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only 4 cwts. of fuel are used for every ton of the waste
liquor treated. The plant is not costly, and, as it works
at a low temperature, the wear and tear are small. No
skilled labour is employed, one labourer being sufficient
to attend to a plant of the largest size. According to the
adual experience of a firm who have worked the process
since July, 1889, the recovery of one ton of acid of a
quality fit for use in picklin|; costs eight shillings.

Few processes for utilising waste produda can show
such good results.

Digitized by


Cbbmical Nbwi, I
Feb. ao, tSgi. |

Chemical Notices from Foreign Sources.


Biographisch'Kttiransehii Handwdrtirbuch der Wtsstn-
sckaftlkh h€dtuUndtn Chsmiktr. (" Biographical-
Literary Didionary of ChemiBtB who are Scientifically
of Importance.*') Herauigegebon von Dr. Carl
ScHABDLBR. Berlin : R. FriecUaender and Sohn.
It sometimes happens that we feel uncertain as to the
time and place when some chemist " flourished," as to his
researches and discoveries, the works he wrote, or the
positions he filled. Dr. Schaedler's compad little work
meets this want in a very convenient manner. The
notices of the various chemists here mentioned are neces-
sarily brief, but they are almost without exception accu-
rate. The work is charaderised of a spirit of fairness
and impartiality. There is no tendency to unduly exalt
German savantt at the cost of their French or English
contemporaries. A similar impartiality is observed as
between the different tendencies which spring up within
the field of chemical science. We notice with pleasure
that the author pronounces Baum6*s hydrometer •• errati-
cal.** Chemists who. read German will find this work
exceedingly useful.





To the Editor of the Chemical News,
SiR^— Post hoc ergo propter hoc is but a prima facie argu-
ment, and surely not one upon which agitators may be
allowed to claim that they have brought about a so-called
reform.^I am, &c.,


other analysts, to whom, like eveiyoae else worthy of
existence, time is money.— I am, ftc.,


Mioerslocical Laboratoryl

Uaivenlty of Bdiabargh.

Feb. 14, Z891.


To the Editor of the Chemica/ News.
Sir,— -In view of the several favourable criticisms of my
*• Manual of Assaying," which have appeared in the Chbm.
News from time to time, I trust yoo will insert this pro«
test against the ** reprint " noticed in the issue for Dec. 5,
1890. This " copy ** is issued entirely without the
authority of my publishers or myself, and could not
possibly have been put forward had there been any Inter*
national Copyright Law. The fad that many American

Eublishers have ** pirated " English publications coold
ardly be tendered as an apology for this re-issue. The
reprint is backed as ** Brown and Qrifflths.*' The adual
contribution of Prof. Griffiths is one chapter on *< Fuels,**
and, presumably, the slight revision, consisting of the elimi*
nation of the personal ** I " in favour of the editorial *' we,"
and the substitution of English financial values for
American ones.

While we may not exped the utmost ideas of honour
from publishers, ceruinly we do exped the highest order
of aaion from scientists ; and it was therefore with
feelings the most mingled, of surprise, sorrow, and indig-
nation, that 1 saw the name of so distinguished a man as
Prof. Griffiths attached to the book I protest against.— I
am, &c.,

W. Lbb Brown.
Author of Brown's *' Manual of Assaying.*'

Office of North- westam Gas- Light

and Coke Co., Evanstoo, lU.

Jan. 27, 1891.


To the Editor of the Chemical News,
Sift,— 'I venture to suggest that the Jubilee of the Chemical
Society be in part celebrated by the foundation of a
Benevolent Fund for the relief of distressed Fellows and
others, and of their widows and orphans ; to be ad-
ministered by the Society, alone or in conjundion with
the Institute of Chemistry and the Society of Chemical

I will gladly give £50 if nineteen other subscribers will
each contribute a like sum. The few wealthy chemists
amongst us would probably promise much larger amounts.

The Fund once started, doubtless many chemists
would contribute a guinea annually. — I am, &c.,

John Attfibld.

Watford, Feb. I7f »89i.


To the Editor of the Chemical News,
Sir,— While analysing qualitatively a mixture containing
iodides and bromides the other day, it occurred to me, as
my starched paper (prepared according to the careful
direaions of the text-books) was done, and I was dism-
clined to break off my work to make more, that I might
find an efficient substitute in ordinary white writing-paper.
I tried this after moistening with water, and found to my
delight that it did as well as the best starch-paper that
ever was prepared ; and why not, seeing that in the pro-
cess of manufaaure, writing or, indeed, any common
paper is finnshed with size which contams a notable
quantity of starch ? . , .^. . , j j

As I had never before heard of this simple and ready
substitute, I thought the notice of it might be welcome to




NoTB.— All decreet of temperatare are Ceaticntde unless otherwise

Comptes Rendus Hebdomadaires des Siances, detAcadhnu
des Sciences. Vol. cxii., January 26, 1891.

Contributions to the History of the Nitrogenoos
Principles Contained in Vegetable Soils.— M. Ber-
thelot and G. Andr6.— The author studies the adion of
acid and alkaline solvents upon the organic nitrogen
(previously insoluble) contained in vegetable soils. By
the prolonged adion of alkalies we may render soluble, in
26 hours* treatment in the water-bath, 93*6 per cent •!
the organic nitrogen of soils. By the successive aAion
of alkalies and acids we may extrad 95*5 per cent. If we
begin with dilute hydrochloric acid, 71 per cent of the
nitrogen are rendered soluble by 13 hours' treatment in
the water- bath, and the subsequent adion of dilute
potassa brings the total thus made soluble up to 91 per
cent. These experiments show how the insoluble nitro-
gen conuined in the huroic compounds is gradually ren-
dered soluble and capable of assimilation. The adion of
plants is certainly not comparable to that of the alkalies
and acids used in the author's experiments ; but the
natural agents compensate for their smaller energy by
their prolonged adion.

New Observations on the Volatile Nitrogenous
Compounds given off by Vegetable Mould. — M. Ber-
thelot.— The exhalation of nitrogenous produds proceeds
as long as the earth is humid. If it is dry the phenomenon
in question is beyond comparison slower, though it still

Digitized by



Meetings for the Week.


I Feb. ao, 1891.

goes 00. The nitrogen contained in the volatile organic
compounds given off by sandy clasrs is alwa3rs much
greater in quantity than that escaping as ammonia.
From a true vegetable soil the quantities are equal.

Experiment on the Synthesis of Proteic Com-
pounds.— P. Schutsenberger.— This memoir will h
Inserted in full. ^

On the Application of the Meatnre of the Rota-
toiy Power to the Determination of the Compounds
Formed by Aqueous Solutions of Malic Acid with
the White Alkaline Phosphomolybdates. — D. Oemes.
—This memoir is not adapted for useful abstraaion.

The CondnAivity of Isomeric Organic Acids and
of their Salts.— Prof. Ostwald.— The author contests the
novelty or originality of the results signalised in a com-
munication by D. Berthelot (Comptes Hindus t January
5th, X891, p. 46).

Reply to Professor Ostwald.— D. Berthelot.— The
author contests the reclamation of Prof. Ostwald.

The Mordants used in Dyeing and the Theory of
Mendeleeff. — M. Prud'homroe. — This memoir will be
inserted in fiiU.

Note on Diabetes.— H. Arnand.— This paper is more
physiological than chemical in its charaAer.

Rtvu$ Ginirali des Scitncei Puns et Appiiquiis,
Vol. if., No. I, January 15, 1891.
The Artificial ReproduAion of the Ruby.— A.
Vemeuil. — M. Fr^my, in conjundion with the author,
has improved his process. He has obtained not only the
ruby but the sapphire, and even the oriental emerald, by
modifying the quantity of chrome employed. The most
suiuble temperature for the reaAion appears to be about
1350^ The largest stones obtained weigh a little more
than 75 m.grms., or one-third of a carat; hot he hopes,
by working on a larger scale, to produce specimens of one
or two carats.

Rtvue Unhtrselie dei Minrs et de la Mttallurgie,
Vol. xii., No. 2.
This issue contains no chemical matter.


Monday, 23rd.— Medical, 8.30.

Society of Arts, 8. «• The Elearic Transmistion

of Power," by Gisbert Kapp.
TUBBDAV, a4th.— Inetitnte of Civil Engineera, 8.

Royal iDttitntioo, 3. " The Stmanre and Fuoc-

tiont of the Nervous System," by Prof. ViAor
Horsley, F.R.S.

- Royal Medical and Chirurgical, 8.30.
Wbdnbsday, 25tb.— Society of Arts, 8. ** Colonisation and its

Listiutions," by E. J. Raveostein.

- Geological, 8.
Thursday, a6th.— Royal, 4.30.

'— Institute of Bledtrical Bneineera, 8.

Rw\ Institution, 3. "The Position of LuUi,

Purcell, and Scarlatti in the History of the
Opera,*' by Professor C. Hubert H. Parry.

Society of Arts, 4.30. *• Ths Economic Develop-

ment (tf Siam," by Robert Gordon.
Fbiday, aTth.— Royal Institution, 9. •• The Art of Adting," by
Percy FiUgeratd.

Society of Arts, 4 30. " The Science of Colour," by

Captain Abney.

Physical, 5. (i) " Proof of the Generality of CerUin

Pormulc PuUished for a Special Case by Mr.
Blakesley ; Tests of a Transformer,** by Prof. W.
B. Ayrtoo snd Mr. J. F. Taylor. (2) ** Further
Contiibutions to Dynamometry," by Mr. T. H.
Blakesley. (3) Note on KleArostatic Watt-
meters,** by Mr. Swinburne. (4) ** Interference
with Alternating CurreDU,'*by Prof. W. B. Ayrton
and Mr. Sumpner.
Saturda^t, 2Zth.— Royal Institution. 3. ** The Forces of Cohesion,*'
by The Right Hon. Lord Rayleigh.







Wee 81/6. 12 Parts, 2/6 M,

atfitorlal Worlc upon this n-
vtoioa hmm beMi Sa metlve pro^Fnmm
f or OTM* 10 TMurs. Wo fewer tbui
100 JMitorlal lAbonroro hmw%
boon onrMT^A upon ity and oror
£00,000 WM ozpendod In its pro-
porattai before tbe firot oopjr was

Pmpeetu eee Free on A ppUoBUon.




1883 TO 1888.

Horace KobchliNi of Loerrach, in the German Brapire, haa
applied for leave to amend the Specification of the Letters Patent
No. 4899 of 1881 granted to John Imray for '* Improvements in the
manufafkure of Colouring Matters."

Particulars of the proposed Amendment were set forth io tbe IUns>
trated Official Journal (Patents), issued on the nth February. 1891.

Anv person may give notice (on Form G) at the Patent Office, as.
Sontbampton Buildings, London, W.C. of opposition to the Amend-
ment within one calendar month from the date of the said Journal.
(Signed) H. READER LACK,

ater-Glass, or Soluble Silicates of Soda

and Potash, in Urge or small quantitiea, and sither aolid
or in solution, at ROBERT RUMNBY'S. Ardwick Cbemioal
Works, Msnchester.

Silicates of Soda and Potash in the state ol
Soluble GUss, or in CONCENTRATED SOLUTION of first
quality, suited for the Maoufadture of Soap and other purpoeae,
supplied on best terms by W. GOSSAGE and Sons, Soap
Works, Widnes, Lancaahire.

London Agenia, COSTS and Co., 19 and ao. Water Lane, Towsr
Street, E.w , who bold stock ready for delivery.

Digitized by



Feb. 27. 189X. I

A Simple Electrical Saw.



Vol. LXIII , No. 1631.

By ProfeMor V. SCHUMANN.

I HAVB unfortunately not been able to continue my
spedroacopic photographs on account of the severe
weather; but I have been able to carry on the photo-
chemical part of my investigations, and not without some
results. I have studied the absorption spedrum of AgBr
at higher temperatures, and have found that melted AgBr
has a very dense absorption band near ** D,** and if
heated si ill more strongly it absorbs almost all the rays
of the visible speArum. In presence of Agl all the
maxima of AgBr are displaced towards the red. This
displacement is not the same in all maxima, but increases
with their wavelength. This refers also to the maximum
of illumination, which appears at the wave-length 630.
The circumstance that the dark rays efifed the absorption
of the luminous rays, whereby probably the photographic
sensitiveness is increased, will help me to photograph the
infra-red. 1 purpose observing this region with the aid
of my fluorite train. I exped a good result from the tise
of fluor-spar, because it possesses a distinguished dia-
thermance as regards refradion and dispersion, lind is
therefore less affeded by heat than any other optical
medium. I renounce rock'Salt because its transparence,
as its refradive planes become dim, is not sufficiently
constant, and does not suffice for permanent insolation,
whatever its diathermance may be when freshly polished.
AgBr displays very peculiar strudures. I have latterly
been able to obtain it in the shape of the fig cadus
{Opuntia)^ certainly only in a tender microscopic jform. I
can distinguish these strudures only with apochromatic
objed-glasses, and with the rays of the illuminating lens
falling at right angles to the objedive axis. All my apo-
chromatic lenses have been obtained from the workshops
of Carl Zeiss, of Jena.

H. W. Vogel, in opposition to Abney, maintains that
there exist two modifications of AgBr photographically
distind. One of them, if previously dried and if it had
been precipitated in alcohol, can not be suspended in
gelatin. The other, it is alleged, which has been pre-
cipitated from watery solutions, can, on the contrary, not
be diffused in collodion. Extended experiments have
convinced me that no such difference exists. It may
easily happen that the phenomenon observed by Herr
Vogel is manifested, especially if too high a temperature
has been used in drying the precipitate. AgBr always
becomes incapable of suspension if dried in hot air. This
is the case whether it has been precipitated from alcohol
or from water. If one precipitate has been treated at a
much higher temperature than another, the phenomenon
reported by Herr Vogel may easily have been manifested.
This, in fad, happened to me in the outset of my
experiments on this subjed ; but on going to work more
cautiously, and drying both precipitates auite equally, at
the respedive temperatures of is", So* and x6o% I arrived
at opposite results.

At 15" the aqueous and the alcoholic AgBr were found
capable of suspension in collodion and in gelatin. At 60*
the capability of suspension of both is much reduced, and
at 160" I attempted in vain to emulsify AgBr. I cannot,
therefoie, adroit the statements of Vogel, the less as, on
the other hand, his allegation that gelatin is only a
feeble sensitiser in my recent series of experiments,

* Extradt from a letter to the Editor.

encoimters still stronger contradldions. I shall at an
early date demonstrate that gelatin is abtdutely a
powerful sensitiser.

I have likewise been unable to deted a spedral differ*
ence of the two precipitates when they are suspended In
gelatin. In all proofs there appeared the same spedrum
which the ordinary silver-bromide gelatins display. The
slieht displacements which occur in my spedrograms are
solely due to atmospheric fluduations. I have not yet
succeeded in a simultaneous and contiguous illumination
of both emulsions, and it might hence be inferred that the
photographic adion of the sunlip^ht in my proofs had varied
exceptionally, and thus occasioned the difference from
the observations of Herr Vogel. But however justifiable
such an argument might seem, its validity is at once
enfeebled by the circumstance that the spedral proofs from
both emulsions were taken in rapid succession. Hence
so considerable a displacement as Vogel calls is exceed-
ingly improbable. On the other hand, it is not conceivable
that my instrument can have occasioned the discrepancy.
I have in these operations used only the most accurate
and sensitive spedrographic apparatus which my cabinet

By H. N. WARRBN, ReMarch Aoalytt.

Whbnxvbr a powerful eledrical circuit is closed by a
platinum wire of suitable dimensions, the well-known
heating effed of the same is at once manifested ; ytt no
one seems to have been struck with the idea that the
simple heated wire may be employed as a most effedive
disintegrator of tlie hardest organic compounds. A similar
but more convenient article may be construded as follows.
It consists of two upright pieces of very stout brass or
copper wire, conneded at the lower extremities by a non-
conduding medium, while across the top is secured a
piece of moderately thin platinum wire. On thus con-
neding the apparatus by means of side binding screws to
the terminals of about four Bunsen batteries, the platinum
wire at once becomes heated to bright redness, and will
be found to cleave the hardest wood with great facility,
insomuch that a large number of useful appliances may
be thus manufadured in a short space of time. Owing,
however, to the platinum wire frequently breaking, pro-
bably on account of its intimate contad with the cart>on,
whilst at an elevated temperature, the author has devised
and used with advantage a modified wire, formed by
depositing metallic platinum upon fine steel wire, by
exposing that substance to the adion of a slow eledriciu
current, in contad with an ethereal solution of platinic

Bverton Research Laboratory,

z8, Albioo Street, Bverton, Liverpool.

Appointment. — The Professor of Agriculture at the
Royal Agricultural College, Cirencester, Professor James
Muir, M.R.A.C., F.C.S., has been promoted to the newly
endowed Chair of Agriculture at the Yorkshire College,
Leeds. Mr. Muir has had a distinguished career both as
student and ledurer, and the Leeds College is to be
congratulated at having secured his services.

International Congress of Geologists. — We learn
that the 5th meeting of the Congress will be held at
Washington, on August 26th next. Persons wishing to
be present are requested to announce their intention to
the Secretary's Office, 1330 F. St., Washington, D.C.
The fee is 2I dollars. Special reduced rates will be
charged by the steamship lines from Europe, and by
the railway companies on occasion of the geological.


Digitized by



Electricity in Transitu : from Plenum to Vacuum.

{ Chkhical Ntwt,
I Feb. ay, xSgt.




President of the Institution of Blearical Bngineeri.

(Cootinaed from p. 93).

Phosphorescence in High Vacua,
I HAVB already pointed out that the molecular motions
rendered visible in a vacuum tube are not the motions of
molecules under ordinary condition, but are compounded
of these ordinary or kinetic motions and the extra motion
due to the eledrical impetus.

Experiments show that in such tubes a few molecules
may traverse more than a hundred times the mean free
path, with a correspondingly increased velocity, until they
are arrested b;^ collisions. Indeed, the molecular free
path may vary in one and the same tube, and at one and
the same degree of exhaustion.

Very many bodies, such as ruby, diamond, emerald,
alumina, yttria, samaria, and a large class of earthy oxides
and sulphides, phosphoresce in vacuum tubes when placed
in the path of the stream of ele^rified molecules proceed-
ing from the negative pole. The composition of the

numerous experiments I find that bodies will phos-
phoresce in aAual contad with the negative pole.

This is only a temporary phenomenon, and ceases
entirely when the exhaustion is pushed to a very high
point. The experiment is pne scarcely possible to exhibit
to an audience, so I must content myself with describing
it. A U-tube, shown in Fig. 25, has a flat aluminium
pole, in the form of a disk, at each end, both coated with
a paint of phosphorescent yttria. As the rarefadion ap-
proaches about o'5 m.m. the surface of the negative pole
'A becomes faintly phosphorescent. On continuing the
exhaustion this luminosity rapidly diminishes, not only in
intensity, but in extent, cohtraSing more and more from
the edge of the disk, until ultimately it is visible only as
a bright spot in the centre. This fad does not prop a
recent theory, that as the exhaustion gets higher the dis-
charge leaves the centre of the pole, and takes place only
between the edge and the walls of the tube.

If the exhauRtion is further pushed, then at the point
where tlie surface of the negative pole ceases to be
luminous, the material on the positive pole, b, commences
to phosphoresce, increasing in intensity until the tube re-
fuses to condud, its greatest brilliancy being just short of
this degree of exhaustion. The probable explanation ia
that the vagrant molecules I introduce in the next experi-
ment, happening to come within the sphere of influence

Fw. 24.— P. = 0*25 m.m., or 330 M.

gaseous residue present does not aifed phosphorescence ;
lius, the earth yttria phosphoresces well in the residual
vacua of atmospheric air, of oxygen, nitrogen, carbonic
anhydride, hydrogen, iodine, sulphur, and mercury.

With yttria in a vacuum tube the point of maximum
phosphorescence, as I have already pointed out, lies on
the margin of the dark space. The diagram (Pig. 24)
shows approximately the degree of phosphorescence in
different parts of a tube at an internal pressure of 0*25
ro.m., or 330 M. On the top 3P0U see the positive and
negative poles, a and e, the latter having the outline of
the dark space shown by a dotted line, c. The curve d,
B, p, shows the relative intensities of the phosphorescence
at different distances from the negative pole, and the
position inside the dark space at which phosphorescence
does not occur. The height of the curve represents the
degree of phosphorescence. 1 he most decisive eflieds of
phosphorescence are reached by making the tube so large
that the walls are outside the dark space, whilst the
material submitted to experiment is placed iust at the
edge of the dark space.

Hitherto I have spoken only of phosphorescence of sub-
stances placed under the negative pole. But from

* Inaugural Address delivered January X5th. iBqi,

of the positive pole, rush violently to it and excite phos-
phorescence in the yttria, whilst losing their negative

Loose and Erratic Molecules,
In the brief time left to me this evening I cannot touch
upon the mass of experiments made to render this result
clear, so I will at once show you a piece of apparatus
that clearly illustrates the cause of phosphorescence at
the positive pole. A drawing of this tube is shown at
Fig. 26, but let me first explain the efled I exped to ob-
tain, and then endeavour to show the adual experiment.

A c B is a U-shaped tube with terminals, a and b, at
each end ; d and e are two mica screens covered with a
phosphorescent powder, having at f and o other screens
with a small slit in front, so as to allow only a narrow

i beam of charged molecules to pass through. At first the
tube is exhausted to a pressure of 0*076 m.m., or 100 M.,
and you see how sharp and slightly divergent is the
luminous image on screen d, whilst not a trace of phos-
phorescence is to be seen on the screen b in the other limb
of the tube. Now I push the exhaustion to the highest
point short of non condudion (o'ooouyC m.m , or o*x M.),
and the phenomena change. The initial line of light on

I B becomes wider and unsteady, whilst at the gate, o, a
decided phosphorescence is observable entering the second

Digitized by


^Flh't^^^r^] Electricity in Transitu: from Plenum to Vacuum. gg

Fig. 25.

Fio. 26.

P. ■■ 0*076
or 100 M.

P, « 0*000076,
or o'l M.

Fig. 27. — P. « 0*02 m.m., or 26 M.

Online LibraryArnold BennettChemical news and journal of industrial science → online text (page 26 of 88)