
\ communication was received from Lieutenant
Warren, of the Typographical engineers. with a
map OF the country lying between the MisssSip-
pi river and the Pacific ocean. which was accepted.
Prot. Swallow read paper On the Rocks of Kan
sas." lie presented chart of the Territory, and
showed the work to consist of several varieties all
lying between coal and chalk. The lower carbon
ferrous occupies a small part Of the northwestern
section of the Territory. From the researches of
DR.. Horn he was satisfied that there We're beds of
each throughout the whole area. There were some
doubtful beds, composed of several varieties There
were some so specimens OF fossils taken from the
permanent rocks Among the fossils there were
found ID European species. The central portion of
Kansas is SANDY, so as to be almost desert waste
but there is a plentiful supply of gypsum, with
which to make it fertile.
After the reading of the paper, some conversation
took place between Prof Weeks and Dr. Hall, the
former of whom complained that he was entitled to
credit discovery q
The president declared the conversation out of
order, and asked the gentlemen to coniine their re
marks to the subject which had the attention Of the
association.
Mr.. Weeks then gave notice that he would pre-
sent written statement on Monday, showing his
connections with the discovery of penncan rocks in
America.
Prof. Rogers considered this a most important
subject, and one which should command the closest
attention. He did not think the discovery of
grut would carry conviction to the minds of gcOlo~
gsts abroad sufficient to convince them of the OK
istcnce of pure pennean vein in this country
1t should be thoroughly examined, and all the proofs
obtained.
Prof. Swallow replied that he knew nothing about
the rocks other than what he had heard from Mai.
Hone. and the specimens of fossils which he had OBJ
tanned.
\. II. Worthcn read paper on the pennean
rocks OF Illinois, He presented a number OF fossil
specimens which had been taken from under thin
band of iron in Gallatin county, on the border
of the Sabine river.
DR.. Hall made statement relative to the pen
mean series discovered in the western portion
Of the country, having had considerable expert
ence in the examination of the fossils of that land.
Prof Henry Rogers objected to the nomcncla-
ture for American fossils, for which there was a
want of conformity in the deposits at Penna, Rus
STA. There was no evidence of any break in Kan
sas, therefore the law should go from America, and
not from Russia.
The next paper read was by Henry Wurtz on the
occurrence of cobalt and nickel in CASTOR county,
North Carolina.
W. D. Whitney read paper "On the Analysis.
Classification and Representation of the Sounds of
language, and in the mode of pronunciation gave
examples which are precisely the same as used in
Southern Germany.
There were several other papers in he program
for the day, but the hour for adjournment having
arrived they were postponed.
EXCURSION TO FORT McIIENRY.
At O'Clock in the afternoon the members of the
Association, number of the delegates to the SAM
tary Convention, the Mayor and City Council, and
several of the city officials, with large number of
our citizens, of both sexes embarked on board the
steamer PocahOntas, for an excursion down the
river-the entire body Of guests being equal, in
point of numbers, to the capacity of this spacious
steamer. Arriving ut this memorable spot, the
company was met and welcomed by the command
ant Major French, and his suite of officers and
conducted to the parade ground whore concourse
OF our citizens estimated at two thousand persons
awaited their arrival, attracted there by the antici-
pated unusual military display of the artillery