John Almon.

The American journal of science and arts online

. (page 45 of 102)
Online LibraryJohn AlmonThe American journal of science and arts → online text (page 45 of 102)
Font size
QR-code for this ebook

manner as to increase its existing polarity. The force required to turn
the armature then becomes vastly increased, as well as the intensity of
induced current In this case also the residual magnetism of the iron is
the primary cause of the current which then goes on increasing up to a
maximum, at the expense of course of a certain amount of work ex-
pended in producing rotation. When a cross wire is placed so as to
^divert a portion of the current from the electro-magnet a remarkable in-
<$rease in the heating and magnetizing power of the current is observed.
Wheatstone accounts for this increase by supposing that the current
passing through the armature branch and cross wire experiences a much
less resistance than if it had passed through the armature and electro-
magnet branches, and though the electro-motive force is less, the resist-
ance having been rendered less in a greater ratio, the resultant effect is
greater. In conclusion Wheatstone points out the analogy between the
augmentation of the power of a weak magnet by means of an inductive
action produced by itself, and the accumulation of power shown in the
electrical machines of Holtz and others, in which a very small quantity
of electricity is made by a series of inductive actions to equal or exceed
the effects of the most powerful machines of the ordinary construction.
— Proc. of the Royal Society, xv, 367, 369. w. o.

2. New applications of methods of reduction in organic chemistry, —
Bkrthelot has studied the action of iodhydric acid upon a variety of
organic compounds, and has greatly extended our knowledge of the
transformations produced by this valuable reagent the introduction of
which, it will be remembered, is due to himself. The experiments were
conducted by introducing the organic matter to be operated on into a
tube with a very concentrated solution of iodhydric acid, sealing the tube
and heating to a temperature of 275^ C. In this manner the iodid, bro-
mid, and cblorid of ethylene yield hydruret of ethylene, haloid acid, and
free iodine, the reaction in the case of the iodid being represented by
the equation


Digitized by


Chemisiiy and Physics. 387

and in the case of the bromid of ethylene by the equation

In like manner di-iodhydrate of acetylene, C^H2(2HI), and iodid of
ethyl, G^H^I, yield hydruret of ethylene and free iodine. Iodid of allyl
yields hydruret of propylene, according to the equation

lodhydrio acid acts even upon perch lorinated compounds ; thus sesqui-
chlorid of carbon, O^Clg, reacts with it according to the equation

C4Cle+12HIz=C4He + 6HCI+6I2.
All the hydrocarbons capable of uniting directly with iodhydric acid, as
for instance all the ethylenes and acetenes, O^nHjn Ai^d C2nB^2n-2^ ^^^
unite with iodhydric acid, and afterward by the action of an excess of
the acid upon the new compound formed, yield a new hydrocarbon and
free iodine.

Alcohols treated in the same manner yield first the iodids of the radi-
cals and these then react with iodhydric acid in the manner explained
above. Thus the first action of iodhydric acid upon common alcohol
may be represented by the equation

C^He02H-4HI=C4He +H2O2 + 2I2,
iodid of ethyl being an intermediate product. In like manner glycerine
yields hydruret of propylene.

Ethers derived from the oxacids are first decomposed with fomtation
of an iodid of the radical and regeneration of the oxacid ; the iodid and
oiflacid are then separately acted on by the excess of free iodhydric aeid.
Thus methyl-formic ether and iodhydric acid react according to the


Common aldehyd yields hydruret of ethylene mixed with hydrogen
and probably with some marsh-gas. Acetone gives hydruret of propy-
lene according to the equation


but the hydruret of propylene undergoes a partial decomposition, proba-
bly according to the equation

Organic acids treated with iodhydric acid are reduced to formenes
containing the same quantity of carbon as the acid, provided that these
are sufficiently stable to resist a temperature of 275^ C. Thus acetic
add reacts according to the equation

Succinic acid, like butyric acid, yields hydruret of butylene ;
The author remarks that the facts mentioned above furnish a general
method of reproducing the fundamental hydrocarbon of each series by
means of all the bodies in the series. Thus hydruret of ethylene,
CLH^CHa), yields by replacement GJi4,{C\2), C^R^mi), C^H^
(HaOj), 0^2^4(04), and C4H2(04)(04), in each the substitution being

Digitized by


388 'Scientific InUlligence,

by equal volumes. All these compounds, by the reducing action of iod-
hydric acid, reproduce the original hydrocarbon, C^H^. — Bull, de la
Sociiti Chimique, Janvier, 1867, p. 53. w. o.

3. On the monatomtc nitriles, — ^The monatomic nitriles may be re-
garded as primary monamines, the three atoms of hydrogen in ammonia
being replaced by one atom of a triatomic radical. L. Henry has shown
that this view is supported by several new and interesting facts. Thus
acetonitrile, (€2^3)'"^, readily unites with dry bromhydric and iodhy-
dric acids with production of intense heat. The resulting salts are solid
crystalline white bodies, soluble in alcohol but insoluble m ether. They
are rapidly decomposed by water or moist air, forming acetic acid and
salts of ammonia. Benzonitrile gives analogous compounds. Sulpho-
cyanic acid and sulphocyanid of ethyl may also be referred to the type
of ammonia, like the corresponding cyanic acid and cyanid of ethyl.
The sulphocyanida of ethyl and allyl combine readily with dry bromhy-
dric and iodhydric acids, giving white crystalline bodies decomposed by
water. — Bull, de la Soc, Chim., Janvier, 1867, p. 86. w. o.

4. On graphitoid boron. — Wohler has obtained the so-called graphi-
toid boron, discovered by Deville and himself, in sufficient quantity for
analysis, and has found that the substance in question is not boron but a
compound of boron and aluminum. The compound is always formed
in preparing crystallized boron or by fusing aluminum in the vapor of
chlorid of boron. The borid crystallizes in very thin pale copper-colored
six-sided tables which, according to Prof. W. H. Miller, are monoclinic.
It does not burn in the air but burns in chlorine with brilliancy, forming
chlorid of aluminum and chlorid of boron. Two analyses led to the
formula AIB^^. — Ann. der Chemie und Pharm., cxii, 268. w. o.

6. On the constitution of mellitic acid. — Bister and Soheibler have
found that mellitic acid is six-basic and has the constitution of benzol,
in which six atoms of hydrogen are replaced by six of carbonyl, CO^Hf
so that its formula is €)e(€02^)6' When heated with lime it is com-
pletely decomposed into carbonic acid and benzol. With sodium amal-
gam mellitic acid takes up six atoms of hydrogen and forms the six-basic
acid, €gHg(€J02H)6» which, when heated with sulphuric acid, yields a
four-basic acid, €gH2(€02H)4. This can take up four atoms of hydro-
gen to form a new acid, which, when treated with sulphuric acid, again
loses carbonic acid. The final product of these transformations is ben-
SBoic acid. The authors beg chemists who may possess a stock of mellite
to supply them with material for their investigation. — Ann. der Chemie
und Pharm.^ cxli, 271. * w. o.

6. On the cyanic ethers. — Gal has studied the action of chlorhydric and
bromhydric acids upon cyanic ether. The dry ether absorbs chlorhydric
acid gas, and by distillation a liquid is obtained which has a penetrating
smell, fumes slightly in the air, and boils between 108^ and 112^ C.
The author gives to this body the formula C^H^O.C^NO.HCl, which
may be referred to the type of chlorid of ammonium, and written

Water decomposes thU substance, fonning chlorid of

Digitized by


Chemistry and Physics. 389

etbylammoDiam and oarbonic acid, the reaetion being expressed by the

Bromhjdric acid yields a similar compound boiling at 118*^-122^ C.
Heated in sealed tubes at 100"^ both compounds yield cyanuric ether and
free hydracid. The cyanic ether obtained by Cloez by*acting upon
ethylate of sodium with chlorid of cyanogen, and which is a neutral
liquid insoluble in water and not volatile, exhibits an entirely different
behavior toward the hydracids. Chlorhydric acid converts it into cy-
anuric acid and chlorid of ethyl, the reaction being represented by the

Bromhydric acid acts in a similar manner. Gal is of opinion that the

C H )
compound of Cloez is the true cyanate of ethyl, n^jj'' [ ^2> ^^^^^ ^®


cyanic ether of Wurtz is an ammonia, N •< ri^u^- The author promises

a further investigation of the subject The connection of his results with
those of L. Henry, mentioned above, will be obvious at a glance. — Bull.
de la Soe. Chim,, Dec 1866, p. 436. w. a.

Y. On the action of alcohols upon terchlorid of phosphorus, — When
absolute alcohol is poured drop by drop into an equivalent quantity of
terchlorid of phosphorus a powerful reaction ensues, the principal pro-
duct of which is a body having the formula P(C2H^O)Cl2, or oxethyl-
chlorid of phosphorus. This is a liquid boiling at 117^ C, heavier than
water, and decomposed by this into alcohol and phosphorous acid. Bu-
tjlic and amy lie alcohols give analogous bodies. — Bull, de la Soc. Chim,j
Dec 1866, p. 481. w. o.

8. On the polymers of acetylene. — Berthslot has studied the products
of the action of heat upon acetylene, and has arrived at results of great
interest and importance. When acetylene is heated to a temperature
approaching that at which glass melts, it is gradually converted into a
series of polymeric bodies, among which are benzol, styrol, reten, and
fluorescing hydrocarbons. In one experiment Berthelot prepared pure
acetylene by the direct combination of pure hydrogen and pure carbon,
and then obtained from this acetylene benzol, which was thus formed by
actual synthesis from its elements. The relation between the two sub-
stances is readily seen since 3C4H2=Cj2Hg; benzol is therefore tri-
acetylene. Berthelot believes that a volatile hydrocarbon occurring
among the products of the action of heat upon acetylene is diacetylene,
2C^U^=:G^B.^. Styrol or tetraoetylene, 4C4H2=CieHg, forming
about one-fifth of the entire product was easily recognized. Naphthalin
forms another product, and probably is a product of the decomposition
of pentacetylene, C^oHgrrSC^Hj— H^. The highest product yet ex-
amined is retene, which Berthelot regards as enneacetylene, C,oHj3=
OC^Hp. — Ann. der Chem. und Pharm., cxli, 173. w. o.

9. Jyew method for the preparation of oxygen, — ^When cuprous chlorid
Ou^Clg is exposed to the air, it absorbs oxygen and is converted into cu-
prous oxy-dichlorid Cu^OCl^. If this latter compound be heated to

Ax. JouB. Sol— Sbooxd Sbbies, Vol. ZLIII, Na 129.~Mat, 1867.

Digitized by


390 Scientific Intelligence.

about 400** C, it is decomposed into oxygen and cuprous chlorid, as

Upon this reaction Mallet founds a method for tbe commercial prepa-
ration of oxygen. Tbe cuprous salt, mixed witb sand or clay to prevent
fusion, is placed in a retort, wbicb can be rotated horizontally. It ia
readily oxydized by a current of air, passed over it for three or four
hours. The heat necessary for the decomposition is no higher than that
required for the preparation of oxygen from potassic chlorate. With this
arrangement the loss of material is inappreciable. Each kilogram of
cuprous chlorid yields 28 to 30 liters of oxygen.

A very simple modification of this method permits the preparation of
chlorine gas with equal facility. If after oxydation chlorhydric acid gas
be conducted over the cuprous oxy-dichlorid, the latter becomes cupric
chlorid, OuCl, . At a red heat, this salt decomposes into cuprous chlorid
and ehlonne.—L'Iwttitut^ 1867, p. 61.

10. Apparatus for detecting differences of density in transparent media,
— Dr. A. T5PLBR has given a new method of observing certain import-
ant phenomena which escape attention by direct vision more or less com-
Eletely. His pamphlet, "Beobachtungen nach einer neuen optischen
[ethode, Bonn, 1864," is not at hand ; but from a very complete synopsis
(with quarto plate) in Erganzungsblatter ziir Kenntniss der Gegenwart,
Hildburghausen, 1866, i, 88, and from his article on the application of
this method to microscopic observations, in Pogg. Ann., 1866, cxxvii,
556-580, we give the following :

liCt A be a radiant; a good lamp surrounded s

with a brass cylinder. The latter has a circular ▲ lm bt

opening, in front of which is placed a small ver- /

tical metallic screen with holes near its edge for

the transmission of the light from A. This pencil of light falls upon a
system of lenses, L, of at least two and a half to four feet focal length
and of large diameter. The lenses, L, in the usual tube, together witb
the lamp. A, and screen, are supported on the same table ; the screen
can be moved in the axis of the lens, L, to change the divergence of the
pencil. At a distance of from ten to twenty -five feet, L will give the
image B of A. Here a small astronomical telescope, T, is so placed in
the common axis that this image falls just on the front face of the objec-
tive ; at this point is placed a metallic screen, », having a straight, sharp
edge ; this screen can be moved by a screw, like the movable part in the
slide of Bunsen's spectroscope. This is the *' Schlieren ''-apparatus, which
hence may be put together in almost any philosophical cabinet

If the lens, L, is perfect, the entire beam of light is concentrated in
B ; and in moving the screen, «, down, no change in the image, B, is
observed until the screen reaches B, when the lens, L, suddenly disap-
pears. But if L is not perfect, if it contains a flaw,/ (i.e., Sckliere)^
then this will refract light differently from the body of the lens ; the rays
from / will not collect in B ; when s has nearly reached B, many of the
rays from/ (which otherwise would have reached the objective of T and
thus the eye) are now cut off; henQQ f appears dark on the bright ground
of the image of L. And when s is moved down so as completely to cut
off the regular image B, many of the rays from/ will yet reach the ob-

Digitized by


Chemistry and Physics. 391

jective, so that / noto appears bright upon a dark ground. As the dis*
taoce LT is quite considerable (even twenty feet or more), and as the
telescope may have considerable power, this method is incredibly sensi-
tive. The object to be examined must of course be transparent; if it is
the objective of a telescope, this serves as L; if a flame or the like, it is
placed at M near L, between L and T.

Topler has found that perfectly homogeneous glass is exceedingly rare ;
it has usually either filiform flaws (which are easily detected and but
little injurious) or has flaws throughout its entire mass, appearing in this
apparatus as if brushed over by a brush. These very injurious flaws
hitherto were not discovered till the lens was almost worked out ; by
this apparatus they are easily detected in the glass.

The Jlame of a Bunsen burner (placed at M) shows besides the three
well known parts visible to the unaided eye, two others : an exterior,
large, very well defined cone (consisting of the heated products of com-
bustion and of air) and a bright interior cone, resting on the tube as the
base, having a sharp outline (consisting of the gas mixture before any
combustion has taken place).

The electric sparky when produced by the induction coil and iftllowed
to pass b«^tween the electrodes held at M, shows very interesting and in-
structive phenomena ; of which, however, it would be very difficult to
give a clear idea in a few words.

The sound-wave in air corresponding to each separate spark is, like
the sound, a single impulse; it is beautifully visible as a bright circle or
ellipse around the source of sound, moving regularly from the center
outward. A succession of sparks in regular intervals gives moving circles
of light The spark from a Leyden jar gives a sharp sound, and one in-
creasing circle of light one sound-wave. That this is a sound-wave,
Tdpler proved by trying in vain to blow it aside by a feeble current of
air, and also by finding it to progress more rapidly in heated air. But
more interesting yet is his experiment on the reflected sound-wave. Sus-
pending a glass plate from the brass electrodes by means of corks, he
flaw in lines of light precisely the same phenomenon which we observed
when circular waves of a liquid meet a plane wall : they are reflected as
circles described from a point as far behind the obstacle as the origin of
the wave is in front of the same. By having the electrodes either in the
axis of the apparatus or at right angles to it, Tdpler found that in the
first case the lines were elliptical, in the latter circular : so that the wave
is a surface of revolution around the electrodes as an axis.

It may well be said that by means of Topler's apparatus we see the
sound ; in Chladni^s and even in Eundt's experiments we only see the
motion imparted by air to some other body, not the motion of the air
itself. For the application of this method to the microscope, see Tdpler's
article in Pogg. Ann. o. h.

11. On atomic heat and the specific gravity of gases, — Gustav Sobmidt,
known by his theoretical labors on heat and the steam-engine,* has pub-
lished an article on ^Atom-v>&rme^^ (the specific heat of atoms, which we
abbreviate as above) ; but only the appendix to the article, treating on
the specific gravity of gases, seems to contain any addition to our

* Theorle der DampfmaschineD. Freiberg, 1861.

Digitized by


Scientific Intelligence,

The atomic faeat, ut, of an element (=^c, where ^ ie the atomic weight
ftnd c the specific heat of the substance), he endeavors to prove to be
t0=an, where «t is a constant, the same for all the elements, and n the
characteristic of the element. Therefore, if a represents the number of
atoms in any compound, and if the atomic heat of the compound equals
the 9um of the atomic heat of the several atoms, it follows that
to=:gc=z2a . an:na2arL

Schmidt makes a number of suppositions in regard to a and hence

obtains diflferent values of n. For solidt he takes either asi - =l'0666


or a-=0'8 ; for gases he adopts a=0'80y and correspondingly for n.


eolidi. Gum. |


a=0-8 1 a=0-86 |



H, 0, B, SI




CI, Br, I, and metals



0,0, N,S
Br, 01

As, So, Ti




CI, Br, I, and metals

A glance at this table is enough to convince any one that this suppo-
sition cannot be correct. We need only to calculate the values toz=an
from this table, and compare them with those used by Eopp, to see that
the so-called ^^ characteristic^ is essentially characterized by having no
character whatever.

We should not have referred to this memoir if we had not found the
closing pages thereof to contain a most accurate theoretical determina-
tion of the specific gravity S of all permanent gases, and of vapors above
their boiling points (that of atmospheric air =1). If ^ be the weight of
a molecule of eqnai volume with HGl or NH^, he finds ^=0-0346832^,
with a possible error in the coefficient of less than one-fifth per cent, and
an actual error of less than one-fiftieth per cent. To find this very im-
portant number he makes use of a relation from the mechanical Uieory
of heat and the following quantities from experiments : pressure of atmos-
phere, specific gravity of air, coefficient of expansion of air, and the per-
centage composition of the atmosphere with 02^=32 and N2:=28 : all
fundamental quantities determined by Regnault and others with most
scrupulous care ; by adopting the specific gravity of oxygen as determined
by Begnault^l*1056.3) the atmosphere would contain 23*57 instead of
20'81 per cent of oxygen. This shows that the calculated density of
oxygen (1*1099) is much more reliable than the observed one.

He finds furthenmore, the mechanical equivalent of heat ib=422*06
meterkilograms (for kilogram-Centigrade) instead of Joule's, 423*54,

A=7 ; the specific heat of aqueous vapor =H»0 0*3822. As a fur-

.T 9 the specific heat of aqueous vapor :

ther consequence from an empirical relation, g{G'^G)^=:2, (where C
specific heat by constant pressure, rational specific heat) he finds finally

vthe Gay-Lussac Warioite's law expressible in -^^^2 ; or, by heating a

Digitized by


Chemistry and Physics. 89S

molecule of volumej V, of any gas under any constant pressure, p, at any

temperature, T (T<^=-=2'5r3'' C. below 0** C.) ttoo calorics (or aniU of

heat) are necessary to overcome the external work for each degree C» the
temperature is raised. The molecular weight and the unit of heat must
of course refer to the same unit of weight — Siizungnberiehte, Wien,
1865, Hi, 417-452; Corresp. Blatt d. naturf. Vereins, Riga, 1864, xiv,
35-44; L'InsHtut, 1866, p. 191. o. B.

12. Expansion of water below 4® C, — Dr. WEmNSR has, by means of
water thermometers (bulb a cylinder 11mm. diameter, 100mm. high,
tube not less than 1mm.), determined this expansion with great care,
starting in four independent series, with four different water-thermome-
ters from the temperature of 4" C. to 0** C. and then to —9** or —10" C.
From each series he calculates by a formula of form V=l-|-a<-|"^^'~h
ct^ the expansion for each degree C, the volume at +4" 0. being unity.

By comparing the four series I find a very close correspondence except
for — 4" C, where the first series deviates 37 millionths ; on referring to
the formula, the stated value, 513 millionths, is found to be 550*6, agree-
ing with the other three in the sixth decimal. Taking the mean from
the four values given by Weidner we obtain the following volumes of



+ 40C.




+ 8«




+ 2«




+ 1 "







- 1 «




— 2 «




- 8 «




- 4 «




- 6 «




- 6 «




- 7 «




- 8 "




^ 9 «




-10 «



Above zero Weidner's volumes are greater; but between 0" and —6^ C.
the three experimenters correspond well enough. — Fogg* Ann., 1866,
XXIX, 300-308. G. a.

IS. Specific heat of soils. — L. Pfaunblbr has determined the specific
heat of seventeen soils with great care. The accuracy of the method
with a modified Regnault's apparatus, was proved by determining the
specific heat of water and of Iceland spar. The first showed the same
increase as found by Regnault ; the second gave, by ten independent de-
terminations on the same piece, successively more and more subdivided,
0*20588, with a probable error of only 0*00006. This agrees with Reg-
nault's results, 0*20694 (from eighteen determinations), and Eopp% 0*206
^frora four determinations), thus disproving that of Pape and Neumann
(0*202). For soils he finds the specific heat between one-fifth and om-
iuUf (0*1923 and 0*5069) ; the most common value is 0*25 to 0*30.

Soib firee from humus have the lowest spedfie heat, whether they con-

Digitized by


39 i Scientific Intelligence,

Aist of sand or lime ; this might have been concluded from the fact that
calcite and quartz have almost the same specific heat, viz., 0*20 and ()'19.
The more rich a soil in humus, the higher is its specific heat Thus peat
was found to have 0*507, and a soil, ver^ rich in humus, from Eaiserstein,
gave 0*4143. Since water also must increase the specific heat of a soil,
we may conclude that loamy soils also have a high specific heat.

So great a variation in so important a physical property of soils is of
considerable importance to agriculture. A plant sensitive to changes in
temperature may be unable to grow on soils of low specific heat, bow-
ever excellent this soil might l^ in other respects. — Jrog^, Ann,, 1866,.
cxxix, 102-135. o. H.

14. The spectrum of the electrical hrush and glow has been obaerved
by A. ScHiMKow. While the spectrum of the spark is affected by and

Online LibraryJohn AlmonThe American journal of science and arts → online text (page 45 of 102)