Sir William Crookes.

The Chemical news and journal of industrial science; with which ..., Volume 79 online

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RbXily*^} Apparatus /or the BsHmattan of Halogens and of Ammonia,



85



THE CHEMICAL NEWS.

Vol. LXXIX., No. 2048.



MODIPIBD FORMS OP APPARATUS

FOR THE ESTIMATION OP HALOGENS AND

OF AMMONIA.

Bf F. D. CHATTAWAY, M.A.. and K. J. P. ORTON. M.A.

The apparatai ordiotrily figured in text- books for ate 10
the volumetric estimation of a halogen or of ammonia is
not very convenient. We have recently had occasion to
make a large number of such analyses, and have employed
modifications which may prove of service to other
chemists.

ApparMuifQf Bstimaiion of Hahgini by DiiiiUing thsm

into a Solution of Poiatsium Jodidu

This (Fig. I) consists of a flask of about 300 c.c. capacity,

closed by a hollow ground.glass stopper into which are

two tubes, one of narrow bore leading to the



bottom of the flask, end the other of wider bore, blown
into A bulb above the stopper, conneding the flask with %
U'lnbe which is attached by its other limb to an absorption
apparatus*

The parts are all carefully ground together, so Chat the
evolved halogen can never come Into contaft with any
oxtdisable material— an absolutelv essential point if great
accuracy be needed. The disttlfation is conduAed in a
slow stream of carbon dioxide, led to the bottom of the
flask by the fine tube. This ensures regular boiling, io
that the distillation reauires little attention, and prevents
any oxidation of the hydriodic acid, which, when acid
solutions are distilled, is always liberated from the
potassium iodide used to retain the produd. As a farther
prote^ion it is advisable to add a little finely-powdered
calcium carbonate to the potassium iodide solution.

The U-tube is cooled in a beaker of water, and it is well
to wrap a piece of filter-paper round the limb heated by
the steam, keeping it moist by allowing it to dip below the
surface. The apparatus is somewhat cheaper and very
little less efficient if the final absorption bulbs, which are
used to prevent any possible loss of iodine, are conneAed
with the U-tube by an indiarubber stopper, bat the distil-
lation cannot then be carried out so quickly.




l^^-I? ACTUAL SIZE

Fio. I.



ik^^-i? ACTUAL SIZE



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^



Production of Chlorates by Electrolysis.



1 Feb. ^,1899.



Apparatus for Eiiimaiion of Ammonia or of Nilrati$ and
Niiritis by Rtduction. '

ThU (Fig. 2) is a modificatioa of Harcourt't apparatus
iyourn. Chtm» 5o>., xv., 385).

The ends of the bent inner lube of the condenser and
of the tabe conneding the distilFing flasks are cat or
ground olT at a sharp, angle, and in each, except the
delivery tube into the second flask, a small hole is blown
about 2 cm. below the stopper.

The inner condenser-tube is bent at its lower end, so as
to pass vertically into a 300 c.c. flask which serves as a
receiver. Through the stopper of this flask alio passes
the stem of a tap funnel which is half filled with glass



The figure represents the reservoir bottle, c, the dis*
solving flask, a, and the safety anangement, b, wheo the
operation is procetding as usual. The latter piece of
apparatus is one of several forms which have been tried.
It is particularly chosen for illustration because it can be
made to serve a double purpose.

A verbal description is hardly necessary. The drawn
out tube is held firmly, but not air-tight, in the oeck of
theiioille; its tip dips just below the surface of the mer-
cury. No air can be drawn through this arrangement,
because the tube is so narrowed that a considerable
pressure can be indicated without sensibly lowering the
general level of mercury ; but if from any cause the water



beadf . Standard acid is added to the receiver through 1 runs back into c, the compressed air finds escape by



the tap funnel, which serves as a very efficient scrubber.

The second flask should be boiling quietly before the
first dask containing the alkaline liquid is heated ; twenty
to thirty minutes* boiling is sufficient to complete an
ammonia distillation. On detaching the flask and
rins ng out into it the tap funnel and the end of the con*
denvertube through the small hole, the contents are ready
for titration.

. The distilling flasks in this and the preceding apparatus
are conveniently healed in cups made of thin asbestos
board, or thicker board split ; this is soaked with water,
moulded to the shape of the flask, then dried and detached.
Such cups prevent bumping in most cases.

Chemical Laboratory.
St. Bartbolomew*t Hospital, B.C.



A FILTER PUMP ACCESSORY.
By HORACE JBRVIS.

Three years ago (Chbm. News, Ixxiv., 63) there was
described an arrangement for agitating liquiott by drawing
a current of air through a series of properly fitted and ar-
ranged flasks by means of an ordinary filter-tube or pump.
The apparatus is described in connexion with its use m
dissolving steel in copper ammonium chloride solution ;
it is in this same capacity I have had experience with it.
Until a few months ago a particular filter-tube was
supplied with water from a cistern. For certain reasons
the supply had to be drawn diredly froiti the main, which,
as we were placed higher than any other users on the
tame service, caused the supply to be very irregular in
amount when the cock remained a fixed distance open.

D

>PUMP




ABC

On several occasions since the alteration was made it
has happened that the sud on has ceased, and a back
pressure has pushed^ the copper lolotion nearly, if not
altogether, into the adjacent flasks. This appears to be
caused by a sudden rush of water having no easier means
of escape than up the tube into the reservoir bottle c (see
figure). I have known a similar effeA to be due to the
e opping up of one of the inlet tubes, whereby the vacuum
became great enough to draw the water the wrong way.

From the former cause the occurrence has become fre-
quent enough to warrant special precauttoni being taken
to prevent it. Whefe the agitated Hquid would leave no
trace, did such a thing happen, some precaution seems
advisable, even if the danger appears remote.



pushing the mercury below the bottom of the drawn out
tube before the solution in the dissolving flask is pushed
beyond any desired point on the straight tube, B. (This
statement becomes less and less true as the number of
flasks are increased). There is thus no possibility of
copper solution passing from one flask to the other.

By pouring mercury into the bottle until it nearly
reaches the lower end of the larger tube D, which passes
through the doubly perforated stopper, the apparatus be-
comes also an atrangement whereby the degree of exhaustion
is kept constant. As soon as the pump is started, mercury
rises so far that the end of the tobe d is covered ; after that
varying sudtion is exaAly counterbalanced by the varying
height to which the mercury will rise.

The first of these purposes is most simply accomplished
by allowing a drawn out leg of a three-way tube, whose
other ends are attached to a and c, to pass into a bottle
containing mercury. The latter purpose, I am reminded,
is more elaborately, and perhaps better, accomplished by
a piece of apparatus used by Theo. W. Richards in con-
nexion with vapour density determinations under reduced
pressure (Cuem. News, lix.,39).



THE PRODUCTION OP CHLORATES

BY ELECTROLYSIS FROM SOLUTIONS OF

CHLORIDE OF CALCIUM.

By F. CETTBL.

The results I have obtained by the eledrolysis of solutions
of chloride of calcium confirm the indications recently
furnished by Bischoffand Foerster. The very slight import-
ance of the losses by redudion is attributed to the formation
of a thin layer of hydrate of calcium on the cathode ; thia
layer ads as a diaphragm. The eledrochemical adivity of
this slight skin does not, however, appear to depend upon
its being thick ; since, on the one hand, excellent resolu
have been obtained with an extremely thin membrane;
and, on the other hand, a diaphragm of 2 m.m. in thick-
ness was pradically without effed. The produdton— and
what is of more importance, the preservation — of s good
membrane requires great care and experience.

The following table shows the normal coarse of an
eledrolysis. The solution of chloride of calcium con-
tained 130—150 grms. of the salt per litre, and a little
milk of lime was added to precipitate the magneaia. The
density of the current was 900 ampdres per square metre
of anode and cathode ; the difference of potential varied
between 3*8 and 4 volts, and the temperature was Jnpt up
t0 75'C. "^



Daration


Usefal retam DecomDositioa








from the


0!


Rr<


ludiofl




current.


water.






Hours.


Per ceot.


Perceat.


Percent


i


718


41




a4'i


i


763


Xr4




"•3


I


78a


ia-5




9*3


3


797


165




18


5


831


12*9




40


8


81*1


xa-5




64


10


81-9


11-4




67


?a


83-3

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Web, 24, 1899* I



Estimation of Phosphoric Add in Superphosphates.



87



It Ahuuld be noted that the useful return from the cur-
rent increaees during the firti few hours, aud ihea remains
prmAically constant at about 80 per cent.

The distribution of the remaining 20 per cent between
the decomposition of water and . the rcdu^on. of the
already- formed hypochlorite is very variable.

In another experiment I obtained ; —

Useful return from the current . . 79 p^r cent

Decomposition of water 9 ,,

ReduAion • la „



These results were considered to be very satisfadory.
and I have endeavoured to utilise them for the iollowiog
purposes ; —

I. To eledrolyse chloride of calcium to form chlorate.

a. By adding chloride of potassium to precipitate
chlorate of potassium, and thus re-generate the
chloride of lime to be eleArolysed over agaib.

By following this plan 1 obtained some aUogother un-
ezpeAed results.. The presence of chloride of potassium
in the solution caused the formation of thick crusts on
the cathode. These crusts were gradually destroyed, and
at the same time free chlorine (not hypochlorous acid)
was given off simultaneously with hydrogen. I was led
to the conclusion that the charader of the deposit formed
on the cathode is such that it cannot re-dissolve with suf-
ficient rapidity to fix the chlorine. Further, the proper-
ties of this deposit are very variable. In one experiment
a. thin layer was sufficient to stop the disengagement of
chlorine; in another trial, the layer disappeared com-
pfete^y, to give place to the thick crusts 1 have just
spoken about, while at the same time chlorine was
evolved.
I By cooling the eledrolyte, 1 could often obtain crystals

of oxychloride of calcium in long needles ; and I have
every reason to believe that this substance plays an im-
portant part in the eledrolysis.
^ It is possible that the curious phenomenon I observed

on the addition of chloride of potassium to the solution
may be conneded with, not the fuimation, but ihe 8ol^-
bility of the oxychloride in the chloride of potassium, and
that the crusts which are formed on the cathode are not
the hydrate, but an insoluble oxychloride of calcium.

The eledrolysis of solutions of chloride of calcium is
farther aubjed to other disturbing influences. In one ex-
periment I performedf a quantity of chloride of copper
which bad formed on the surface of one of the cond^dors
bciyune detached from the wire and feil inio the eledro*
lytic bath, where it was transformed into oxide. This
oxide, adiog in its tutn on the hypochlorite^ decomposed
It, at the same time setiing free a quantity of oxygen.
Other analogous substances, such as the oxides of iron,
nickel, and lead, ad in a similar manner, so that all sorts
of precantiona must be constantly taken if we wish to
Jodge the cesults of an experimeq^ from a, single analysis
of the gas. ....

This point appears to be well established by the fol-
lowing ngnres, obtained by the eledrolysis of chloride of
calcinm in the presence 01 oxide of copper.

' Useful rstara from Docompotition

the carreat. of water. Redadioo.

Percent. Percent. Percent, i

Apparent •• «• 30'9 57*3 ii'9

Real 733 H7 "*o

The second— ^r true— figures were obtained by calcula-
tions based on the measurement of the oxygen given off
by the aaion of the oxide of copper during the same timt
(three minates) - the circuit being opeb. From the results
^ I have obtained I am brought to the conclusion that the
elearolytic produ^ion of chloratds is accomplished by
two distina aaions, which may, however, be sometimes
combined t—

a, 'the produaion of the chlorate by the intermediary
of the hypochlorite» The first produas formed (alkali



and chlorine) combine to form the hypochloriie. This
hypochlorite, under the further aaion of the chlorine, and
aUo by simultaneous direa oxidation, is transformed into
chlorate.

h. The produaiou of chlorate by the direa union of
the Chlorine and oxygen simultaneously set free at ihe:
anode.

In a neutral solution it is the a reaaion that predomin-
ates. In a strongly alkaline solution, the other {b) reac-
tion occurs. Finally, in a slightly alkaline solution, the
two reaa ions take place simultaneously ; it being always
understood that the density of the current is the same
in each case.

In the elearolysis of chloride of calcium in particulair,
the a reaaion is the predominating one. Similar solu-
tions show a tendency to become slightly acid on account
of the formation of free hypochlorous acid. In the case
of alkaline chlorides, the position of the elearodes and the
density of the current are the principal causes which in-
fluence both the liberation of chlorine and the formation
of a slight excess of free 9\k9Xi.^Ztitschrift fur EUctro-
chtmiit v., [1], x— 5.



THE ESTIMATION OF PHOSPHORIC ACID IN

SUPERPHOSPHATES.

By LEO VIGNON.

As is well known, the estimation of soluble phosphoric
acid in superphosphates and in chemical manures com-
prises praaically three cases : —

X. Estimation of the pho.spboric acid soluble in water. •

2. Estimation of the phosphoric acid soluble in wat^r

and the phosphoric acid soluble in citrate of am-
monia fo/^<M#r. -. ^—

3. Separate estimations of the phosphoric acid soluble

Jn water and that soluble in ciuate ofXnmOnii(.

The experiments described in this paper have to do
only with the last case!

: For the separate estimation of the phosphonc acid,
soluble in water and that soluble in citrate of ammonia
It is usual to proceed in the following manner :—

The phosphate is first exhausted with water, then the
residue is coUeaed and treated with citrate of ammonia.
We then precipitate stparattly the phosphoric acid in both
the aqueous and citrate solutions in the state of ammoniu-
magnesic phosphate. Alt these operations must be
carried out striaiy according to the rules laid down by
the Committee of Agronomic Stations and Agricultutal
Laboratories.

I have observed that if the sample contains much, phos-
phoric acid soluble in water and only a small quantity
soluble in citrate of ammonia, the precipitation of the
latter form of phosphoric acid is not always complete,
even after standing for several hours. '

Samples of superphosphates treated in the way I have
Just described have given the following results :—

X. Aftif Eight Hours,

Bone super- Mineral super-
pbotphatei. phoapbatsa.



Phosphoric acid soluble in water
II fi II citrate

Total • X5*Q9 X4*40

2. After Piftten Hours.

Phosphoric acid soluble in water 14*32

ti ,t II citrate 108



J.


^11.


lit


[4-32


I4I3


X0'20


077


0*27


310



I4I3
045



13-30



.10*20
3i« J



Total X5-4Q . I4'58 .1338

The results are again different if mt first mix the*
aqueous solution with the solution obtained by 'exhausting '



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'8B



London Water Supply.



I



basMteAL KbwW
Fob. a4f x*99>



with citrate of ammonia. In fad, for the saperphosphate
examined I obtained after standing for twelve boars : —

Booe super- MioermI loper-
pbotpbAtM. photpbatM.



II.



III.



X7'79 «3'94 U'9i



Phosphoric acid soluble in water
and in citrate (mixed) • • • •

From which we dednce— >

Pkosphorie Acid SolubU in Citrati,

By direa estimation • i*o8 045 3'>8

By difference . •• • 3*47 o*8z 3*71

We are thns liable, by dired estimation, to find too low
figures for the phosphoric acid soluble in the citrate when
it IS only present in small qnantities. It is true that the
formation of the ammonio-magnesic phosphate may be
helped by continuous mechanical agitation, and by raising
the temperature to 35—30*; but these conditions com-
plicate the analysis, and besides may not always be con-
venient to apply. The method of estimation by difference
is more to be trusted.

It is easy to understand why the ammonio-magnesic
phosphate, by reason of its mass, has a greater tendency
to come down integrally in a shorter time in the aqueous
and citrate mixture than in the citrate alone, which
might be very poor in phosphoric acid.

To sum up, for $iparai4 estimations, in a snperphos*
phate or in a manure, of phosphoric acid soluble in water
and the same soluble in citrate of ammonia, it is better to
estimate the phosphoric acid soluble in water dirtctly^ the
phosphoric acid soluble both in water and citrate of am-
monia togitkif, and the phosphoric acid soluble in citrate
of ammonia only by diffsrtncs.^BulL Soc. Chim; Series 3,
▼oh xik.-kx*. No. 20-21.



THE PURIFICATION OF ACETYLENE.
By P. WOLPP»

tiARDLV a day passes without some new method for the
purification of acetylene being proposed with the objed
of preventing the formation of smoke, which always
accompanies the combustion of this gas. This smoke is
due to the polymerisation of the acetylene itself; it can
therefore only be prevented by using special burners, and
not by further purifying an already sufficiently pure gas.

Ferric hydrate, Laming*s mixture, or any other
analogous produd, can be used for absorbing the ammonia
and the sulphuretted hydrogen ; but they do not absorb
the photphoretted hydrogen, which really constitutes the
only objediooable imparity. To absorb this gas, Lunge
and Cedercreuts have proposed the use of chloride oi lime,
which plays the part of an oxtditing agent {youm. Soc.
Chtm, Ind., 1897. P* 1046).

Now, previous experiments showed the author that the
adion of chloride of lime on acetylene is accompanied by
small explosions, following the formation of chloride of
nitrogen at the expense of the chlorine of the chloride of
lime and of the nitrogen of the ammonia which is always
to be found in acetylene. It is therefore necessary to
free the acetylene of its ammonia before purifying it
with chloride of lime. This can be thoroughly done by
simply washing with water. Chloride of lime can abe«irb
phosphide of hydrogen at the same time as the sulphydric
gas without danger. Thus purified, acetylene possesses
only a faint ethereal odour, which should, if possible, be
accentuated, for facilitating the detedion of leaks. This
can be effeded by mixing with it a small quantity of
carbylamine or acetate of amyl, or, again, by simply
passing it over carbide of calcium. The ad of drying by
contad with this body causes the liberation of a small
quantity of raw acetylene, which communicates sufficient
smell without contaminating it to any appreciable extent*



Pure acetylene does not attack copper or its alloys, bat
any trace of imparities quickly causes brown stains to
appear on polished bronse ornaments. These stains are
formed of phosphide, and not acetylide, of copper. —
Chimikif Ziitung, xxii., [a8], p. 281.



LONDON WATER SUPPLY.

RiPORT ON THB COMPOtlTION AND QUALITY OP DaILY
SaMPLBS op THB WaTBR SUPPLIED TO LONDON

FOR THB Month Ending January 31ST, 1899.

By SIR WILLIAM CROOKBS, F.R.8.,

and

PROFESSOR DBWAR, P.R.S.

To Major-Gbnbral A. Db Couiicy Scott, R.E.,
Water BMamimr, Metropolis Water Act, X871.

London, Fsbraary xoth, 1899.
Sir, — We submit herewith, at the request of the
Diredors, the results of our analyses of the 182 samples
of water coUeAed by us during the past month, at the
several places and on the several days indicated, from the
mains of the London Water Companies taking their
supply from the Thames and Lea.

In Table I. we have recorded the analyses in detail of
samples, one taken daily, from Jan. xst to Jan. 3zst
inclusive. The parity of the water, in respeA to organic
matter, has been determined by the Oxygen and Com-
bustion processes; and the results of our analvses by
these methods are stated in Columns XIV. to XVIH.

We have recorded in Table 11. the tint of the several
samples of water, as determined by the colour-meter
described in previous reports.

In Table III. we have recorded the oxygen required to
oxidise the organic matter in all the samples submitted
to analysis.

Of the 182 samples examined by as daring the month,
all were found to be clear, bright, and well filtered.

There has been a considerable excess of rain during
during January, the adual fall at Oxford was 2 85 inches,
the average fall for the past thirty years is 2*16 inches ;
this gives an excess of 0*69 inch, or 31*9 per cent.

Our baderiological examinations of 255 samples have
given the results recorded in the following uble; we have
also examined 37 other samples, from special wells, stand-
pipes, &c., making a total of 292 samples in all :—

Microbes
perc.c

New River, unfiltered (mean of 25 samples) •• 1651

New River, filtered (mean of 25 samples) •• ix

Thamesi unfiltered (mean of 25 samples) • • 22764
Thames water, from the clear water wells of
five Thames-derived supplies (mean ol 128

samples) 35

Ditto ditto highest 260

Ditto ditto • •• lowest o

River Lea, unfiltered (mean of 26 samples) •• 4576
River Lea, from the Bast London Company's

clear water well (mean of 26 samples) • • • 14

The above figures show the average baAeriological con-
dition of the London waters to be highly satisfaAory,
being only 35 microbes per cubic centimetre although the
crude Thames water contained upwards of 22,000 per c.c;
this shows a very high efficiency of filtration. It will be
observed that one sample gave an abnormal result, namely,
260 microbes per c.c. This was caused by a temporary
defea in a filter, which was immediately deteAed by us,
and at once attended to*

We are. Sir,

Your obedient Servants,

William CrookbSi
Jambs Dbwar*



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bll|tMICAL^IIWt,l
Feb. 24. 1899. f



fetrabromides of Zirconium and thorium.



8.



DERIVATIVES OF THE TETRABROMIDES OF

ZIRCONIUM AND THORIUM.*

By J. MERRITT MATTHEWS.

I.— Introduction.
This inveBtigation was taken up as an adjund to a pre-
ceding reiearcb (Jourm, Am. Chtm, Soc,^ xx,, p. 815;
Chbm. News, Ixxii., p. 6) on the Derivatives of the Tetra-
chloride!.

Only derivatives with the foar most t3rptcal amines-
ammonia, ethylamine, aniline, and pyridine— were pre-
pared, as it was considered needless to extend the investi-
gation further, when the aim was only to prove a general
readion between the amine bases and the tetrahalides of
t|ie fourth group.

The anhydroas tetrabromides of sirconiom and thorium
were prepared in a manner exadly similar to their tetra-
chlorides, dry bromine vapours in a current of carbon di-
oxide gas being tubstitoted for chlorine (Mellis, ZUchr.
Chim,, [a] , vi.i 296 ; Troost and Ouvrard, Ann, Chim,
Phys.t 1.6], avii., 229).

Owing to the slight solubility of the tetrabromides in
any of the usual organic solvents, the reagents in all cases
were added to the dry salts, any excess being removed by
washing the produd so formed with ether.

Several attempts were made to prepare the tetrabromide
of lead, proceeding in a manner analogous to that used in
the preparation of the tetrachloride, but without Success.

a.— Tub Aminx Dbrivativbs.

A. A'nwutnia.

«• Zireonium TttrabromitU, ZrBr4.4NH3.— On passing



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