Rodolfo Amedeo Lanciani.

The American journal of science and arts online

. (page 66 of 109)
Online LibraryRodolfo Amedeo LancianiThe American journal of science and arts → online text (page 66 of 109)
Font size
QR-code for this ebook


Digitized by VjOOQ IC



116 Scientific Intelligence.

contained ethyl benzoate, on being treated with potassium hydrate,
evaporating to dryness to remove the alcohol, re-solution in water,
and precipitation with hydrochloric acid, afforded benzoic acid
abundantly. The reaction, therefore, is as follows :

€gH5Br+€ej^j^2^«-fNa2=NaCl + NaBr + €eH5(€ee€,H,)
By using mono-bromo-toluol (^^^^ \ g ') toluic acid
(€JjH^ -J £i^L£i H ] with a trace of another acid perhaps



iso-



meric with it, was obtained. With the isomeric benzyl bromid
(CgHg(CH2Br)) the reaction yields a more complicated product.

In a more recent paper, Wurtz shows that the acid mentioned
above as obtained simultaneously with the toluic, is iso-toluic acid ;
and that its presence is due to the fact that the bromo-toluol Used,
contained an isomeric body. The substance obtained by acting
upon benzyl bromid or chlorid, he finds to have the composition
■Gj^Hj^Og, and he gives it the name di-benzyl-carboxync acid.
In a second operation, 262 grams benzyl chlorid, 108 grams ethyl
chlorocarbonate and 8,000 grams one per cent sodium-amalgam,
were heated on a saline bath, with an upward condenser, till the
whole mass was solid. This residue was extracted with ether,
the ether distilled off till the temperature rose to 180°, the fluid
remaining in the retort decomposed with alcoholic potash, the
the alcohol evaporated, the residue dissolved in water, precipitated
by hydrochloric acid and recrystallized from water. It separated
in drops which solidified to a mass of fine needles. It is almost
insoluble in cold water, and but little soluble in hot ; alcohol and
ether dissolve it readily. At 84° it melts and at a higher tempera-
ture distils. Its vapors are aromatic and irritating. To produce
it, Wurtz assumes that under the influence of the sodium, the
chlorid, by the loss of hydrochloric acid, becomes chloro-di-benzyl

V/ ft H K "V/Un

1^ and that this by the simultaneous action of the so-

dium and the ethyl chlorocarbonate becomes ethyl di-benzyl-carb-

oxylate ® *i ^ — Comptes Rendus^ Ixviii, 1298;

^ £JeH,€H€ee(€2HJ. ^ > > »

Ixx, 360. G. P. B.

1 6. On the volatile acids of Croton oil — ^Froelich having observed
in the Jena laboratory, that by the action of phosphorus penta-
chlorid upon ethyl-diacetic acid, two metameric chlor-acids were
obtained, yielding when treated with sodium-amalgam, two meta-
meric acids of the composition G^H^O^j ^^ which one was solid
and identical with that prepared from allyl cyanid, the other was
fluid, and supposed to be the same as that descril»ed by Schlippe
as occurring m Croton oil, and called Crotonic acid, Geutheb
undertook a confirmation of this supposition. Having prepared
the volatile acids from four pounds of Croton oil, he finds that no
volatile acid of the composition CJ^HgO^ exists in this oil, and
that the solid acid contamed in it is not angelic acid ; and tiiere-



Digitized by VjOOQ IC



Physics and Chemistry, 117

fore, that Schlippe's statements are entirely erroneous. The vola-
tile fluid acids are essentially acetic, butyric and valeric, mixed
perhaps with traces of oenanthic acid and higher members of the
oleic series. The solid acid supposed by Schlippe to be angelic
acid, is a metamer of it, to which Genther gives the name Tiglic
acid. It constitutes more than a third of the volatile acids of
Croton oil, and forms a barium salt readily soluble in water,
crystallizing in pearly plates, and having the composition
O^H^Ba'Oj-fSHgO. It has a remarkably close correspondence
in properties with the methyl-crotonic acid of Frankland and
Duppa. It is therefore obvious that the name " crotonic " given
to the acid ^^^^^2'> ^^ ^ misnomer, since croton oil contains no
acid of this composition. Geuther therefore proposes to call the
chlor-acid of Froelich, mentioned above, which fuses at 59*5° and
boils at 194*8**, monochlor-quartenic acid, and the acid derived
from it by the action of sodium-amalgam, which is fluid at 15°
and boils at 171*9°, quartenic acid. For the metamer of the chlor-
acid, melting at 94° and boiling between 206°-2 1 1° with partial
decomposition, he proposes the name mono-chlor-tetracrylic acid ;
and for its derivative 64Hg02, first prepared from allyl cyanid
and till now called crotonic acid, the name tetracrylic acid. Its
aldehyd called croton-aldehyd by Kekul6, would therefore be
tetracryl-aldehyd. — Zeitschr, Chem.^ 11, vi, 26, Dec. 1869. g. f. b.

17. On the jRhenish creosote from beech-wood tar, — Under the
direction of Baeyer and Graebe in Beriin, Mabasse has made an
investigation of beech-wood creosote, with results far more satisfac-
torv and conclusive than had been previously obtained. The ma-
tenal on which he worked came from the manufactory of Dietze &
Company in Mayence ; it was colorless, a little thick, heavier than
water, in which it was scarcely soluble, and dissolved completely
in potassium hydrate solution. On subjecting it to fractional dis-
tillation, three separate products were oDtained : one boiling below
199°, one between 200° and 203° (by far the larger portion) and
one between 216° and 220°. After drying the lightest product,
and subjecting it to sixteen fractional distillations, a body was
obtained, which, boiled between 183° and 184°, solidified on cool-
ing, and had the properties of phenol, which an analysis proved it
to be. On distilhng the second and largest fraction with zinc-dust
and puriiying and fractioning the distillate, two products were
obtained; the one, boiling between 110° and 112°, proved on anal-

ysis to be toluol,€?,Hg, or "Ge^4 *! H '* ^^°^® *^® zinc-dust acts

by reducing hydroxyl to hydrogen, the body yielding this toluol

must have been C^H^ ] rvrr^or cresoL The other portion boiling

at 160° to 156° afforded the properties and composition of anisoL

As this anisol "66^4 ] OPH ^^®® ^^* exist in the creosote as such,

it must have been produced by a similar action of the zinc-dust,

f ATT

from the body €eH^ •< ^qtt which is guaiacol, the acid methyl



Digitized by VjOOQ IC



118 Scientific Intelligence,

{ OH

ether of pyrocatechin €5^4 ] aw' '^^^ *^® fraction boiling be-
tween 200** and 203** was thus composed, Marasse fhrther proved
by fusing it with potassium hydrate. Two liquids were thus
obtained which on examination proved to be cresol itself

I x^ti ^ ( OH

€jH^-< OH^' ^^^ pyro-catechin C^H^ •< ^tt, the latter produced

by the saponification of its ether, guaiacol, in the experiment.
l!he same result was reached by acting upon this fraction with
hydriodic acid ; cresol and pyroKjatechin being produced as before.
And finally, by acting upon this fraction with methyl iodid and
potassium h\drate in sealed tubes, the methyl ethers of both cresol

t -Pfj \ ( 0"GH \

(cresyl-anisol C^H^ < OgIi ) *^<1 g^^"^*^^^ (^e^* 1 0€JH^)^^'^
obtained. The last fraction, boiling between 21Y** and 220°, af-
forded, after reduction with hydriodic acid and fractioning, phlorol,
( €H3 C €H3

- CHj and homo-pyro-catechin CJ^Hg J OH ,
(OH (OH

which last substance was derived from creosol, its acid methyl

ether OgHg i OCHj precisely as pyro-catechin was in the previous

( OH
fraction, from guaiacoL Marasse hence concludes that Rhenish
beech-wood creosote is a mixture of compounds belonging to two
parallel series, the phenols and the acid methyl ethers of pyro-cate-
chin and its homologues. And since the first members of the
series do not coincide in boiling point, the first member of the
guaiacol series agreeing with the second member of the phenol
series, it is obvious that that portion of creosote which boils at the
lowest temperature will consist of the first member of the phenol
series, L e., phenol itself

Phenol Bofling OoAteool Bomng

Series. point Serte*. point.

Phenol, CeH^(OH)^ 184° C,



d^H.^OorCeHg



sH,(OH)
Cresol, €^^4 ] ^^^ 203°

r€H,
Phlorol, e^U^ \ €H3 220°
(OH



Guaiacol, ^eH*'] e€H ^^^"^ ^•

Creosol, ^jH, ) OCfe, 219°
(OH



All the different kinds of beech-wood creosote appear to be identi-
cal in composition; those specimens having the highest boiling
point, which contain the higher members of these parallel series. —
Ann. Ch. Pharm., clii, 69, Oct., 1869. g. f. b.

16. On Ocean Ourrents^ in relation to the Distribution of Heat
over the Glohe^ by Jambs Croll of the Geological Survey of Scot-
land. (PhiL Mag., Feb. 1870.) — \. The abeolvJte Heating-power of
Ocean-currents, — * * * From an examination of the published sec-
tions [of the Gulf Stream] some years ago,* I came to the conclu-

* PhiloBophioal Magazine for Februaiy, 1867, p. 127.



Digitized by VjOOQ IC



Physics cmd Chemistry. 119

sion that the total quantity of water conveyed by the stream is prob-
ably equal to that of a stream 50 miles broad and 1000 feet deep,*
flowing at the rate of four miles an hour, and that tbe mean tempe-
rature of the entire mass of moving water is not under 65^ at the
moment of leaving the Gul£ I thimc we are warranted to conclude
that the stream, b^ore it returns from its northern journey, is on
an average cooled down to at least 40°; consequently it loses 25° of
heat. Each cubic foot of Water, therefore, in this case canies from
the tropics for distribution upwards of 1500 units of heat, or
1,158,000 foot-pounds. According to the above estimate of the
size and velocity of the stream, 5,575,680,000,000 cubic feet of
water are conveyed from the Gulf per hour, or 133,816,320,000,000
cubic feet daily. Consequently the total quantity of heat trans-
ferred from the equatorial regions per day by the stream amounts
to 154,959,300,000,000,000,000 footrpounds.

From observations inade by Sir John Herschel and by M. Pouil-
let on the direct heat of the sun, it is found that, were no heat
absorbed by the atmosphere, about 83 foot-pounds per second
would fall upon a square foot of surface placed at right angles to
the sun's rays.f Mr. Meech estimates that the quantitv of heat
cut off by the atmosphere is equal to about 22 per cent of the total
amount received from the sun. M. Pouillet estimates the loss at
24 per cent Taking the former estimate, 64*74 foot-pounds per
second will therefore be the quantity of heat falling on a square
foot of the earth's surface when the sun is in the zenith. And
were the sun to remain stationary in the zenith for twelve hours,
2,796,763 foot-pounds would fall upon the surface.

It can be shown that the total amount of heat received upon a
unit surface on the equator during the twelve hours from sunrise
till sunset at the time of the equinoxes is to the total amount which
would be received upon that surface, were the sun to remain in
the zenith during those twelve hours, as the diameter of a circle to
half its circumference, or as 1 to 1*5708. It follows, therefore,
that a square foot of surface on the equator receives from the sun
at the time of the equinoxes 1,780,474 foot-pounds daily, and a
square mile 49,636,750,000,000, foot-pounds daily. But this
amounts to only Tra+my P^^ ^^ ^^® quantity of heat daily con-
veyed from the tropics by the Gulf-stream. In other words, the
Gulf-stream conveys as much heat as is received from the sun by
3,121,870 square miles at the equator. The amount thus conveyed
is equal to all the heat which falls upon the globe within 63 miles
on each side of the equator. According to calculations made by
Mr. Meech,;^ the annual quantity of heat received by a unit surface
on the frigid zone, taking the mean of the whole zone, is ^^ of

♦ The Gulf-stream at the narrowest place examined by the Coast Survey, and
the place where itn velocity was greatest, was found to be over 30 statute miles
broad and 1950 feet deep. But we must not suppose this represents all the warm
water which is received by the Atlantic from the equator; a great mass of water
flows into the Atlantic without passing through the Straits of Florida.

J Trans, of Roy. Soa of Edinb., vol xii, p. 57. Phil. Mag., S. 4, voL ix, p. 36.
Smithsonian Contributions to Knowledge, vol. ix.



Digitized by VjOOQ IC



120 Scientific Intelligence,

that received at the equator ; consequently the quantity of heat
conveyed by the Gulf-stream in one year is equal to the heat which
falls on an average on 6,873,800 square miles of the arctic regions.
The frigid zone or arctic regions contain 8,130,000 square miles.
There is actually, therefore, nearly as much heat transferred from
tropical regions by the Gulf-stream as is received from the sun by
the entire arctic regions, the quantity conveved by the stream to
that received from the sun by those regions being as 15 to 18.

But we have been assuming in our calculations that the percent-
age of heat absorbed by the atmosphere is no greater in polar
regions tjban it is at the equator, which is not the case. If we
make due allowance for the extra amount absorbed in polar regions
in consequence of the obliqueness of the sun's rays, the total quan-
tity of heat conveyed by the Gulf-stream will probably nearly
equal the amount received from the sun by the entire arctic
regions.

If we compare the quantity of heat conveyed by the Gulf-stream
with that conveyed by means of atrial currents, the result is equally
startling. The density of air to that of water is as 1 to 770, and
its specific heat to that of water is as 1 to 4*2 ; consequently the
same amount of heat that would raise 1 cubic foot of water 1®
would raise 770 cubic feet of air 4**-2, or 3234 cubic feet 1°. The
quantity of heat conveyed by the Gulf-stream is therefore equal
to that which would be conveyed by a current of air 3234 times
the volume of the Gulf-stream, at the same temperature and mov-
ing with the same velocity. Taking, as before, the width of the
stream at 50 miles, and its depth at 1000 feet, and its velocity at
4 miles an hour, it follows that, in order to convey an equal amount
of heat from the tropics by means of an atrial current, it would
be necessary to have a current about 1 ^ mile deep, and at the tem-
perature of 65°, blowing at the rate of four mues an hour from
every part of the equator over the northern hemisphere towards
the pole. If its velocity were equal to that of a good sailing-
breeze, which Sir John Herschel states to be about twenty-one
miles an hour, the current would require to be above 1200 feet
deep. A greater quantity of heat is probably conveyed by the
Gulf-stream alone from tne tropical to the temperate and arctic
regions than by all the atrial currents which flow from the equator.

« * « « 4c

The anti-trades or upper return-currents, as we have seen, bring
no heat from the tropical regions. After traversing some 2000
miles in a region of extreme cold they descend on the Atlantic as
a cold current, and there absorb the heat and moisture which thej
carry to northeastern Europe. Those atrial currents derive their
heat from the Gulf-stream, or if it is preferred, from the warm
water poured into the Atlantic by the Gulf-stream. How, then,
are these winds heated by the warm water ? The air is heated in
two ways, viz : by direct radicUion from the water, and by c<mt€tc$
with the water. Now, if the Gulf-stream continued a narrow and
deep current during its entire course similar to what it is at the
Straits of Florida, it could have little or no opportunity of com-



Digitized by VjOOQ IC



Physics and Chemistry,' 121

manicating its heat to the air either by radiation or by contact.
If the stream was only about 40 or 50 miles in breadth, the atrial
particles in their passage across it would not be in contact with
warm water more than an hour or two. Also the number of the
particles in contact with the water, owing to the narrowness of
the stream, would be small, and there would therefore be little
opportunity for the air becoming heated by contact. The same
also holds true in regard to radiation. The more we widen the
stream and increase its area, the more we increase its radiating
surface ; and the greater the radiating surface, the greater is the
quantity of heat thrown off. But this is not all ; the number of
atrial particles heated by radiation increases in proportion to the
area of the radiating surface ; consequently the wider the area over
which the waters of the Gulf-stream are spread, the more effectual
will the stream be as a heating-agent. And, again, in order that
a very wide area of the Atlantic may be covered with the warm
waters of the stream, slowness of motion is essential * * *

The quantity of heat conveyed by the Gulf-stream, as we have
seen, is equal to all the heat received from the sun by 3,121,870
square miles at the equator. Mr. Findlay, however, as has been
stated, thinks that I have doubled the actual volume of the stream.
Assuming that I have done so, the amount of heat carried by the
stream would still be equal to all the heat received from the sun
by 1,560,935 square miles at the equator. The mean annual quan-
tity of heat received from the sun by the temperate regions per
umt surface is to that received by the equator as 9-83 to 12.* Con-
sequently the quantity of heat conveyed by the stream, taking
Mr. Findlay*8 estimate of its volume, is equal to all the heat
received from the sun by 2,062,960 square nules of the temperate
regions. The total area of the Atlantic from the latitude of the
Straits of Florida, 200 miles north of the tropic of Cancer, up to
the Arctic Circle, including also the German Ocean, is about
8,500,000 square miles. In this case the quantity of heat carried
by the Gulf-stream into the Atlantic through the Straits of Florida,
to that received by this entire area from the sun, is as 1 to 4*12,
or in round numbers as 1 to 4. It therefore follows that one-fifth
of all the heat possessed by the waters of the Atlantic over that
area, even supposing that they absbrb every ray that falls upon
them, is derived from the Gulf stream. Would those who call in
question the efficiency of the Gulf-stream be willing to admit that
a decrease of one-fourth in the total amount of heat received from
the sun, over the entire area of the Atlantic from within 200 miles
of the tropical zone up to the arctic region, would not sensibly
affect the climate of N orthem Europe ? If they would not wiU-
ingly admit this, why, then, contend that the Gulf-stream does not
attect climate ? for the stoppage of the Gulf-stream, taking it at
Mr. Findlay's estimate, would deprive the Atlantic of 77,479,650,
000,000,000,000 foot-pounds of energy in the form of heat per day,
a quantity equal to one-fourth of j3i the heat received from the
sun by that area.

* See Smithsonian Contributions to Knowledge, vol ix.



Digitized by VjOOQ IC



122 Scientific Intdltgenoe.

Were the sun extinguished, the temperature oyer the whole
earth would sink to nearly that of stellar space, which, according
to the investigations of Sir John Herschel* and of M. Pouillet,t is
not above — 239° F. Were the earth possessed of no atmosphere,
the temperature of its surface would sink to exactly that of space,
or to that indicated by a thermometer exposed to no other heatr
influence than that of radiation from the stars. But the presence
of the atmospheric envelope would slightly modify the conditions
of things ; for the heat from the stars (which of course constitutes
what is called the temperature of space) would, like the sun's heat,
pass more freely through the atmosphere than the heat radiated
back from the earth, and there would in consequence of this be an
accumulation of heat on the earth's surface. The temperature
would therefore stand a little higher than that of space ; or, in
other words, it would stand a little higher than it would otherwise
do were the earth exposed in space to the direct radiation of the
stars without the atmospheric envelope. But, for reasons which
will presently be stated, we may in the mean time, till ftirther light
is oast upon this matter, take — 239° F. as probably not far from
what would be the temperature of the earth's surface were the
sun extinguished.

Suppose, now, that we take the mean annual temperature of the
Atlantic at, say, 66^I Then 230**+66°=296° represents the num-
ber of degrees of rise due to the heat which it receives. In other
words, it takes all the heat that the Atlantic receives to maintain its
temperature 296° above the temperature of space. Stop the Gulf-
stream, and the Atlantic would be deprived of one-fifth of the heat
which it possesses. Then, if it takes five parts of heat to main-
tain a temperature of 296® above that of space, the four parts
which would remain after the stream was stopped would only be
able to maintain a temperature of four-fifths of 296° or 236** above
that of space : the stoppage of the Gulf-stream would therefore de-
prive the Atlantic of an amount of heat which would be sufficient
to maintain its temperature 69<> above what it would otherwise
be, did it depend alone upon the heat received dii*ectly from the
sun. It does not, of course, follow that the Gulf-stream actually
maintains the temperature 69** above what it would otherwise he
were there no ocean-currents, because the actual heating-effect of
the stream is neutralized to a very considerable extent by cold
currents from the arctic regions. But 69** of rise represent its
actual power; consequently 69**, minus the lowering enect of the
cold currents, repres^it the actual rise. What the rise may
amount to at any particular place must be determined by other
means. * ♦ ♦

♦ 'Meteorology,' Section 36.

f Comptes Rendns, July 9, 1838. Taylor's Sdentiflc MenKnrs, vol ix, p. 44,
(1846).

X The mean temperature of the Atlantic between the tropics and the arctic
circle, acoordmg to Admiral FitsBoy's chart, is about 60^. But he assigns far too
high a temperature for latitudes above 50^. It is probable that 60^ is not far from
the troth.



Digitized by VjOOQ IC



Physics (md Chemistry, 128

At present there is a difference merely of 80° between the mean
temperature of the equator and the poles ;* but were each part of
the globe's surface to depend alone upon the direct heat which it
receives from the sun, there ought, according to theory, to be a
difference of more than 200^. The annual quantity of heat received
at the equator to that received at the poles, supposing the propor-
tionate quantity absorbed by the atmosphere to be the same in
both cases, is as 12 to 4*98, or, say, as 12 to 5. Consequently if
the temperatures of the equator and the poles be taken as propor-
tionate to the absolute amount of heat received from the sun, then
the temperature of the equator above that of space must be to
that of uie poles above that of space as 12 to 5. What ought,
therefore, to be the temperatures of the equator and the poles, did
each place depend solely upon the heat which it receives directly
from the sun ? Were all ocean and aerial currents stopped, so that
there could be no transference of heat from one part of the earth's
surface to the other, what ought to be the temperatures of the
equator and the poles ? We can at least arrive at a rough esti-
mate on this point. If we diminish the quantity of warm water
conveyed from the equatorial regions to the temperate and arctic
regions, the temperature of the equator will begm to rise and the
temperature of the poles to sink. It is probable, however, that
this process would anect the temperature of the poles more than
it would do that of the equator; lor as the warm water flows from
the equator to the poles, the area over which it is spread becomes
less and less. But as the Ivater from the tropics has to raise the
temperature of the temperate regions as well as the polar, the dif-
ference of effect at the equator and poles might not, on that
account, be so very great. Let us take a rough estimate. Say
that, as the temperature of the equator rises one degree, the tem-
perature of the poles sinks about one degree and a hal£ The
mean annual temperature of the globe is about 68°. The mean
ten^rature of the equator is 80°, and that of the poles 0°. Let
ocean and atrial currents now begin to cease, the temperature of
the equator begins to rise and the temperature of the poles to sink.
For every degree that the equator rises the poles sink \\°\ and
when the currents are all stopped and each place dependent alone
upon the direct rays of the sun, the mean annual temperature of
the equator above that of space will be to that of the poles,
above that of space, as 12 to 5. When this proportion is reached,



Online LibraryRodolfo Amedeo LancianiThe American journal of science and arts → online text (page 66 of 109)