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THE CHEMICAL NEWS, July 9, 1897. 



THE 



CHEMICAL NEWS 



JOURNAL OF PHYSICAL SCIENCE. 



WITH WHICH IS INCORPORAT-BD THB "CHEMICAL GAZETTE." 



% ^anxunl ai Urattttal ^J^^mistrj} 



IN ALL ITS APPLICATIONS TO 



PHARMACY, ARTS, AND MANUFACTURES. 



EDITED BY 



WILLIAM CROOKES, F.R.S,, &c. 



VOLUME LXXV.— 1897. 



LONDON : 
PUBLISHED AT THE OFFICE, 66-7, CREED LANE, LUDGATE HILL, E.C. 

AND SOLD BY ALL BOOKSELLERS. 



MDCCCXCVII, I tn (<^>*» 



{Chemical News, 
July 9, 1897 



LONDON: 

PRINTED BY EDWIN JOHN DAVEY 

6 & 7, CREED LANE, LU1>GATE HILL, 

E.C. 



THE CHEMICAL NEWS 



VOLUME LXXV. 



EDITED BY WILLIAM CROOKES, F.R.S., S'C. 



No. 1936.— JANUARY i, 1897. 



SEA-WATER MICROBES IN HIGH LATITUDES. 

By E. FRANKLAND, D.C.L., F.R.S., 
and W. T. BURGESS, F.I.C. 

The badleriology of sea-water is beginning to receive 
deserved attention from biologists, for it lies at the very 
foundation of the marine flora and fauna, as badteria 
doubtless form the initial food of higher marine organisms ; 
unless indeed there be a still more minute world of living 
matter too small for discovery by our present modes of 
investigation. 

In the year 1892, Mr. H. L. Russell examined at the 
biological station in Naples, a number of samples of sea- 
water colledted at various depths in the Bay of Naples. 
The water at or near the surface was found to contain a 
number of colonies per c.c, varying from 64 at four kilo- 
metres from land, to six at fifteen kilometres. There was, 
however, no constant relation between the numbers of 
badteria and the distance from land ; thus, at eleven kilo- 
metres from land 78 per c.c. were found. On the other hand, 
Sanlelice and de Giaxa found a rapid reduAion on receding 
from the shore, but only within a distance of three kilo- 
metres. 

In 1894 ^- Cassedebat studied the a(5tion of sea-water 
upon pathogenic organisms, and found that in sterilised 
sea-water Staphylococcus aureus died in twenty-two to 
twenty four days, Citreus in nineteen to twenty-two days, 
B. Friedldnder in thirty-five to forty days, B. Anthracis 
in twenty-one to twenty four days, B. of green diarrhaea 
in sixteen to twenty days. Spirillum Deneke in twenty- 
two to twenty-five days, Proteus vulgaris in twenty-three 
to twenty-six days. The cholera bacillus lived more than 
thirty-five days, but the typhoid bacillus died in forty- 
eight hours. 

The most complete ba(5teriological investigation of sea- 
water hitherto undertaken was made by Drs. Bernhard 
Fischer and E. Bassenge, and the results are published in 
the Centralblatt fiir Bacteriologie, 1894, "v., 657. They 
include microbe determinations in the waters of the 
Atlantic, English Channel, the Baltic, and the North Sea. 
The places where the samples were taken range from 
8° S. Lat. to 60° N., and were coUeded at various seasons 
during the celebrated Plankton expedition, and on a 
voyage to and from the West Indies. The plate cultures 
were made with gelatin containing 2 per cent of agar- 
agar dissolved in a little sterilised sea-water, and the final 



investigation of the pure cultures was made in the Baifterio- 
logical Institute at Kiel. 

The maximum number of microbes found at the surface 
was 29,400, the minimum o, and the mean in 175 samples 
1083. The mean was only surpassed 26 times ; seven 
samples developed no organisms, fifty-seven developed 
from one to twenty-five colonies, seventeen from twenty- 
six to fifty, and fourteen from fifty-one to one hundred 
colonies per c.c. The highest numbers were found near 
land, thus confirming, in this resped, the observations 
of Sanfelice and de Giaxa in the Bay of Naples. It was 
also found that sunshine affeded the number of ba<5leria 
at the surface. 

During the recent solar eclipse expedition to Vadso, we 
were able to extend these observations up to 71° N. lat.. 
Captain Eilertsen, of the Bergen Company's steamer 
Neptun kindly stopping the ship whilst we took the 
samples. The water for baderiological examination was 
colledted at about 2 feet from the surface in glass tubes 
(previously exhausted, sealed, and sterilised) by means of 
the apparatus devised by one of us and described in the 
Chem. News, Ixx., p. 54. The colonies were counted 
after about five days incubation at 20° C. 

Sample No. i : Vest Fjord, five miles from land, lat. 
68° N., at 6 a.m. Aug. 5, 1896; No. of colonies, mean of 
two cultivations, 51 per c.c. 

Sample No. 2 : Off Loppen, about three miles from 
land, lat. 70° 12' N., at 10 a.m. August 6, 1896. Unfor- 
tunately, the note of the number of colonies counted, in 
duplicate cultivations of this and of the following sample, 
has been lost ; but the average number in each case did 
not differ materially from that obtained from the Vest 
Fjord water. 

Sample No. 3 : Off the North Cape, about two miles 
from land, lat. 71° 10' N., temperature of sea 7-8° C, 
I a.m. August 7, 1896. A blank culture plate, similarly 
treated in every way, did not yield a single colony. 

No sample was taken in the Varanger Fjord on account 
of proximity to land and the towns of Vardo and Vadso. 
The temperature of the sea in the Fjord at 7 a.m. on 
August 8 off Vadso was 9*0° C. 

We have to apologise for this very fragmentary record of 
baderial life in the Ardlic Ocean, but we trust that it may 
have the effed of diredling the attention of ar(5tic and 
antariStic voyagers to the subjecft ; for, in view of the 
important relations existing between microbes and animal 
life in the ardtic regions, it is very desirable thut these 



Calcium Carbide — A New Reducing Agent. 



{Chemical Nbwb, 
Jan. 1, 1897. 



observations should be carried on up to higher latitudes, 
especially where the temperature of the sea does not rise 
above 0° C. 



ON THE SPECTRA OF COPPER, SILVER, 

AND GOLD.* 

By J. M. EDER and E. VALENIA. 

Our former preliminary research had shown that the ele- 
ments copper, silver, and gold give continually new results 
on the variable spedlra of the elements, for these elements 
yield spark- spedra extremely rich in lines for surpassing 
the corresponding arc-spedra in number and sharpness. 
These researches were commenced two years ago, but 
could not then be completed, as the spedlrograph with a 
quartz prism at the disposal of the authors had too slight 
a dispersion in the less refrangible regions, and the 
spectrograph with a compound glass prism supplied this 
deficiency in the blue and the violet as far as the begin- 
ning of the ultra-violet, but was not sufficiently eifeiS^ive 
in the visible part. 

We obtained two excellent Rowland's concave gratings 
with a very short focus, giving an admirable definition if 
the light was very strong. We seledled one which pro- 
duced the spedra of the first, second, and third order 
with great clearness. The spedra on both sides of the 
grating never show a pefedly equal brightness. 

The ultra-violet of the first order, of A = 3900, at about 
2500 is moderately bright, but from \ 2500 very faint. The 
spedrum of the second order is decidedly darker on the 
red, the yellow, and the green than the spedrum of the 
first order, which is in this region three times brighter 
than the latter. On the contrary, the brightness of the 
Bpedrum of the second order is very great. From A. 2800 
to A. 1900 we worked with the quartz spedrograph with 
one prism, which in these regions is far superior to the 
grating spedrograph in brightness and in resolving power. 
The spedrum of the third order is with our grating very 
bright ; in the ultra-violet of \ 2200 it is about equal in 
brightness to the ultra-violet of the second order, per- 
haps somewhat brighter. Consequently the spedrum of 
the second order is interseded by very luminous lines of 
the third order, which require to be separated out and 
identified, and then furnish an exceedingly sharp control 
for the measurements of the spedrum of the second 
order. The violet and ultra-violet near the Fraiinhofer 
line H come up so strongly in the spedrum of the third 
order as even to penetrate light yellow glass, and can be 
eliminated only by dark yellow glasses or concentrated 
strata of picric acid. The spedrum of the fourth order 
was plainly visible in the grating which we used, but its 
brightness is small. 

The authors reproduce an important illustration from 
Ames's memoir, " The Concave Grating in Theory and 
Pradice," taken from the yohns Hopkins University Cir- 
cular, No. 273, 1889. 

As a source of error in working with the grating- 
spedrograph are mentioned the so-called ghostly lines, 
which sometimes appear as rather sharp lines at almost 
equal distances, or sometimes as a unilateral expansion 
of very intense lines. 

1. The copper lines 5782, 5218, and 5105 correspond 

to the lowest temperature prevailing in the Bunsen 
fiame. 

2, The same lines with an accession of Cu ^ = 5700, 

5292, 5153, 4704, 4651, and 4275, pertain to the 
rather higher temperature of the faint sparks 
springing on between eledrodes saturated with 
copper chloride. 



• An especial reprint from the Transactions of the Mathematical 
and Natural Science Class 0/ the Imperial Academy oj Sciences, 
Vienna, 1896. 



3. All the lines occur in the arc-spedrum, and at the 

highest temperatures of the arc-spedrum, and 
must consequently be considered as constant lines 
peculiar to copper at the most variable temper- 
atures. 

4. In the arc-spedrum there occur far more lines than 

in the cases described under i and 2, which holds 
good especially for the more strongly refrangible 
lines. As especially charaderistic lines, in addition 
to those mentioned under i and 2, we mention 
A = 4o62, 3308, 3275, 3247, 2392. 

5. In the spark-spedrum all the main lines mentioned 

under i, 2, and 3 occur also as principal lines. In 
addition there appear many very intense new lines 
which are wanting in the arc- and the fiamC' 
spedra, whilst some strong Cu lines of the arc- 
spedra recede or disappear at the high temperature 
of the spark of the Leyden jar. 

As regards these phenomena, the Cu-spedrum must be 
regarded as very variable according to the temperature. 

Silver, even in the strongest Leyden jar spark, is less 
luminous than copper or gold. When the Ruhmkorff 
spark strikes over, the atmospheric lines come up very 
strongly, so that we were compelled to work in an atmo- 
sphere of hydrogen. But even in this case the subordi- 
nate rays of the Ag-spedrum were but feebly luminous. 
A number of the silver lines in the green part of the 
spedrum are extended into bands, but there are many 
sharp lines, and in the more refrangible part of the 
spedrum sharp lines predominate. 

The spedrum of silver must be considered as variable, 
since it becomes extremely rich in lines by the accession 
of intense silver lines in the hot Leyden spark. The 
moderately bright lines of the arc-spedrum are mostly 
retained, but are often surpassed in intensity and sharp- 
ness by the new lines of the spark-spedrum. 

The spedrum of gold is less known than the spedra of 
copper and silver. The lines of Lecoq, A = 56oi, 5230, 
5210, 4437, 4338, and 4064, do not belong to gold. 5601 
and 5210 belong to palladium, 5228 and 4442 to platinum, 
and 4355 to air (nitrogen). 

Kriiss was in error in ascribing the line 4064 (more 
corredly 4065) to nitrogen, since it appears distindly in 
an atmosphere of pure hydrogen. 

The authors have observed 660 lines in the spark- 
spedrum of gold, 50 of which are common to the spark 
and arc spedra, but more than 500 are new lines. 



CALCIUM CARBIDE: A NEW REDUCING 
AGENT. 

By H. N. WARREN, Principal, Liverpool Research Laboratory. 

Since the introdudion of this remarkable substance, it is 
significant that scientific men have been content to allow 
the produd to rank solely as a water decomposer, and 
thus regard the produdion of acetylene the only available 
produd. 

Researches of a somewhat lengthy description, which 
have lately been carried out at the above laboratory, in- 
volve the use of calcium carbide as a metallurgical 
reducing agent. 

In the first instance an excess of litharge was heated 
to redness in contad with the carbide, in a clay crucible, 
the readion being accompanied by vivid incandescence, 
resulting in the formation of metallic lead and calcium 
oxide, CaO. 

A further portion was now seleded, in which the pro- 
portion of carbide excelled that of the litharge ; this was 
further subdivided into various smaller portions, each 
portion being exposed to various temperatures, resulting 
in a regulus of calcium and lead of varying percentage, 
together with the expulsion of CO3. 



CHBUICAt NbWS) 1 

Jan. I, 1897. I 



Manufacture of Calcium Carbide. 



The alloys thus formed are all more or less brittle, and 
to a certain extent sonorous when struck, their melting- 
point ranking below that of pure lead, and are slowly, but 
completely, decomposed in contadl with aqueous vapour, 
the rea(5lion being much less energetic than that afforded 
by alloys of lead with the alkaline metals. Stannic 
oxide, cupric oxide, and also ferric oxide, at corresponding 
higher temperatures, were readily reduced, yielding re- 
sults of no pra&ical value ; in the case of the cupric 
alloys those samples containing under i per cent of cal- 
cium being rendered cold-short and breaking under very 
small strain, whilst, on the other hand, iron containing 
calcium approaches in appearance that of ferro-manga- 
nese, being even more brittle, and very oxidisable in con- 
tact with water. 

In a further operation, oxides of manganese, nickel, 
cobalt, and even chromium, molybdenum, and tungsten, 
were readily reduced, yielding calcium alloys. Results 
of experiments, comprising the redudlive a(5tion of the 
carbide upon the earthy chlorides and their haloids, will 
be shortly to hand. The already partial success of these 
readions seem to point most conclusively towards a new 
and powerful reducing agent, which at the same time, 
considering the market value of the carbide in question, 
could not fail to replace both sodium and potassium. 



Liverpool Research Laboratory, 
18, Albion Street, Everton, Liverpool. 



THE MANUFACTURE OF CALCIUM CARBIDE.* 
By J. T. MOREHEAD and G. de CHALMOT. 

So universal is the interest in acetylene gas and so dif- 
ferent the estimates and opinions as to the cost of calcium 
carbide as a source of the cheap produdlion of acetylene 
gas, that we have thought it desirable to place on record 
the data from our a(5tual experience in the produdtion of 
calcium carbide in quantities. The works of the Willson 
Aluminium Company have been running night and day 
since May ist, 1895, producing calcium carbide. These 
works are daily duplicating the results here given and can 
expand indefinitely. Each individual step, except water 
power, as taken at Spray, N. C, is capable of being 
changed in the dire(5lion of reducing the cost of the out- 
put, as these efforts have been attended with the clumsi- 
ness, lack of adaptability, and excessive cost that is 
incident to all efforts along an untrodden path. Still we 
can produce calcium carbide at less than 25 dols. per 
ton, including wear and tear and interest on capital. 

Beyond looking after the dynamos, no special training 
is necessary, as neither metallurgical nor chemical skill 
is required in the operations. We grind and mix coke 
and lime, start the water wheel, see that the arc is 
formed, shovel in the mixture of lime and coke, and the 
volt- and ammeter show when to lower or raise the car- 
bon pencils, which is done by means of a screw located in 
the dynamo room, away from the furnace. We can 
measure with an ordinary yard stick on this screw the 
height of the piece of carbide in the furnace. We stop 
when we have raised the carbon pencils 33 inches, switch 
the current off to another furnace and repeat the opera- 
tion. The carbide in the former furnace, as soon as 
cooled and brought in contact with water, is all ready to 
do perfed work in generating acetylene gas ; it will pro- 
ceed with this work without help and will make room 
therefor in spite even of bands of steel. 

Water power costs us 6 dols. per horse power. Water 
in the raceways ready for the water wheels is now offered 
in enormous quantities to the Willson Aluminium Com- 
pany at the rate of 5 dols. per horse power per year. 



* Read Sept. 3rd before the Springfield meeting of the A.A.A.S. by 
one of us (M). We have made since then several additions, so as to 
make the article complete up to the present time. From the Journal 
of the American Chemical Society, April, 1896. 



These powers are located at different places, where coke 
and lime can be had cheaply, and also cheap transporta* 
tion for the carbide to the market. 

The technical description of our process which follows 
herewith was written by G. de Chalmot, who has had for 
some time personal supervision of the operations of the 
Willson Aluminium Company. 

In the year 1888 Mr. T. L. Willson started a series of 
experiments with a view of reducing refradory ores in the 
eledric furnace, and among other valuable things he 
made calcium carbide.* 

We will first give a short description of the furnace 
and a general outline of the process, then enlarge some- 
what on the details. The furnace used in Spray, N. C, 
is built of ordinary brick (a sedtional front view is given 
in Fig. i). The front side is formed by four iron doors, 
the one above the other. The upper two remain closed 
usually. The chimney is attached near the top of the 
furnace, and commences with a flue, m, in the corner. 
The furnace measures at the bottom inside 2j by 3 feet. 
The eledric current enters at the bottom and top. The 
bottom eledrode is an iron plate, a, covered with 8 inches 
of carbon, b. For this covering we use pieces of carbon 
pencils or a mixture of coke and coal tar. Sixteen 
copper cables of 075 inch in diameter, c, convey the elec- 
tricity from the dynamos to the bottom eleftrode. 

Sixteen other cables are connedled with the top elec- 
trode, d. The top eleftrode is composed of six carbon 
pencils, e, each 4 inches square and 36 inches long. Six 
pencils are arranged in three pairs behind each other, and 
are cut out at the top so as to fit in the carbon holder,/. 
They are enveloped together by a sheet of iron, g-, which 
is shown in the right-handed furnace of Fig. 1. They 
really form one pencil. The carbon holder is screwed to 
a copper bar, h, which is three inches square, and to 
which the copper cables are connedted. This bar is fas- 
tened by a chain that runs over two pulleys to a long 
upright screw, i. On this screw is a nut which forms the 
centre of a wheel, k. By turning the wheel the screw can 
be raised or lowered. The man who attends to the wheel 
has the volt- and ammeter before him. The eledlric 
current is generated in two dynamos to which trans- 
formers are conneded, and which can give a current of 
from 50 to 100 volts. The power is furnished by a water 
wheel of 300 horse power under 28 feet fall. 

Two of the furnaces have been working for twelve 
months, and they have given satisfadion, except for work- 
ing not sufficiently economically. In the furnaces built 
for the Niagara Falls Carbide plant many changes which 
we suggested have been adopted, looking to economy of 
produdlion. We give here a short description of these 
furnaces (Figs. 2 and 3). 

In Spray it is necessary to allow the furnace to cool 
before emptying it. In order to use one and the same 
furnace continuously, the bottom of the furnace is re- 
placed by an iron car, a, which runs on a track, and in 
which carbide is formed. When the car is filled the pen- 
cils, b, have been lifted entirely out of it. The current is 
then shut off, door c is opened, the full car is run out and 
replaced by an empty car. The pencils are lowered 
again to the bottom of the car and a new run is com- 
menced. 

The bottom of the car is covered with from 4 to 8 
inches of carbon. When the contents of the car have 
sufficiently cooled outside the furnace, which will take 
from six to twelve hours, the body of the car is lifted from 
the track by the trunnions, d, and turned over. The con- 



* We will note here that Moissan, who discovered this process for 
making carbide, independently of Mr. Willson, communicated inci- 
dentally, at the meeting of the French Academy of December 12th, 
1892 [Compt. Rend., 115, 1033) that a carbide of calcium is formed if 
calcium oxide is heated in an eleftric furnace with carbon eledtrodes. 
He investigated the compound much later (Compt. Rend., 118, 50). 
Mr. Willson, who sent, during the summer of 1892, samples of 
carbide, for examination, to Lord Kelvin, of the Glasgow University, 
clearly antedates Moissan. See Journal of Franklin Institute of 
1895, page 333.— Note. 



Manufacture of Calcium Carbide, 



5 Crbuical Nbws, 
I Jan. I, 1897. 




Fig. I. 

time at one point, for which the arc has always a great 
tendency. This will materially increase the efficient use 
of the heat of the arc. Under the track of the car is the 
bin, h, in which the unreduced material is colledted that 
will fall from the car when this is taken out. This mate- 
rial can from time to time be taken out through the door i. 
The carbon holder is more complicated than in the Spray 
furnace. Twelve carbons are used, and the holder is 
therefore about twice as heavy. It is not advisable to 
suspend this carbon holder from a copper bar, which 
moreover becomes rather hot in this closed furnace. 
The carbon holder is therefore attached to a rod, /, which 
is composed of three slabs. The inner one is of copper, 
and measures 6 by ij inches, and the outer ones are of 
iron and are 6 inches by i. Since it is not pradical to 
attach the twelve carbons in their iron casing to the car- 
bon holder in the furnace, the holder itself is composed of 
two pieces, m and «, which slide into each other. The 
aggregate of pencils is connedted to piece n outside the 
furnace, and the whole is placed in the car a. Rod / is 
so far lowered that piece m will easily slide into piece «, 
and the connexion can easily be effedled. Iron plates, 0, 1 



tents are dropped on a grate formed of iron bars, on which 
the piece of carbide remains, while the unreduced material 
falls through into a lower room, where it is colledted to be 
used again for the formation of carbide. The mixture of 
lime and coke is fed into the car through the flues, e, 
which extend along the whole length of the car. The 
rods,/, which bear four blades, extend through the whole 
breadth of the feeding flues. These rods are turned auto- 
matically, and the faster they turn the more material is 
fed into the car. In order to stoke the furnace automati- 
cally, the car is attached to an iron bar, g', by two hangers 
and a coupling in front of the car. Bar g extends through 
the back wall of the furnace, and is automatically moved 
forward and backward for about 2 inches and about 
twenty times per minute. The car is thus also rolled 
backward and forward on the track for about 2 inches 
each time. Every time that the car stops or starts it gets 
a little jerk which is sufficient to fill up the holes made by 
the escaping gases in the loose material. This motion of 
the car further prevents the arc being located for a longer 



M 




'/y//////,y/A 






■■///////,'/A 




Chbhical Nbws, I 
Jan. 1, 1897. I 



Quantitative Analysis of Spectra, 



are placed between the carbon holder proper and the 
pencils. These plates, 0, are about i inch thick. They 
are fastened to the inside of the carbon holder by pins 
which are inserted in the holder, and fit in holes of the 
plates. These plates can be easily removed and replaced. 
It will sometimes happen that a small arc is started be- 
tween the pencils and the inside of the carbon holder, 
and a part of the carbon holder will melt. In the case 
that the plates are used one can simply replace these 
plates. The car a forms one of the eledrodes, and is 
conne(5led with the bottom cables, q, by two clamps, p. 
The lower clamp is stationary and the upper one can be 
opened. The clamps are tightened around the appendage 
z of the car by a wedge and screw, 5. When the clamps 
are fastened the slide t is lowered so as to shut the open- 
ing. The eleftric connexion with the car can also be 
and is better made through the bar ^, which in that case 
is composed of an iron and a copper slab. It may also be 
made by two copper bars which run alongside of the car 
and are pressed against it with springs. The furnace is 
entirely closed. When it is started the door c is shut, 
but the door u is kept open till the carbon monoxide, 
which is formed in the readlion, has replaced the air in 
the furnace. This point is reached when the flame 
comes out of this door. Door u is then also closed and 
the gases escape through the chimney, v. The use of 
door M prevents explosions of the carbon monoxide in 
the closed furnace. Chimney v begins just over the car 
The carbon holder and the rod I are therefore not in' 
the current of the hot gases. The upper part of the 
furnace is cooled moreover by an air jacket, w, through 
which a draught of air is maintained. The cold air 
enters through openings x and the warm air is led ofT by 
chimney >». The warm air may be utilised for heating 
the building. The chimney gases pass through flues or 
rooms, in which the lime dust is collected by proper 
means. Owing to valuable suggestions of our super- 
intendent, Mr. J. C. King, this furnace is called the King 
Furnace. Besides these two types of furnaces, several 
others have been proposed. 

In order to start our present furnace, we shut the 
lower iron door and lower the pencils to the bottom of 
the furnace. The current is turned on and the mixture 
of coke and lime fed in, the arc being kept covered 
with the mixture as high as one foot around the pencils. 
It is then easier to keep the arc steady. It is neces- 
sary to stoke from time to time, for the gases which 
are formed in the arc constantly make channels through 
the material, and especially if unslacked lime is used. 
These channels will not fall in, and less material will 
come into the arc. The feeding in of the material is 
continued for several hours. If the attendant at the 
hand wheel sees that the voltage becomes low, he raises 
the pencils. If the arc should be broken the amperage 
becomes zero and the voltage high, and in that case the 
pencils are quickly lowered. After shutting off the 
current it is well to allow the furnace to cool two or 
three hours before emptying it. 

(To be continued). 



QUANTITATIVE ANALYSIS OF SPECTRA. 

A NEW method has been elaborated by G. and H. Kriiss, 
and is now published by H. Kriiss after the death of G. 
Kriiss {Zeit. Analyt. Chemie). 

If a substance in a layer of a substance, of a thick- 
ness = I, enfeebles by absorption the light which it 
transmits from the intensity — 

I toil 
n 

(and has therefore the enfeebling fador K for the stra- 



tum I), the intensity I' of the light passing through a 
stratum of the thickness m will be — 



(I) 



r = 



(This applies stridlly for monochromatic light with only 
one fadtor of enfeeblement). 

If we assume the original strength of the light = i, 
we obtain the equation — 



(2) 



I'=_L. 
n m 



Therefore log. « = - '°g- ^' . 
in 

Ir we call e the coefificient of extin(5lion of the sub- 
stance concerned,— that is, the reciprocal value of the 
thickness of the stratum which is necessary to reduce 
the transmitted light to jV'h of >ts original intensity,— 
then when — 

»t « i r will = T»(,. 
e 

Hence follows log. n = e, or also — 



(3) 



_ log. I' 



m 



If we work with the stratum m = i we have— 
(4) .. « = log. I'. 

The coefficient of extinftion is hence equal to the 
negative logarithm of the residual brightness. When 
this has been determined for the stratum = i it may be 
taken diredly from the proper tables. 

The authors justly point out that to many the process 
is rendered less intelligible by the circumstance that We 
do not measure the thickness of the stratum at which the 
brightness is reduced down to ^^, but in its stead that 
effedled by a constant depth of stratum which is of 
different thickness for each body. 

In order to draw a conclusion as to the concentration 
of a solution from its coefficient of extindtion as thus 
determined, we must consider that the reduction of 
brightness depends only on the quantity of the absorbent 
substance present in a given depth of the solution, so 
that a greater concentration of the liquid at the same 
depth must have the same effecft as the introdudlion of 
a corresponding deeper stratum of a solution of an un- 
changed concentration. Hence it follows that the ratio 
of the concentration, c, to the coefficient of extincflion, e, 
for each absorbent substance, is a constant which must 
depend on the kind of the substance. It is known as the 
absorbed proportion — 

(5) .. A=£, 
e 

whence, if A is known, the concentration follows from 
the measurement of e. 



(6) 



c = A. ^. 



The authors, in order to obviate the above difficulty, 
have modified the procedure, so that the depth of the 
stratum, w, which occasions a certain redudlion of bright- 
ness, is really measured- 

If the intensity, I, of the light, is reduced to I' by a 
stratum, wi, of a solution of the concentration, c, whilst 
a stratum of the thickness i of a solution of the same 
substance of the concentration i reduces the light to 

— , we have — 



(7) 



If we put — 



I' = 



X 



Isomerism in the Pyrazol Series. 



iCrbuical Mbws. 
\ Jan. 1, 1807. 



then follows x =i x = n m c, ot log. « = w c, log. n. 



without succeeding in exadlly ascertaining the experi- 
mental conditions favourable to the formation of either 



(8) 



m log. n 

», the specific power of absorbing light, is for each 
substance a constant ; accordingly also log. «i respefting 
its reciprocal value, we call k. Thus we have — 



(9) 



c^i. 



This magnitude k is nothing better than the absorptive 
ra^io A as above reduced, for we had above c = A. c, and 
we have here further (if »« is selefted so that x = lo),— 



whence there follows — 



X 

m 
m 



The apparatus used by the authors cannot be intelli- 
gibly described without the accompanying figure. 

In using the apparatus we pour into one of the vertical 
tubes the solvent liquid, and into the other the liquid to 
be examined, and we allow the light from a Hiibner 
refleAing prism to fall upon a spedtro-photometer, so ad- 
justed that, with equal illumination, one-half of the field 
of vision has only one-tenth the brightness of the other 
half.— Zeit. Analyt. Chemie. 



CASES OF ISOMERISM IN THE PYRAZOL 

SERIES. 

By R. VON ROTHENBURG. 

I. The Question of the Constitution of the {c)-Phenyl- 
pyrazol Series. 
I HAVE mentioned in the Berichte (xxvii., 789) that I have 
obtained Buchner's phenylpyrazol, melting at 228', along 
with other more fusible produdls, by the aftion of hydrazin 
hydrate upon benzaldehyd, 

Knorr, by the reciprocal adlion of the same substances, 
has obtained merely phenylpyrazol, melting at 78°. He 
believes, on the basis of theoretical speculations, that the 
phenylpyrazol melting at 228° must be (4)-phenyipyrazol, 
and hence declares my statement as " puzzling." 

Recently, Buchner has contradided the views of Knorr, 
and shown that neither his theoretical expositions nor 
their experimental proofs are in all respects trustworthy. 

Before anew taking part in the discussion, it seems 
advisable to describe accurately the experiment which I 
formerly instituted. 

Crude benzoylaldehyd — obtained in the ordinary 
manner — was mixed with i mol. hydrazin hydrate in an 
alcoholic solution, producing a violent reaftion. The 
mixture was then heated for some time in the water-bath, 
poured into several times its volume of water, the oil was 
taken up in benzene, separated from the water, and the 
basic constituents were withdrawn from the oil by means 
of dilute hydrochloric acid. The solution thus obtained 
yielded the platinum salt which I have described {loo. 
cit.), and after neutralising with soda a crystalline mass 
which, on fradtional crystallisation, yielded first slightly 
yellowish crystals melting at 228°, and subsequently frac- 
tions fusible below 100°, which I have already described 
as an isomer. The yield of produa fusible at 228° was 
about 10 per cent of the amount to be theoretically ex- 
peiSted. 

That both phenylpyrazols (melting-points 228*^ and 78°) 
should be obtainable from benzaldehyd does not agree 
with Knorr's theory of the pyrazol nucleus, but it does not 
clash with the behaviour of phenylhydrazin with benzoyl- 
aldehyd ; the less so, as both pyrazolswere also obtained 
by means of diazoacetic ester, and in various proportions, 



isomer. 

In spite of the brilliant experimental researches of 
Knorr on the pyrazols, which showed the formation of 
only one methylpyrazol from oxymethylenaceton, which 
allowed the same methylpyrazol to be obtained from two 
isomers of the phenol series, and in spite of the produc- 
tion of a (3, 4, 4, 5)-tetramethylpyrazol, no unobjedtionable 
proof has been furnished that also (3)- and (5)-phenyl- 
pyrazol must be identical, since it is evident that the 
methyl and the phenyl-group must have a very different 
influence. 

(5)-Phenylpyrazol, or pyrazol (5). carbonic acid, must 
be obtainable by the oxidation of the (5)-phenyIpyrazolin 
obtained by me from cinnamelydenazin. May I, since I 
cannot at present execute these experiments, address to 
Dr. Buchner the request that he would include these in- 
vestigations within the scope of the oxidations which 
he has in view ? 

Buchner has pointed out that a resorcin fusion performed 
at too high a temperature is no proof for the presence of 
an o-dicarbonic acid ; since resorcin alone, if heated for 
a long time at a sufficiently high temperature, or in pre- 
sence of a condensation agent, yields strongly fluorescent 
melts. Knorr has totally overlooked this fadl. 

Buchner's resorcin fusion at a sufficiently low tem- 
perature, and my synthesis of hydrazin hydrate, require 
imperatively that phenylpyrazol (228°) must not be re- 
garded as (3)- or (5) -phenylpyrazol. 

If Knorr does not view Buchner's or my statements 
as founded on air, he must admit that phenylpyrazol 
(228°) cannot be (4)-phenyIpyrazol. 

2. On the Synthesis of Antipyrine. 
About a year ago I described {Berichte, xxvi., 2974) a 
method for obtaining a phenylpyrazolon (melting-point 
155°), previously obtained by different methods, and I 
assigned it the constitution — 

n:=z:ch 

I I 
C6H5N CH2 

CO 

On the contrary, F. Stolz advocated the formula — 
C6H5N CH 

II II 
HN CH 

\/ 

CO 

He grounded his opinion essentially upon the circum- 
stance that the isomeric phenylpyrazolon melting at n8° 
must have the formula which I assumed for the phenyl- 
pyrazolon melting at 155°, since it is formed from oxal- 
acetic ester hydrazon. I did not then touch upon this 
point, as the produdlion of phenylpyrazolon melting at 
118° from oxalacetic ester hydrazon takes place in a 
manner which admits of no inference as to its constitu- 
tion. On the other hand, formalacetic ester forms with 
phenylhydrazin not the phenylpyrazolon fusible at n8°, 
but that melting at 155°. 

Stolz certainly contests that this pyrazolon can here 
come into consideration, but he has not found it neces- 
sary in any manner to establish his opinion. Why, lastly, 
has he not obtained (i)-phenylpyrazolon from oxalacetic 
ester and phenylhydrazin in the same manner in which I 
obtained pyrazolon itself by means of hydrazin hydrate ? 

In the meantime there have appeared memoirs and 
patent specifications which induce me to oppose energeti- 
cally the constitutional formula of Stolz as entirely 
untenable. 

If, as Stolz assumes, phenylpyrazolon fusible at 118° 
were really the lower homologue of Knorr's (i)-phenyl. 
(3)-methylpyrazolon fusible at 127°, both would be 



Substituted Glycolic Esters and Glycolhydrazid, 



OHBMicAL News, I 
Jan. 1, 1897. f 

obtainable in an analogous manner by the circuitous way 
of phenylethoxylpyrazol ; but this is not the case. 

Whilst the hydrazones of the /3-ketonic esters when 
heated alone pass into normal pyrazolones, with abscis- 
sion of alcohol, they are converted by acid conJensation 
agents into alkyloxypyrazols, and by concentrated sul- 
phuric acid into indol-derivatives. 

It seems to me free from doubt that the formation of 
indol, and that of the alkyloxypyrazols, occasionally occur 
colledively, and the non-symmetric hydrazines formed 
split off ammonia or water. 

It is not surprising that in an acid solution the more 
basic pyrazol is formed rather than the very feebly basic 
pyrazolon. It can be explained only under these supposi- 
tions, that we do not obtain from acetacetic ester pyra- 
zolon Knorr's pyrazolon fusible at 127°. 

From the (i)-phenylpyrazolon-(3)-carbonic ester the 
Hochst Colour Works obtain (i)-phenyl-(2) methyliso- 
pyrazolon of the melting-point 117°. 

From Walker's (i)-phenylethoxylpyrazol there is cer- 
tainly also formed a phenylmethylisopyrazolon fusible at 
117°, but it must be (2)-phenyl-(i)-methylisopyrazolon, 
which melts at about the same temperature. The 
melting-points of the (i, 2)- and (2, i)-isomers are so 
near together that they cannot be used for charaderising 
and distindtion. 

Knorr's pyrazolon (127°), as already remarked, is dif- 
ferent from the " phenylmethoxypyrazol " obtained on 
treating the phenylhydrazon of a(5tetacetic ester with acid 
condensing agents and saponifying the alkyloxypyrazol. 
Consequently, their lower homologues may be different. 
The pyrazolon derivative, — 

C6H5N CCH3 

I II 

CH3N CH , 

\/ 

CO 

must be pseudoantipyrin. 

The halogen-cretonic acid, produced according to the 
German patent No. 64444, 's pseudoantipyrin, as Krauth 
has shown. This question is of no little scientific interest, 
since the antipyrins of the type — 

RiN CR2 

I II 

CfiHeN CH 

\/ 
CO 

are antipyretic medicines, whilst those of the type — 

C6I-I5N CR2 

I II 
RiN CH 

\/ 

CO 

are poisons. 

As appears from the above explanations, the elabora- 
tion of the pyrazolon region carried out by Stolz and the 
Hochst Colour Works is, from a scientific point of view, 
not unobjedionable. 

The German Patent No. 66808 declares it possible to 
obtain pyrazolon derivatives by the oxidation of /3-amido- 
crotonicanilidon, which is known to be impossible. 

Finally, the Hochst Colour Works have not been able 
to refrain from announcing the notorious antipyrin alcohol 
for a patent, on January 5, 1892. 

3. On the Pyrazolon-iulpho Acids. 

C. Walker recently describes some sulpho-acids of the 
pyrazolons which he has obtained by means of concen- 
trated sulphuric acid from the hydrazones of substituted 
acetacetic esters. To these sulpho-acids he ascribes a 
peculiar and at least improbable constitution. 

Walker's formulae prove anew to what improbable 
assumptions the obstinate adherence of Neff and his 



school to the oxycrotonic formula of acetacetic ester and 
the isoconstitution of the normal pyrazolons must lead. 

4. On the Isomeric Benzoylphenylmethylpyrazolons. 
Neff believes, as is well known, that he has demonstrated 
for (i)-phenyl-(3)-methylpyrazolon (fusible at 127°) the 
formula — 

HN C.CH, 

I II 
C6H5N CH 

CO 

because he has succeeded in producing two isomeric 
monobenzoyl-derivatives. The proof has, however, been 
in no respedt supplied. He overlooks that all the other 
readions of this pyrazolon fusible at 127° can be much 
more easily explained by the formula — 



N: 



-CCH, 



CeHjN CHa . 

\/ 
CO 

How will he explain the solubility of the pyrazolons and 
the insolubility of antipyrin in alkali by means of his 
formulae ? — Journal fur Praktische Chemie, New Series, 
vol. li., p. 157. 



ON SUBSTITUTED GLYCOLIC ESTERS AND 

GLYCOLHYDRAZID. 

By TH. CURTIUS and A. SCHWAN. 

This paper forms the fifth part of a prolonged account 
of the hydrazides and azides of organic acids, appearing 
under the name of Th. Curtius. 

Some years ago one of the present writers found that if 
benzoylglycolic ester is exposed to the adlion of 2 mols. 
diammonium hydrate benzhydrazid and amidoglycocoll 
are produced with abscission of water and alcohol. 

This remarkable readion yielded the first representa- 
tives of two classes of organic substances hitherto 
unknown, the primary acidylhydrazides and the hydrazin 
acids. 

As subsequent researches had shown that primary 
acidylhydrazides are quite generally formed by the a(5tion 
of hydrazin hydrate upon acid esters, we might have 
expeifted that benzoylglycolic ester with i mol. hydrazin 
hydrate would yield benzoylglycol hydrazid. The latter 
would then be resolved by the adion of a second mol. of 
the base into benzhydrazid and glycolhydrazid. 

One of the authors had previously expressed the view 
that the last-named substance would correspond to the 
constitutional formula NHzNH'CHa'COOH, and that 
therefore, in addition to benzhydrazid, there would appear 
hydrazinacetic acid or amidoglycocoll on the scission of 
benzoylglycolic ester. 

We have established that our view here given is correA, 
and that the substance in question is the hydrazid of 
glycolic acid, CHaCOH^CONHNHz. 

In the adlion of alcohols or acids upon diazoacetic ester 
one of us has found a method for producing substituted 
glycolic esters of any kind. By means of this process we 
have obtained a series of such bodies, hippurylglycolic 
ester, oxalylglycuric ester, succinylglycolic ester, benzyl- 
glycolic ester, and glycolic ester. 

The organic acids readt in some cases explosively upon 
diazoacetic ester even in the cold, especially oxalic acid. 
With other acids the readlion occurs only in heat, but 
then very energetically. 

Pure water or alcohol readls only with extreme diffi- 
culty upon perfe(5tly pure diazoacetic ester, so that it has 



8 



Derivatives of Columbium and Tantalum. 



( Chemical News, 
1 Tan. 1, 1897, 



not been pradicable thus to obtain a good yield of glycol 
esters. 

As for the effeds of hydrazin hydrate upon these esters 
the rea(aion might either take place as with ordinary 
esters, so that glycolhydrazides are produced in which 
the hydrogen of the hydroxyl group is substituted by an 
alkyl or acidyl group, or — as the substituted glycolic 
esters might be regarded as double esters — there might 
readt simultaneously, the one attacking the esterified 
carboxyl group, and the other the etherified hydroxyl 
group. 

Investigation has shown that upon alkylglycolic esters 
there readts only one mol. of hydrazin hydrate, forming 
alkylglycol hydrazid and splitting off alcohol, whilst in 
the acidyl-glycolic esters there always reacft two mols. of 
hydrazin hydrate. 

As for the constitution of the so-called hydrazin-acetic 
acid we have to consider firstly its formation from glycolic 
ester. Hydrazin hydrate adts violently upon this sub- 
stance even in the cold. On evaporation there remains 
hydrazid in massive crystals. But if in place of glycolic 
acid we employ alkylised glycolic acids, then if the sub- 
stance in question is to be regarded as hydrazin acetic 
acid, hydrazin acetic acid should also be formed with 
abscission of alcohol, instead of which we always obtain 
alkylised glycol-hydrazid. 

Finally, the remarkable instability of the so-called 
amidoglycocoll in an aqueous solution as against dilute 
mineral acids, compels us to regard the compound as 
glycolhydrazid. 

The authors then describe the preparation and properties 
of glycolic ester, of phenylglycolic ester, of benzylglycolic 
ester [C11H14O3] , of ethylglycolic ester, hipperylglycolic 
ester [CiiHi303N],oxalylglycolic ethyl ester [C10H14O8], 
Buccinylglycolic ester [CizHisOs]. 

The authors next study the adion of hydrazin hydrate 
on the substituted glycolic esters. 



DETERMINATION OF PHOSPHORUS IN 
ASH OF COAL AND COKE. 
By LOUIS CAMPREDON. 



THE 



The proportion of phosphorus in the ash of coal or of 
coke yielded on carbonisation is particularly important, 
when the fuel is cast into the blast-furnace, for the manu- 
failure of fine castings in which the percentage of phos- 
phorus has to be as low as possible. In faft, all the 
phosphorus introduced into the melted mass with the ash 
of the reduftive combustible enters into the metal. 

Procedures Followed. 

All authorites agree in advising the determination of 
the phosphorus in the ash given by the combustible when 
burning, and not in the combustible itself. The opinion 
of various authors concerning the mode of attacking the 
ash, so as to dissolve the phosphorus contained, differs 
slightly. 

The attack with hydrochloric acid is recommended by 
Fresenius, by Post, and Munck. The last mentioned 
adds : " There is no reason to fear that in this primitive 
treatment iron phosphate may remain undissolved. In 
the experiments made on this point the contrary has 
always resulted ; even the residue appeared very rich in 
iron." 

On the other hand, Blair, Baron Juptner von Jonstorff, 
as well as Arnold, recommend the fusion of the ash as 
the preferable if not the only method. 

Comparative Trials. 

I have made numerous comparative trials on the ash 
of coals from English sources, proceeding as follows : — 

I. Attack with Hydrochloric Acid.— I treated o-6oo 
grm. and i"200 grm. of ash very finely powdered in a 



pear-shaped phial, covered with a watch glass with 30 to 
40 c.c. of strong hydrochloric acid. A heat of 80 — 100° 
was applied by means of the water-bath or the sand- 
bath for fifteen to twenty hours. It was evaporated to 
dryness to render the silica insoluble; it was then taken 
up with a few c.c. of aqua-regia composed of equal 
volumes of nitric and hydrochloric acid. Heat was 
applied, and there were further added 5 c.c. of nitric acid 
to expel the hydrochloric acid. Lastly, it was diluted 
with cold water, and the whole poured into a flask 
graduated from 60 to 120 c.c. The volume is made up 
and the whole filtered through a dry filter-paper. We 
take 50 or 100 c.c. of the liquid (corresponding to 0.5 or 
I grm. of the substance), neutralise with ammonia, 
acidify slightly with nitric acid, heat to 60° in a small 
pear-shaped flask, and effedt the precipitation by adding 
20 to 30 c c. of molybdic solution. Allow the mixture to 
settle for two to three hours at 30 to 40° C, filter the 
phosphomolybdic precipitate through a double tared 
filter ; wash with water acidulated with nitric acid (40 c.c. 
acid per litre) ; dry the filter at 105° and weigh. 

The weight of the phosphomolybdate multiplied by 
o'oi63 gives the weight of the phosphorus. 

2. Fusion with Alkaline Carbonates. — Melt o*6oo grm. 
coal with 3 grms. of a mixture of equal weights sodium 
and potassium carbonates, and keep it in a state of fusion 
in a platinum crucible for ten to fifteen minutes. When 
cold the mass is taken up in water acidulated with hydro- 
chloric acid. The liquid is poured into a porcelain 
capsule, adding then an excess of hydrochloric acid, and 
evaporating to dryness. The process is continued as in 
the first method. 

To obtain accurate results it is necessary to fuse with 
alkaline carbonates and precipitate with molybdic solution 
according to the diredtions of the present paper. — Comptes 
Rendtts, cxxiii., No. 23. 



DERIVATIVES OF COLUMBIUM 
TANTALUM.* 
By MARY ENGLE PENNINGTON. 



AND 



Among the more metallic members of Group V. of the 
Periodic system are the elements columbium and tanta* 
lum, which, though almost a century old and counting 
among their devotees such investigators as Rose, Her- 
mann, Marignac, Rammelsberg, and others of equal fame, 
still offer many interesting problems to the student of 
inorganic chemistry. Comparatively few of the com- 
pounds of these elements have been prepared. Those 
which have been studied narrowly enough to afford an 
accurate knowledge of their chemical behaviour form a 
much shorter list. The early literature is, in many 
instances, very contradidlory, due to the supposed exist- 
ence of such elements as pelopium and ilmenium, 
engendering as they did the fruitful controversy between 
Hermann and Marignac, which controversy resulted in 
the tacit acceptance by the chemical world of Marignac's 
statement, that columbium is elementary. The old 
doubt, however, appears to have been revived through 
the very careful work of Kriiss in 1887, on the oxides of 
these metals, their separation from each other and also 
from the oxides which accompany them in their apparent 
minerals. 

He found through the fradtional crystallisation of the 
double fluoride of columbium and potassium, and by 
determining the atomic value of the various fradtions, 
that something apparently contaminated the columbium. 
In some fradlions the values obtained were far too low. 
This he accounted for by proving the presence of titanium. 



* From the author's thesis presented to the University of Penn- 
sylvania for the degree of th.D,, 1895. From the Joitrn. Amer. 
Chem. Soc, xviii., January, 1896. 



Cbruical News, i 
Jan. 1, 1897. I 



Derivatives of Columbium and Tantalum, 



Other portions, however, were much too high, and this, 
it was csrefully proved, was not due to adhering tantalum. 
Just what the substance was which gave in one fraction 
an Rv having almost double the accepted atomic mass 
was left undecided. 

A careful consideration of this question in the light of 
the various researches, makes it seem not improbable 
that the compounds of columbium, as we know them, are 
not perfedly free from contaminating substances. The 
many difficulties encountered in the separation of this 
oxide from others usually occurring with it, and the 
insufficiency of the prevailing methods of separation, 
seem to demand a more exa(5t knowledge of the behaviour 
of the element in the purest condition obtainable, and 
also when mixed with the oxides of tantalum and titanium 
which usually adhere to it. 

It was with the hope that some additional light might 
be thrown upon the general deportment of the derivatives 
of these elements that this research was undertaken. 

The material used was obtained from a columbite from 
Wakefield, N.H. An abundant supply of the mineral 
was secured through the kindness of Prof. S. P. Sharpies, 
of Boston, in whose possession it had been for some 
years, though it had never been analysed. Wakefield is 
a new locality for columbite. The deposit was discovered 
while mining for felspar. Near the columbite is quite a 
deposit of beryl. 

Analysis of Wakefield Columbite, 

The mineral occurs in large black lustreless masses- 
Scattered over the surface are little patches of a brigh* 
yellow substance. These proved to be uran-ochre, and 
gave evidence of the presence of the uranium which was 
later found in the mineral. Felspar occasionally 
penetrated the mass, though in small quantity. The 
specific gravity of picked material was found to be 5*662 
at 4° C. 

Decomposition was efJ'etSed by the method usually 
employed for this class of minerals. 

Fusion with. Acid Potassium Sulphate. — The finely 
divided mineral was allowed to stand over calcium 
chloride for some hours. The desired amount of this 
dry, and almost impalpable, powder was weighed off and 
mixed with at least nine times its weight of fused potas- 
sium bisulphate. This must be an intimate mixture. 
Great care should be exercised when the heat is first 
applied, else loss by spattering will occur. Frequent 
stirring tends to prevent this, and also hastens the 
decomposition. 

Some trouble was experienced by the fusion " climbing," 
and leaving far up on the sides of the crucible particles 
of mineral which could neither be driven down by heat or 
forced down by a platinum rod. To colledt these particles 
the crucible containing the clear quiet fusion was slightly 
tilted and the adhering portions covered with a little 
bisulphate. Then by gently heating the whole mass was 
driven down until it met the main portion of the fusion. 
All decompositions by this method were made in a large 
platinum crucible or platinum dish. The latter was pre- 
ferred. If the mineral is fine enough the fusion is com- 
plete in about five hours. 

The fused mass was taken up in a large quantity of 
water, and boiled out with water several times. The 
insoluble portion consisted of the oxides of columbium, 
tantalum, titanium, tin, tungsten, and any silica which 
was present. Small quantities of these oxides invariably 
remained dissolved, although the solution was boiled for a 
long time; it is, therefore, advisable to let the filtrate 
stand twenty-four hours, then re-filter. 

The moist oxides, according to Headden {Amer. your. 
Sci., xli., 91, 1891), should "be digested with yellow 
ammonium sulphide " to remove all tin, tungsten, &c. 
Rose recommends that yellow ammonium sulphide should 
be simply poured over them, and that this solution should 
be evaporated to dryness and gently ignited, to render 
the columbium and tantalum oxides which have been 



dissolved by the alkali, insoluble. Wohler (" Mineral 
Analyze," p. 140) claims that it is sufficient to treat the 
metallic oxides upon the filter with yellow ammonium 
sulphide. As some uncertainty existed as to the best 
course to pursue, the effetfl of ammonium sulphide when 
mixed with these oxides for a longer or shorter period of 
time was studied. 

Heating in a porcelain dish on the water-bath for 
three hours gave i'i5 per cent of the mixed oxides ; one 
and one half days, i*6o per cent; three days, 1*85 per 
cent; one week, 2*24 per cent. By pouring the sulphide 
over the oxides on the filter, as Rose and Wohler advise, 
0*24 per cent of the mixed oxides was obtained. 

Apparently, the moist metallic oxides are more readily 
dissolved by ammonium sulphide than is generally sup- 
posed, and, therefore, when working with columbites 
containing the acid oxides, care must be taken, or a very 
appreciable error may result. 

The ammonium sulphide solution was precipitated by 
dilute hydrochloric acid, and the precipitate was filtered, 
and washed with hydrogen sulphide water, alcohol, ether, 
carbon disulphide and ether. The mixed sulphides were 
carefully heated in the air, then reduced in a current of 
hydrogen gas. The residue treated with dilute hydro- 
chloric acid gave tin in solution, and left undissolved a 
small quantity of a black compound which proved to be 
the tetroxide, Cb204, with possibly a little tantalum. 

The moist oxides when treated with ammonium sul- 
phide have not only the acids removed, but the iron con- 
tained in them is changed to sulphide. This is dissolved 
out by dilute sulphuric acid. Filter off the oxides and 
wash them thoroughly with boiling water. A pump is 
usually necesssary because of the precipitate being finely 
divided, and having a tendency to clog the pores of the 
filter. By this treatment the oxides should be entirely 
freed from iron and manganese. Nevertheless ignition 
gave a powder having a distindl pinkish yellow hue, 
showing the presence of these elements. The oxides 
were, therefore, re-fused with potassium bisulphate and 
treated as before. The second fusion gave a produA 
lighter in colour, yet not perfedlly white. Another fusion 
was resorted to, and no loss in weight was observed, as a 
small amount of iron still adhered to the oxides. In (&& 
a. perfectly white mixture of the oxides has not been ob- 
tained by this method. 

The sulphuric acid solution of the iron which remained 
with the insoluble oxides was added to the aqueous ex- 
tradion of the fusion. This solution now contained iron, 
manganese, uranium, and calcium, with a large excess of 
sulphuric acid and alkali salt. Yttrium, cerium, and cal- 
cium were looked for according to the plan presented in 
Rose's " Handbuch der Analytischen Chemie," ii., 335, 
which is, in brief, this : — The greater part of the free acid 
is neutralised with sodium carbonate ; sodium acetate is 
added, so that acetic acid is in large excess. The earths 
are precipitated by ammonium oxalate, the precipitate 
being allowed to stand twenty-four hours. From 3 grms. 
of mineral only a very small amount was obtained. This 
was too small a quantity to investigate further, so that if 
any rare earths are present in the mineral they exist in 
traces. 

To the filtrate which contained iron, manganese, and 
uranium, were added ammonium sulphide and ammonium 
carbonate. The iron and manganese were precipitated 
as sulphides, while uranium was held back by the ammo- 
nium carbonate. Beryllium, if present, would have been 
found here. This element was sought for, since the 
locality from which the mineral came made it a probable 
constituent, but none was deteded. The sulphides 
having been filtered out, the filtrate was made acid with 
hydrochloric acid, the carbon dioxide boiled off, then the 
uranium precipitated by ammonium hydroxide. The 
uranium hydrate was filtered, washed, ignited, and 
weighed as U3O8. The sulphides of iron and manganese 
were dissolved off the filter in hydrochloric acid, oxidised, 
and separated by the basic acetate method, the man- 



10 



Problems of the Natural Sciences. 



CsbmicalNbws 
Jan. I, 1807. 



ganese being finally weighed as manganese pyro- 
phosphate. 

The water contained in this columbite was determined 
by heating in a boat in a glass tube, and colleding the 
aqueous vapour in a weighed calcium chloride U-tube. 

In the literature relating to columbites and allied 
minerals, while a ferrous content is given, the method by 
which it was determined is omitted. Perhaps this is due 
to the fadt that the customary decomposition with sul- 
phuric acid in a sealed tube naturally suggests itself, yet 
in applying this course to the columbite under examina- 
tion unexpefted difificulties were encountered. The 
experience is at least interesting. 

To be continued). 



NOTICES OF BOOKS. 



Oh certain Main Pyoblems of the Natural Sciences, and in 
particular on (I.) The Mechanical Processes which lie at 
the Foundation of the Electrical Phenomena. A Discourse 
by Dr. Anton K. Grunwald, Extraordinary Professor 
of Mathematics at the Imperial and Royal Technical 
High School of Prague. Delivered at the Annual 
Meeting of the Royal Bohemian Society of Sciences, 
January 31st, 1895. Prague : Published by the Royal 
Bohemian Society of Sciences. (" Ueber gewisse 
Haupt aufgalben der Naturwissenschaften, und zwor 
(I.) Ueber die Mechan Vorgange welche den Eledtr. 
zu Grunde liegen "). 

Professor Grunwald is already most favourably known 
to British physicists for his mathematical investigations 
on spedlroscopic phenomena. We find him now taking 
up a much wider question. In his introdudlory remarks 
he announces that, with the present discourse, he purposes 
commencing a series of unassuming presentations on 
some main questions of the Natural Sciences. Their 
solution by the co-operation of experimental and theo- 
retical research will alone render it possible for us one 
day to elaborate an accurate representation — satisfaftory 
to our craving for causality — of that certainly small por- 
tion of the universe which lies within our reach. He 
considers that, though his present theme is in appearance 
merely and specially physical, yet in reality it extends 
into the weightiest questions, not merely of physics, but 
also of chemistry, physical astronomy, and even of physi- 
ology. His immediate subjedt is the mechanical pro- 
cedures which lie at the basis of elecftrical phenomena, 
or, as the author puts it more cautiously and modestly, 
which seem thus to lie at the foundation. 

The misfortune is that Professor Griinwald's expositions 
are apt to be only dimly intelligible to other than 
physico-mathematical specialists. Had he been able to 
give some brief instances showing how his views lead us 
into questions oS chemistry and physiology, he would 
have reached a wider, and certainly not less appreciative, 
circle of disciples. 

As a summary of his results, he expresses himself to 
the eiTedt that the exad mathematical elaboration of the 
mechanical theory of ele>5lrical phenomena still requires 
difficult and profound study. We must especially get rid 
of the unsatisfaftory conception of actiones in distans — 
between matter and matter on the one hand, and between 
matter and ether on the other — as mysterious non- 
mediated effeds through a space supposed void and 
entirely without influence. 

In its place must come the new conception of these 
phenomena opened out by Faraday, Maxwell, Helmholtz, 
Lord Kelvin, Hertz, Boltzmann, and other illustrious 
minds, who regard such phenomena merely as the conse- 
quences of a chain of regular transferences of motion — 
or rather of semblances of motion— passiing from body to 



body within a dynamic space which co-operates with them 
in an essential, or indeed decisive, manner. 

According to the author's view, bodies are distinguished 
from each other, as relatively independent substances, by 
the substances of movement, and by their different 
position in universal dynamic space. The true inde- 
pendent and self-existing substance is the universe itself. 



Quantitative Estimation of Sugars. With explanatory 
notes by Dr. Ernest Wein. Translated, with addi- 
tions, by William Frew, Ph.D. (Munich), Wellpark 
Brewery, Glasgow. London : E. & F. N. Spon. 
New York : Spon and Chamberlain. Pp. 128. 1896. 
The translator points out in his preface that to obtain 
comparable results of Fehling's procedure certain pre- 
cautions are needful. He, in common with Dr. Wein, 
condemns the use of a fixed fador for converting either 
copper oxide or metallic copper into its equivalent of 
sugar. A common error committed is to boil the mixed 
solutions longer than the prescribed time. Another error 
is to add the cold Fehling's solution, heat and then boil 
for the specified time. In every case sugar solution must 
first be added when the Fehling's solution is in vigorous 
ebullition, and then continuing to boil for the specified 
I time. 

The arrangement for filtering off the precipitate of 
cuprous oxide in a Soxhlet tube is fully described. 

Soxhlet tube filled is shown as a frontispiece. The bulk 
of the work consists of tables for the determination 
respeflively of invert sugar in presence of beet-sugar, of 
invert sugar, of levulose and starch, and the volumetric 
determination of dextrose and maltose. 

Dr. Wein's work in its original German form is highly 
approved of by pradical men on the European continent, 
and it may be considered surprising that an English 
version has not appeared at an earlier date. Dr. Frew's 
translation only requires to be known to be highly 
valued. 



Notes on Qualitative Analysis. Arranged for the Use of 
Students of the Rensselaer Polytechnic Institute. By 
P. Mason, Professor of Chemistry. Third Edition. 
Easton, Pennsylvania: Chemical Publishing Company 
Pp. 56. 1896. 
Like not a few authors of elementary works on chemistry 
the writer admits that the world is overstocked with 
publications of a similar chara(5ler, and makes the 
familiar excuse that he seeks to meet the requirements 
of his own classes. In the preface he informs us that 
it is his practice to hold a daily " quiz-class " upon points 
conneded with laboratory work. A "quiz class" is, we 
conjei5lure, what is known in Germany as a repetitoriumi 
In the text we can find nothing objectionable, nor any- 
thing which has not been said already elsewhere. 



Notes for Chemical Students. By Peter T. Austen, 
Ph.D., F.C.S., Professor of Chemistry in the Polytechnic 
Institute of Brooklyn, Second Edition. New York: 
John Wiley and Sons. London: Chapman and Hall, 
Ltd, Pp, no, 1896. 
A BOOK, we submit, rarely rises in public estimation if 
the author finds it necessary to tender an apology for its 
appearance. But Professor Austen has little occasion in 
this manner to crave favour, since his work is quite able 
to plead its own cause. We may, indeed, in some 
respeds take exception to Dr. Austen's nomenclature. 
He writes "liter" for " litre." From the names of the 
halogens he lops off the final e, writing chlorin, bromin, 
&c. But vvhy^ not chlor, brom, &c, ? Carbonous oxid 
and carbonic oxid are, if we may use the expression, 
somewhat uncomfortable synonyms for carbon mon- 
oxide and dioxide. 



Chbuical Nbws. ] 
Jan. I, 1897. ] 



Chemical Notices jrom Foreign Sources, 



II 



In a quotation apparently from Professor Schiff, the 
author candidly admits that we have not the slightest idea 
of how to bridge the gap between matter and sensation, 
and proceeds as if the existence of matter were an 
undoubted fadt. He holds that " few words have been 
more abused than ' affinity.' " 

The secftion on *' water fadlors" brings under our notice 
a source of error which the American student encounters 
over and above those which we enjoy. The U.S. gallon 
represents only 8*3311 lbs. distilled water, whilst the 
British Imperial gallon weighs 10 lbs. Hence confusion 
and misunderstanding may arise. The author regrets 
that the use of the two vol. unit in chemical calculations 
is frequently omitted in English and American text-books. 

Vest'pocket Medical Dictionary. By Albert H. Buck, 
M.D. London: Bailliere, Tindall, and Cox. Pp. 529. 
1896. 
The objedl of this small but useful work is to explain the 
technical terms and abbreviations encountered in medical 
literature, which multiply with such uncanny rapidity as 
to puzzle, not merely scientific men whose specialities 
lie outside the medical profession, but even pradlitioners 
who have graduated prior to the last ten or twelve years. 
It will occasionally save gentlemen of the daily press 
from ludicrous mistakes. We were once staggered to 
read in an eminent political and literary organ, of a noted 
charadler dying from a gun-shot wound in the peritonitis ! 
This little book will preserve reporters and editors from 
committing themselves in such a manner. 



General Catalogue of the National Millenary Exhibition 
at Budapest, 1896. (" Catalogue General de I'Exposition 
Nationale du Millennaire, Budapest, 1896 "). Group 
XVIII. Chemical Industry. Edited by Dr. Leo 

LlEBERMAN. 

The total number of works here enumerated as chemical 
is 1253, employing 5702 men. Of these, however, goo 
are engaged at the various gas-works. In the production 
of soap and candles there are engaged 735 hands, and in 
the metal trades 697. Chemical manures engage 55 
persons, margarine 8, and gunpowder 3, though the 
powder mills are given as 8 ( ?). The match industry is 
eaid to be decreasing. Some of the branches of chemistry 
are in a flourishing state, whilst others are far from satis- 
fying the demands of the country. 



CHEMICAL 



NOTICES FHOM 
SOURCES. 



FOKtlGN 



Note.— All degrees of temperature are Centigrade unless otherwise 
expressed. 

Comptes Rendus Hebdomadaires des Seances, de V Academic 

des Sciences. Vol. cxxiii., No. 23, December 7, 1896. 

Pleurisy in Man studied by the aid of Kontgen 
Rays. — Ch. Bouchard. — A purely medical paper. 

Composition of the Gases evolved from the Mine- 
ral Waters of Bagnoles de I'Orme.— Ch. Bouchard 
and M. Desprez.— The gases would have the following 
composition in volumes :— Carbonic acid, 5-0; nitrogen, 
90-5 ; argon, 4-5 ; helium, traces ; total, loo-o. The 
presence of argon has been recognised in other sulphur 
springs. The waters of Bagnoles are not sulphuretted, 
but they are silicated like those of Canterets. 

Fr. Landolph submits to the judgment of the Academy 
a memoir on the optical analysis of urine, and the exa(a 
determmation of the proteids, ihe glucosides, and the 
non-fermentable saccharoidal matters. 

Determination of Phosphorus in the Ash of Coal 
and Coke.— Louis Campredon.— (See p. 8). 



Property of Discharging Ele(5trised Condu(!tor8 
communicated to Gases by X Rays, by Flames, and 
by Eletftric Sparks. — Emilie Villari. — A reply to the 
criticism of Ed. Brany {Comptes Rendus, Oft. 28th last). 

On Lithium Nitride. — M. Guntz. — Hydrogen, on 
thermo-chemical considerations, must decompose lithium 
nitride, as it is readily observed on heating LisN in 
a current of hydrogen. 

Formation Heat of Selenic Acid and of some 
Seleniates. — Rene Metzner. — A thermo-chemical paper. 
On comparing the different numbers with the corresponding 
values for sulphuric acid they are all found lower, 
except the heat of hydration. Whilst sulphurous acid 
fixes oxygen direftly, the oxidation of dissolved selenious 
acid is never diredt. 

Analysis of Industrial Copper by an Ele(5lrolytic 
Procedure — M. A. Holland.— This paper will be inserted 
in full. 

On Ozone and the Phenomena of Phosphores- 
cence. — Marius Otto. — The luminosity produced when 
ozone and water are in contact is due to the presence in 
the latter of organic matters, animal and vegetable. Most 
organic matters are capable of producing phenomena of 
phosphorescence with ozone. 

New Ammunition Bread. — Ballard, — This bread, 
unlike the old biscuit, contains salt and yeast. 

No. 24, December 14, 1896. 

The Rontgen Rays applied to the Diagnoses of 
Pulmonary Tuberculosis. — Ch. Bouchard. — In the 
diseases of the thorax radioscopy gives instruction com- 
parable in all points to that obtained by percussion. 

On Selenium Anhydride. — Rene Metzler. — A 
thermo-chemical paper. The endothermic charafter is 
observed very distindly on treating monohydrated selenic 
acid with phosphoric anhydride, according to the pro- 
cedure by which Berthelot succeeded in preparing nitric 
anhydride. 

Analysis of Industrial Copper of the Ele<5trolytic 
Process ; Determinations of Antimony, Sulphur, and 
Alien Metals.— A. Holland.— Arsenic and antimony are 
determined in the mother-liquor from which the copper 
has been precipitated eledtrolytically. Nickel and cobalt 
are determined eledlrolytically in the solution of the 
double sulphate and ammoniacal sulphate ; iron is deter- 
mined by permanganate. If the original copper was rich 
in silver, the copper which has been deposited upon the 
cone is dissolved, as it contains all the silver. In the 
contrary case a fresh portion of the copper is dissolved in 
nitric acid, and the nitric solution— filtered if needful— is 
vvith a chloride. The lead is determined in a fresh por- 
tion of the original substance, and is dissolved in dilute 
nitric acid. The sulphur is determined as barium sul- 
phate. 

Antimono-tungstic Compounds.— L. A. Hallopeau; 
— Antimonic hydrate can combine with tungstic acid to 
form antimoni-tungstic compounds, comparable to the 
phospho-tungstic and arsenio-tungstic combinations. 

Researches on Cobalt and Nickel Sulphides.— G. 
Chasneau.— It results, from the author's experiments, that 
the alkaline polysulphides, if saturated in the cold with 
sulphur, give in cobaltous salts a black persulphide, 
C02S7, insjluble in alkaline monosulphides, but soluble, 
on the contrary, in these sulphides if saturated with sul- 
phur. Under the same conditions the nickelous salts 
give a black sulphide, which appears to correspond with 
that of cobalt, but which, contrary to the latter, is 
scarcely soluble in sodium polysulphide, but decidedly 
soluble in the monosulphide. 

New Process for the Determination of Glycerin, 
— F. Bourdas and Sig. de R^czkowski.— This paper will 
be inserted in full. 



12 



Meetings for the Week. 



i Cbbmical News, 
1 Jan. I, 1897. 



MISCELLANEOUS. 

Society of Public Analysts. — The Annual Meeting 
of the Society will take place on Wednesday, January 
13, 1897, at the Chemical Society's Rooms, Burlington 
House, Piccadilly, at 5 o'clock p.m. The Year's 
Accounts will be presented. The retiring President will 
deliver his Annual Address. The following Papers are 
announced : — " Some Analyses of Water from an Oyster 
Fishery," " Note on Weighing Out Fats," " Remarks on 
Formaldehyde," by Chas. E. Cassal ; "A Specific Gravity 
Pipette," by W. F. Keating Stock ; " A Modified Schmidt 
Process," by R. W. Woosnam. 



MEETINGS FOR THE WEEK. 



MONDAVi \aa. 4tb. — Society ot Chemical Industry, 8. " Smelting and 
Refining of Cyanide Bullion," by A. Caldecott, 
B.A. *' Industrial Use of a Recording Pyro- 
meter," by Prof. Roberts-Austen, C.B., F.R.S. 

TUESDAY,5th. ) Royal Instituton, 3. (Christmas Ledtures, 1896-7). 

Thursday, 7th. V " Visible and Invisible Light," by Prof. Silvanus 

Saturday, gth. j P. Thompson, F.R.S., &c. 

CHEAP SETS OF STANDARD BOOKS. 

/» good condition, and sent Carriage Free in Great Britain. 
Philosophical Magazine, from commencement, 1798 to 1885 

(exc. I vol. and 7 >os.), 185 vols, half calf, <&c., very scarce, £6\, 
Watts' Di<;ty. of Chemistry and the Allied Sciences; complete set. 

UNABRIDGED EDITION, 9 VOls. clOth, I872-8I, jfl5, lOf £% 8s. 

Do , New Ed ,z\o\s.New,ii,&Z-q2(Specialo^er'\, £6 14s., for £4158. 
Thorpe's Difty. of Applied Chemistry {complete set) 1895. The 

companion work to " W.itts." 3 vols.. New, £7 ys. for £5 I2S. 
Chemical News, Complete Set, 1860—89, 6° vols., cloth, £18 los. 
Proceedings of the Royal Society of London, Completb Set, 

from 1854 to 1889; 39 vols., 8vo. cloth. Scarce, jf 10 10s. 
Philosophical Trans. Roy. Soc. Lend. Consecutive set, from 

1843 to 1889, 205 vols, or pts., cloth, &c., £50 (pub. ;^i89 9s. 6d.). 
Nature; complete set, 1869 to 1893 ; 48 vols , cloth, scarce, £12. 
Chemistry applied to Arts and Manufadlures by writers of eminence 

(Schorlemmer and others) ; engravings, 8 vols. (1880), £4, for 38/6. 
Gmelin's Handbook of Chemistry (Organic and Inorganic), by 

Hy, Watts, complete set, 19 vols, cl., scarce, £20. for £8 8s. 
Trans. Roy. Soc. of Edin., 178S to 1890, 36 vols., 4to., hf. calf, £45. 

WM. F. CLAY, Bookseller, Teviot Place, EDINBURGH. 



Established 1864. 

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STEEL WORKS ANALYSIS. 

By J. O. ARNOLD, 

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With 22 Illustrations and Diagrams. 
Crown 8vo., ios. 6i. 

CONTENTS :— The Steel Works— Laboratory and Appliances— 
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perience and salary expe(5ted, to No. 815, Robertson and Scott, 
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Purchased at highest prices by — 
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N.B.— Platinum Sold. 



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FORMALIN (4o°/> CH2O)— Antiseptic and Preservative. 

POTASS. PERMANGANATE— Cryst., large and small, 

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Crbmical Nbws, I 
Jan. 8, 1897. I 



Estimation 0/ Manganese in Spiegels, &c. 



13 



THE CHEMICAL NEWS 



Vol. LXXV., No. 1937. 



THE ESTIMATION OF MANGANESE IN 
SPIEGELS, &c. 
By H. BREARLEY. 

The acetate method of separating iron and manganese is 
very old. Its surname, whatever it may have been, is 
little heard of now. This is rather complimentary, 
because the much used methods are the more prone to 
suffer this change. Amid the quick young methods it 
seems to have lost virtues it was once credited with. 
There is more than a rumour, too, that its consort, 
precipitating with bromine and ammonia, and weighing 
as Mn304, is not so reliable as it was formerly supposed 
to be. 

Experience of the method in this laboratory has always 
been very satisfaftory ; but that opinion is by no means 
unanimous may be seen from the following references. 

Blair (" Chemical Analysis of Iron," Second Edition, 
p. 108) distrusts the Mn304, and recommends weighing 
as Mn2P207. A similar opinion is expressed in Crookes's 
•• Sele<a Methods " (Third Edition, p. 191). Fresenius 
(" Quantitative Analysis," Seventh Edition, p. 205) says 
that accurate results cannot be got with pyrophosphate 
unless the Mn is re-determined in the filtrate and wash- 
ings; whilst the oxides, ignited out of contaift with 
reducing gases, are finally converted with Mn304, whose 
weight remains unaltered. Arnold (" Steel Works 
Analysis," p. 81) says the ignition should be made in a 
hot muffle furnace, or the residue may not stridtly con- 
form to the formulae Mn304, which, under the above 
conditions, it will possess. Reddrop and Ramage (Jour. 
Client. Soc, 1895, P- 268) show that the ordinary gravi- 
metric method agrees with Pattinson's and the new one 
they describe. 

Great stress has been laid on the evidence afforded by 
Pickering's researches (Chem. News, xliii., 226). 
McKenna (Chem. News, Ixiii., 184) objeds to Mn304 on 
the evidence afforded by these papers, but later shows 
that ammonium manganous phosphate is soluble whether 
washed with water, ammonium nitrate, or dilute ammonia. 
Pickering himself recognises that his results are probably 
vitiated by the permeability of the platinum basins and 
consequent reducing adlion of the gases. The experi- 
ments of Morse and Burton (Chem. News, Ixvii., 175) 
made to test the point, furnish evidence in the same 
diredion. It is plain that changes might take place in 
an open platinum basin, over a Bunsen flame, which could 
not happen in a mufifle at full red heat. Under the latter 
conditions concordant results are always obtained. 

The general instrudlions for separating Fe and Mn are : 
iron in ferric state, cold solution, neutral or thereabouts, 
and an excess of acetate. In case of spiegels and high 
manganese alloys, the acetate precipitate is always re-dis- 
solved and re-precipitated to ensure a complete separa- 
tion. It was thought that the modification applied to 
iron and nickel (Chem, News, Ixxiv., 16) might apply 
also to iron and manganese, and thus obviate the need 
for a second precipitation. 

The excess of acetate necessary is variously stated 
•' more than sufficient excess to change all the iron and 
^nanganese by double decomposition to neutral acetates" 
(Crookes). 30 c.c. ammonium acetate* when half-a-grm. 
of Spiegel is operated on " (Arnold). " Two grms. 

. * Ammonium acetate used throughout refers to liquid acetic acid 
(33 per cent), neutralised with liquid ammonia. 



sodium acetate (crystallised) to precipitate i grm. of 
iron " (Blair), 

To show the effedl of free acetic acid 5 grms. of spiegel 
were dissolved and divided into five lots, neutralised, 
made up to nearly 1000 c.c. with cold water, 60 c.c. 
ammonium acetate added to each, and boiled. The hot 
solution was made up to a litre, cheesed,* 500 c.c. super- 
natant liquid filtered off, precipitated, ignited to constant 
weight, &c. The temperature at which the iron solutions 
became turbid was noted first at slight, and second, at 
decided turbidity. A "standard" sample was estimated 
at the same time by precipitating, washing, re-precipi- 
tating, &c., and gave first separation 2i'6i6 per cent; 
second separation, 0*389 per cent ; third separation, 
0*063 P^i" ^^'^^ f total, 22*068 per cent. 

The results of the five test estimations are colledted in 
the following table: — 



No. 
I. 

II. 
III. 
IV. 

V. 



Acetic 
acid. 

o c.c. 

10 ,, 

20 ,, 

40 „ 

70 .. 



Per cent 
manganese. 

2066 
21*14 
21*88 
22*02 
22*06 



Temperature of 
turbidity. 

56-60° C 
63-65 .. 
65-67 *. 
72-74 •! 
80-82 „ 



The FejOs, along with the Mn304, was certainly less 
than 00002 (except in V.), and this mostly due to a 
trace of iron in the bromine. The filtrates from the basic 
acetates were all clear ; the precipitates and excess of 
solution were left over-night, and it was found that the 
precipitates were bulky inversely as the acid addition ; 
I, was about three times as large as V., the others were 
intermediate. The supernatant liquids oftheI,,II,,and III. 
contained no iron, IV, a trace, and V. a decided quantity. 
The precipitates also varied in colour. I propose to 
examine these physical properties more closely. 

To wash the precipitated MnOa when it has been trans, 
ferred to the filter "till free from ammonia salts" or 
" thoroughly " is very troublesome, and sometimes impos- 
sible on account of the tendency it has to run through the 
filter as the ammonia salts disappear. There seems no 
reason why it should be washed at all in ordinary cases, 
since all the ammonia salts are volatile. Determinations 
with and without washing give closely agreeing results, 
aud two filtrates (about 800 c.c.) evaporated to dryness 
and ignited gave o*oi68 and 0*0134 grm. residue, which 
was mostly SiOg. Not more than 10 c.c. of this solution 
can be in the precipitate, and not more than 5 c.c. need be 
if it is thoroughly aspirated, so that any error introduced 
is insignificant, for technical work at any rate. This, of 
course, does not apply when sodium acetate is used or 
the spiegel contains unusual impurities. 

Some corrections which must be made when an aliquot 
part of a hot solution is taken, as above, will be men- 
tioned later. 

The great difference between the avidities of nitric 
and hydrochloric and acetic acid suggested the idea of 
adding acetic acid to the freshly dissolved spiegel, and 
then as much dilute ammonia as would neutralise the 
free HN03and HCl, form the required amount of acetate 
and leave sufficient free acetic acid. Tlie details need 
not be given, since the matter is curious rather than 
serviceable. After everything had been added the solu- 
tion was dark coloured, but quite clear. The percentage 
found on the sample previously mentioned was 21*93. A 
fortnight later two others in the same way gave 21*92 and 
22*05 per cent. 

These modifications shorten the ordinary method with 
its re-precipitations, without in any way impairing its 
accuracy. But there is still the tedium of weighing and 
and re-weighing, and the contamination of the Mn304 
and Cu, Ni, Co, &c., in case they are present in the 
sample. 

* " Cheesed " means to wrap a duster round the beaker, and then 
(old another over the cover to prevent cooling. 



14 



Estimation of Manganese in Spiegels, &c. 



CrbmicalNbws 
Jan. 8, 1807. 



I am not aware that Guyard's method of estimating 
manganese has ever been applied to the acetate filtrate. 
Of this method Sutton (" Volumetric Analysis," Fifth 
Edition, p. 190) says " Nickel, cobalt, zinc, alumina in 
moderate quantity are of no consequence. The method 
is easy of execution, and gives good results in cases 
where it can be properly applied, but such instances are 
few." 

Hopefully the filtrate was nearly neutralised with 
ammonia, and the standard permanganate run in. The 
end reaftion was fugitive, and the results at best were 
only fair. If a pink colour was produced, the precipitate 
at once filtered off, solution acidified in H2SO4, and 
excessof permanganate determinedwithFeS04, theresults 
were always too high ; and if filtered and allowed to 
stand the colour gradually disappeared, and MnOa was 
precipitated. This readtion continued long after all the 
manganese was precipitated, but was less decided in cold 
than hot solutions. It was found finally to be due to the 
ammonium acetate and other ammonium salts. This 
point was much elucidated later by reading that 
" ammonia boiled with a neutral solution of potassium 
permanganate was converted into potassium nitrate " 
(Tamm, Chem. News, xxv., 26). 

The more acetate, the greater discrepancy ; so that 
with as little as was necessary both of acetate and acetic 
acid the disturbing readion might be inappreciable in the 
cold. But how little acetate and acid could be used to 
efifedl a perfedt separation with one precipitation ? 

Experiment showed that 10 c.c. of ammonia acetate 
would precipitate i grm. of bar iron in i litre of solution. 
The supernatant solution was slightly turbid, but filtered 
crystal clear through asbestos. 20 c.c. of acetic acid 
with the same acetate did not prevent precipitation, but 
the solution needed twice filtering to make it crystal 
clear. 

A series of estimations made are given in the following 
table. It shows the efTedl of varying the acetate and 
acid under constant conditions, thus answering the 
question at issue, and also supplementing the table given 
above. 

Solutionsof bar iron and MnCla were mixed to approxi- 
mate a 20 per cent spiegel. The solution was made up 
anew for each vertical column, as available leisure did not 
admit of consecutive work on the series, the variation 
between column and column is probably due to this cause. 
To support this view the samples marked with an asterisk in 
columns 10 and 60 were made on the same solution and 
side by side. 



Acetate 
acid. 




Ammonium / 


Uetate, 




10 c.c. 


15 c.c. 


30 c.c. 


60 c.c. 


C.C. 


20-48* 


20*29 


20-00 


19-50 


5 » 


— 


2035 


— 


— 


10 „ 


— 


20-37 


20-38 


1974 


20 „ 


— 


20-35 


20-46 


19-91 


40 >. 


— 


— 


20-48 


20-19 


60 „ 


"~" 


~ 


~ 


20-18 
20-47 



Acetic 



Ammonium Acetate. 



icid. 


10. 


15- 


30. 


60. 





20-0 


19-94 


19-52 


19-33 


5 


— 


20*00 


— 


— 


10 


— 


20-02 


19-90 


19-56 


20 


— 


20-00 


19-98 


1973 


40 


— 


— 


20-00 


20-01 


60 


— 


— 


— 


20-00 



If we assume that each perfeft separation— the one 
with most acid in — represents an even 20 per cent, and 
calculate the other results proportionately, the influence 
of acid and acetate is more readily seen. 



Wright and Menke's (jfonr, Chem. Soc, 1880) modifica- 
tion of Guyard's method, some very good results were 
obtained. 

Soda acetate in minimum quantity with soda salts 
behaves well in either hot or cold solutions. Half-a-grm. 
of crystals, after neutralising i grm. bar iron with 
sodium carbonate, brought down a precipitate, but left a 
supernatant yellowish liquid no amount of filtering would 
decolourise. Three-quarter grm. of crystals gave a clear 
filtrate, and the tint imparted by two drops of N/io 
KMn04 was not appreciably affefted when the solution 
was heated to boiling. The difficulty might have been 
eliminated at once by using soda salts, but it was thought 
desirable to retain ammonia if possible, so that the gravi- 
metric or volumetric methods might be applied to the 
filtrate at will. 

Briefly the method is — Dissolve spiegel in HCl, oxidise 
the iron with HNO3, neutralise with soda or ammonia, 
and precipitate Fe with acetate (sodium or ammonium) in 
minimum quantity. Nearly neutralise filtrate, and 
titrate with permanganate. This outline is given so that 
there may be something to definitely refer to. The 
method of titration preferred is Wright and Menke's in 
cold solutions. This is better than titrating in hot solu- 
tions because the KMn04 is less likely to be afTedled by 
accidental or unavoidable organic matter, &c. This is 
strongly emphasised by my experience. No distilled 
water v/as handy, our ordinary tap water was used, and 
titration performed in hot solutions. The results were 
very unsatisfa(5tory. Of course, ordinary water ought not 
to have been used, but such a contingency in aftual work 
is not unimaginable. 

The following mixtures of iron and manganese chloride 
solutions, mixed to approximate spiegels and ferro-man- 
ganese, show that the method gives exceedingly accurate 
results. 



Per cent manganese 
Present. Found. 



N/io KMnOtCapprox.) 
required by — 



10 
10 
20 
20 
40 
60 



10*09 
9-99 
19-99 
19-99 
40-00 
59-87 



Theory. 
30-03 C.C. 

30'03 .. 

60*06 ,, 

60*06 ,, 

89-5 ,. 

89-5 M 



Sample. 

30-3 

30*0 

59-96 

59*96 

89*5 

89-3 



Salts 
used. 

Soda. 

Ammonia 

Soda 

Ammonia 

Soda 

Soda 



Keeping the ammonia salts as low as possible, and pre- 
cipitating with only 10 c.c, of acetate, and titrating with 



I am obliged to Mr. R. L, Lefifler, the chemist in this 
laboratory, for making a trial of the method. I furnished 
him with an account of the method and some solutions 
marked with the approximate composition. He reported 
as follows : — 

Given as (per cent) .. .. 1200 23*00 40*00 65-00 82-00 
Found (per cent) .. .. 10-76 21-99 40-16 64-40 79-78 
They really contained (p. c.) 10-80 22-00 40-00 64-00 80*00 

Soda salts were used throughout. 

When so small a quantity of acetate is used, the iron 
solution must be neutralised pretty accurately, or it will 
not be clearly precipitated. A trouble of this kind might 
be obviated by adding soda carbonate to slight turbidity, 
and dissolve in, say, 5 acetic acid. The influence of this 
acetic, even when larger amounts of soda acetate are 
used, is seen from the following amounts of permanganate 
used. 

Acetic Soda acetate (20 c.c.=3 grm. crystals), 

acid. 20. 30. 40. 60 c.c. 

o c.c. 59-5 589 SS'i 56-5 c.c. 

5 I. •• 59-9 59-85 59-4 .. 

The quantity theoretically required was 59-75. 

In such cases as the foregoing, where an aliquot part 
of a hot solution containing a precipitate is filtered off, 
there are certain corredions need making. Say the total 
bulk of solution and precipitate is 1000 c.c, and 500 c.c. 
of the clear solution is filtered off. From this 500 c.c. 
there must be subtraded (i) half the volume of the pre- 



CitCIIICAt. Nbws,1 
Jan. 8, 1897. I 



Estimation of Manganese in Spiegels, &c. 



15 



cipitale ; (2) the volume contradled from the temperature 
when 1000 c.c. is measured to the temperature when 500 
c.c. is measured ; (3) a slight corredlion due to the con- 
centration of the solution while filtering, &c. In case of 
Bpiegels the volume corre(5lion for bulk of precipitate is 
less than i c.c, so of no moment. The corredtion for 
contradion was carefully considered. The most conve- 
nientway seemed to be to note the temperature in the litre 
flask, the temperature in the half litre, and calculate the 
contradtion due to cooling. To this end the contradlion 
of an ordinary 20 per cent Spiegel filtrate was observed, 
and found to behave so much like water that Kopp's 
tables for that body have since been used. In some 
scores of cases observed the temperatures have not varied 
more than 2° C. under uniform conditions of working. It 
is not easy to fix a value for the third error. It depends 
on the form of vessel used, the rapidity of filtration, and 
other incidents which vary in an indeterminable way. 
Arnold {" Steel Works Analysis," p. 82) allows 5 c.c, 
when the volume of solution is 600 c.c, and later only 
I c.c. when the volume is 300 c.c. These also include 
the volume of the precipitate. 

It were best to avoid this error altogether if possible. 
The following means were taken to minimise, if not alto- 
gether eliminate it : — The precipitation was made in 
flasks, Taylor pattern, marked at 1000° C. ; the boiling 
solution was transferred to a litre flask with graduated 
neck, the volume noted, and the litre inverted in the pre- 
cipitating flask. The precipitate readily settled, and then 
the clear solution was filtered by the arrangement shown 
in the figure. The filtration is very rapid, because little 
or no precipitate falls on the filter. 




If small quantities of suspended precipitate made no 
difference to the subsequent titration, the filter tube might 
be dispensed with, and half a litre simply syphoned off. 
Results of experiments in which the iron was introduced 
as an emulsion of the precipitated basic acetate were — 





Grm. 


Grm. 


Grm, 


Grm. 


Fe present . . 


0*0000 


o'ooo7 


00033 


0*0050 




C.c, 


C.c. 


C.c. 


C.c, 


KMn04Used.. 


3175 


31-8 


3175 


31-6 



Throughout these experiments the precipitated MnOa 
was frequently dissolved in ferrous am. sulphate, and 
the excess titrated with standard bichromate. This is an 
obvious way of confirming an estimation. 

One other point, the standardisation of the permanga- 
nate solution, needs to be carefully noted. Simple 
standardisation with bar iron or flower wire, dissolved with 
precaution in H2SO4, has always given a value 1 or 2 per 



cent below what we had good reason to suppose was the 
real percentage. McD. Irby (Chemical News, xxx., 142) 
has shown that the small amounts of carbon present in 
the iron has an effedl amounting to between i and 2 per 
cent, so that the iron solution needs to be oxidised to 
destroy the carbonaceous matter, then reduced and the 
titration performed. As this point seems to be generally 
overlooked, and as it introduces an error of several tenths 
per cent on a 20 per cent spiegel, it is being studied in 
connexion with a series of experiments on Sarnstrom's 
method of estimating manganese. Up to now we have 
found it convenient and accurate to standardise with a 
Spiegel containing a known percentage of manganese, 
or with a manganese salt whose purity was beyond 
question. The value of the last lot of permanganate 
determined by three separate spiegels was— 

1. 0001662 Mn per z c.c. 

2. o'ooi667 ,, 

3. o'ooi664 ,, 
By pure manganese salt O'ooi664 „ 

Conclusion. 

After the gravimetric part of this paper was done, I 
was under the impression that separating iron and man- 
ganese in presence of considerable quantities of acetic 
acid was a new idea ; and the same may be said of pre- 
cipitating with minimum amounts of acetate, I think i 
will make this paper more complete than otherwise if I 
give the references of papers that have come to my 
notice. 

Debray (Chemical News, xxi., 53).—" The acetate of 
sesquioxide of iron separated, on boiling, into acetic acid 
and colloidal oxide Colloidal oxide of iron is in- 
soluble in ammonia salts, even in presence of a large 
quantity of acetic acid." 

Jewett (Chemical News, xl., 5J73) shows that, with 
large quantities of soda acetate, acetic acid — amounting to 
5 per cent of the volume of solution— causes the complete 
separation of Zn and Mn from iron, and a nearly com- 
plete separation in case of Ni and Co. On the authority 
of E. H. Smith, the same paper states that iron could not 
be precipitated, in presence of large amounts of acetic 
acid, by increasing the soda acetate. My observations 
are contrary to this. The error may be seen by precipi- 
tating, in presence of 70 c,c. acetic acid, with minimum 
acetate and several grms. 

Kessler (Chemical News, xxvii., 14), — -'The loss ex- 
perienced in the estimation of the manganese by the 
acetate (soda) method is mainly due to the fadt that too 
large a quantity of acetate of soda is employed, in con- 
sequence of which a portion of chloride of manganese is 
converted into acetate, which salts is readily converted 
into protoxide and acid." 

I am sorry to have unknowingly gone over previously 
trodden ground, but the persistent way in which the in- 
strudlions to use unnecessarily large amounts of acetate 
and neutralise all free acid are repeated, even in the most 
recent text-books, makes it perhaps not altogether inop- 
portune that this matter should be again brought forward. 
It is plain that the results here set forth point to a modi- 
fication of the method previously proposed for nickel 
and iron separation, in the interest of economy, if not 
accuracy, 

Mr, Leffler suggests that the volumetric method be 
applied to steels. For steels of the ordinary class it offers 
no advantages over a number of already well-known 
methods, such as Ford and Williams'. In those cases, 
where several percents of chromium are present, it may 
prove useful, since such steels are frequently not com- 
pletely soluble in nitric acid. 

The various points enumerated are here colledted into 

The Method. 
Dissolve I to i'5 grms. of the spiegel (20 per cent) or 
proportionate amounts of other uianganiferous irons, in 



I6 



Manufacture of Calcium Carbide, 



i CHBkicAL News, 
\ Jan. 8, 1897. 



hydrochloric acid, and oxidise the iron with nitric acid. 
If the silica present is likely to interfere with the neutral- 
isation, pass through a small asbestos filter. Neutralise 
with soda carbonate, dilute to about goo c.c, and add soda 
acetate at the rate of 20 c.c. per i grm. of iron. Ammo- 
nia and ammonia acetate may be used, bearing in mind 
its limitations. See that the boiling solution touches the 
litre mark on the flask. Transfer to the litre measure with 
graduated neck. Note temperature and volume, and re- 
place in the precipitating flask. Cheese, syphon, or filter 
off half the noted volume, and take the temperature. Cool, 
destroy the free acid with soda carbonate, and then make 
slightly acid with acetic or dilute sulphuric. Run the 
amount of permanganate into a flask, and add 10 c.c, 
ZnS04, and run in the manganese solution with constant 
shaking. This may readily be done by placing a wide- 
stem funnel in the larger flask, holding it in position with 
the first finger of the right hand ; the lower fingers grasp 
the neck with the flask resting against the thick of the 
hand; the solution is shaken, while the left hand pours 
the manganese solution through the nearly stationary 
funnel. The percentage of manganese in spiegel is gene- 
rally approximately known. Failing this an approxima- 
tion may be speedily obtained by syphoning off an 
additional 250 c.c. and precipitating hot (Guyard). 

The well-shaken liquid containing the small excess of 
permanganate is allowed to settle a few minutes, an 
aliquot part filtered off, acidified, and determined with 
ferrous ammonia sulphate and permanganate. 

After correding the figures for volume contraAion the 
calculations need no further explanation. 

The following values, from Kopp's tables for water, 
given here, will save further reference. 

If the volume of water = i at 0° C, it changes when 
heated to the following volumes : — 

70° C, I '02225 ; 85° C, I "03189; 
75° „ ro2S44; 90° „ i '03540; 
80° „ 1 '02858; 95° „ 1-03909. 

Reagents required :— 

Potassa permanganate 3'i56 grms. per litre. 
Soda acetate .. .. 37*5 ,, 

Zfnc sulphate .. .. 200 ,, 



a piece of carbide of from 300 to 400 pounds. The car- 
bide itself is crystalline. The crystals are especially well 
developed near the top, and are more perfedt with an 
excess of coke, low voltage, and when allowed to cool 
slowly. The centre of the piece of carbide stays liquid 
for some time after the electric current has been shut off. 
The liquid part, however, is of the same quality as the 
rest of the piece. We have, in facft, tapped out of the 
furnace carbide which was very pure and yielded 5*59 
cubic feet of gas per pound. We do not wish to express 
an opinion as to the practicability of tapping the carbide 
as soon as it is formed. We will only mention that Mr. 
Price, in Newark, has, with a view of tapping the car- 
bide, construdled and patented a new furnace, and that 
one of us (C.) has also devised a furnace for the same 
purpose. 

Carbide of average quality (about 5 cubic feet of gas 
per pound) often has a reddish colour, especially if it has 
been made with a current of high voltage. Carbide of 
bad quality is often greyish or blackish, or will show 
streaks of graphite. Pure carbide yields more than 5'go 
cubic feet of gas per pound. It has, however, been found 
to be more economical to produce carbide that yields only 
about 5 cubic feet of gas per pound. Samples of carbide 
of different qualities contained : — 



Laboratoryi Norfolk Works, Sheffield. 



THE MANUFACTURE OF CALCIUM CARBIDE.* 
By J. T. MOREHEAD and G. de CHALMOT. 

(Continued from p. 5), 

The carbide is always found in one piece between the 
pencils and the bottom. It has a conical form, being 
broader at the base, and can be 2.J feet high in our 
furnace. It, however, never has so great a diameter as to 
fill up the whole capacity of the furnace. The carbide is 
therefore entirely surrounded by a cover of the mixture of 
lime and coke. This mixture is so bad a condudor of 
heat that the brick walls of the furnace are not attacked. 
It is very easy to separate the carbide from the loose 
mixture, for the latter never melts together, while the 
carbide is hard and solid. The pieces of carbide are 
covered with a thin coating which is a little thicker at the 
top of the piece, and the same may be re-ground and again 
used. This coating contains mainly carbon, but also car- 
bide and calcium oxide. It seldom yields more than half 
a cubic foot of gas per pound, but in some cases it yields 
1*77 and even 2'io cubic feet. This coating, however, is 
of little importance. If the mixture is well made this 
coating seldom exceeds from twenty to thirty pounds on 



* Read Sept. 3rd before the Springfield meeting of the A.A.A.S. by 
one of us (M ). We have made since then several additions, so as to 
make the article complete up to the present time. From the Journal 
of the American Chemical Society, April, 1896. 







Table I. 






Cubic feet 


Carbide. 


Free calcium 


Carbon 


Other im 


gas per 


Per 


oxide. 


Per 


purities. 


pound. 


cent. 


Per cent. 


cent. 


Per cent. 


57 


966 


o'6 


— 


2'8 


55 


93-2 


4'2 


— 


2-6 


5'i 


864 


9-5 


— 


4' I 


5-025 


847 


io'7 


i'6 


3.0 


3-6 


6i'o 


275 


32 


8-3 


3-45 


58-5 


I'l 


25'6 


148 



The upper part of a piece of carbide is often purer than 
the under part. 

The coke to be used should not contain much ash. Our 
coke contains about 7 per cent of ash. The carbide ob- 
tained with a coke of from 10 to 11 per cent of ash was 
perceptibly inferior to that obtained with our usual coke. 
It was found impradicable to make a good quality of car- 
bide with a coke of 27 per cent ash. It is well that there 
should not be more than 10 per cent of ash in the coke. 
The coke should be ground very fine, and it should pass 
through a fifty-mesh sieve. The lime need not be as fine 
as the coke. The largest pieces should pass through a 
ten-mesh sieve. If the lime is coarser the quality of the 
carbide becomes inferior. That the state of the pulverisa- 
tion of the lime is important can be seen by a comparison 
of the average amount of gas per pound (4'97 cubic feet), 
obtained with unslacked lime (Table II.), and that ob- 
tained with air slacked lime (5*27 cubic feet. Table III.). 
The unslacked lime was in several instances not quite as 
fine as the slacked lime. Unslacked lime is decidedly 
preferable to air slacked lime, as we will see afterwards. 

The lime which we use contains ij per cent magnesia 
and I per cent of other impurities. The anhydrous lime 
should contain 95 per cent calcium oxide and no more 
than 5 per cent impurities. The presence of magnesia is 
especially detrimental to the produdlion of carbide. We 
could not obtain a good quality of carbide with a lime in 
the following analysis: — Insoluble, 0*24 per cent; silica, 
o'78 per cent ; ferric oxide and alumina, o'68 per cent; 
calcium oxide, 92'83 per cent; magnesium oxide 5*47 per 
cent. Further experiments showed that 2^ per cent of 
magnesia in the mixture has a marked influence on the 
produdion. The lime used for making carbide should not 
contain over 3 per cent of magnesia. That magnesia has 
such a bad influence upon the formation of carbide is pro- 
bably due to its forming a veil between the carbon and the 
lime particles, preventing their combination. Magnesia 
does not unite either with lime or with carbon. The 
latter fad was first shown by Moissan {Compt. Rend., 



Chbuicai NbW8|I 
Jan. 8, 1897. f 



Manufacture of Calcium Carbide. 



17 



1181 506), and our own experiments in this line fully con- 
firm his results. The lime and the coke must be mixed 
very well or the carbide will be of inferior quality, and 
there will be much coating. Besides the carbide some 
mixture remains in the furnace. More carbon than lime 
burns out or volatilises in an open furnace. It is there- 
fore necessary to add carbon to this mixture before using 
it again. The amount to be added is calculated from the 
result of an analysis of the mixture. If coke is added in 
the proper proportions the unsmelted portion of the mate- 
rial can be returned at least three times into the furnace 
and still yield good carbide. The impurities of the lime 
and the coke ashes remain as well in the carbide as in the 
residual mixture. It is therefore a good pradice to add 
charcoal instead of coke to the mixture, so as not per- 
ceptibly to increase the amount of ash. The mixture 
that comes from the furnace is red hot, and it will stay 
hot for days. It will lose a large amount of carbon if 
allowed to lay in heaps in the air. It is better to mix in 
the necessary amount of carbon and use the mixture at 
once again. One can also keep the mixture in air-tight 
sheet-iron tanks. If the lime has been unslacked the 
mixture cools much quicker and does not lose as much 
carbon after it has been taken from the furnace. In the 
case of slacked lime water gas is probably formed in large 
amounts. The carbon pencils must be well cared for in 
order that they last for a long time. If sufHcient coke is 
put in the mixture they are not attacked much at the end. 
They will shorten from 0*05 to cio inch for every hour 
running. They become thinner for being exposed to the 
air when hot. They are mainly attacked after the eledric 
current has been shut off, for if the furnace is working the 
gases from the arc come up around the carbons and shut 
the air off. In order to save the carbons best it is there- 
fore well to keep the furnaces running with as little in- 
terruption as possible. In the closed furnace, which we 
have described, the carbons will be surrounded by non- 
oxidising gases, which will save them materially. In the 
open furnaces in Spray we surround the carbons with a 
sheet-iron cover that reaches from the carbon holder to 
within four inches of the bottom end of the carbons. 
This jacket is fastened with iron wires to the carbon 
holder. The space between the carbons and the jacket 
is packed with a mixture of coke and coal tar or pitch. 
This mixture is baked by surrounding the carbons and 
jacket with the red hot material that comes from the 
furnace, or by placing them in a fire. The jacket will 
generally last as long as the carbons. One set of the 
carbons in an open furnace, and with interrupted opera- 
tions, will last on an average about 100 hours. These 
figures hold good where a current of from 1700 to 2000 
amperes is used. The voltage has no perceptible influ- 
ence on the result. Working with say 1700 amperes and 
100 volts, and generating about 225 horse power, the pro- 
du(5lion of carbide per hour can be reckoned to be easily 
eighty-five pounds, and one set of carbons can therefore 
make at least 8500 pounds of carbide, even in an open 
furnace. If the furnace is used continuously the carbons 
will last at least from 200 to 300 hours, and the cost of 
pencils for one ton of carbide will be about i dol. 

The analytical part of our work has been very simple. 
After the piece of carbide has been broken open with a 
hammer, two or more samples, representing as nearly as 
possible the average quality of the carbide, and of about 
eight ounces each, are taken. These samples are broken 
in pieces of about half an inch in diameter, and from two 
to three ounces are taken for one gas test. The material 
is put into a dry bottle of about one quart capacity, 
which is provided with a rubber stopper, through which 
two glass tubes pass. The one tube bears a stop cock 
and drop funnel, the other tube condudls the gas through 
a series of [J tubes and then through a small gas meter. 
The funnel is filled with water, and, by opening the stop- 
cock, water is allowed to drop slowly on the carbide. 
The acetylene gas is generated and is cooled in the (J 
tubes before it passes to the gas-meter. Much water 



vapour is condensed in the U tubes, for the gases gene- 
rated in the bottle are hot. We make a correcStion for the 
temperature of the gas as it passes the gas-meter. We 
do not take into consideration the small amount of gas 
which passes through the gas meter by the expansion of 
the gas in the bottle when the latter becomes hot, and 
because a part of the bottle becomes filled with water. 
The error arising herefrom is of no consequence, for the 
volume of the bottle is only one quart, and the volume of 
the gas which passes from the gas meter is from \ cubic 
foot to I cubic foot. The water, moreover, becomes 
saturated with acetylene. Our figures show the amount 
of moist gas at the temperature of 60° F. 

In order to determine the lime in the mixture, two and 
five-tenths grms. are boiled with a slight excess of hydro- 
chloric acid of known strength in a 250 c.c. bottle. The 
bottle is cooled and filled up. The liquid is filtered, and 
in 50 c.c. of the filtrate the excess of acid is determined 
by titration. The coke is determined by boiling 2 grms. 
of mixture with 25 c.c. of 12 per cent hydrochloric acid 
and filtering off the coke on a Gooch crucible. These 
methods do not make a claim to absolute accuracy, but 
they can be quickly executed and give a good estimate of 
the relation in which the coke and lime are present in the 
mixture, as the following figures show. The coke used 
for the original mixture contained 7-33 per cent of ash. 
The coke that remained from the mixture that had been 
boiled with 12 per cent hydrochloric acid contained 65*5 
per cent of ash, and the coke which remained by the same 
treatment from a similar mixture that had been once in 
the furnace contained 7/0 per cent ash. The amount of 
lime found in mixtures by titration, and that found by 
gravimetric analysis, varied only by from i to J per cent 
when the small amount of magnesia in the lime was 
known and taken into consideration. In controlling the 
different runs we have proceeded as follows : — 

The carbide was weighed and the coating on it deter- 
mined either by taking it off and weighing it or by esti- 
mating it on small and clean pieces. By deduifting the 
weight of the coating from the weight of the piece of 
carbide we obtain the net yield of carbide. The gas 
therein is determined, the figure accepted being the 
average of the result of the analyses of at least two 
samples. In order to determine the power used, we 
multiply the voltage by the amperage and divide the pro- 
du(5t by 746 to obtain the number of horse power gene- 
rated by the dynamos. In order to make a more proper 
comparison we found it necessary to dedudt the loss of 
voltage sustained in the carbon pencils. Our pencils 
were made in different fadories and had a different re- 
sistance. We therefore determined the difference in 
voltage as indicated by the usual reading of our meter 
and the voltage at the end of the carbon pencils. We 
touch the end of each pencil alternately with an iron rod 
that is connedted with the volt meter by a copper wire. 
We call net power the power generated by the dynamos 
less the average loss in the six carbon pencils. Our 
meters are placed in the primary circuit and we have not 
taken into account the losses of amperage in the trans- 
formers and those sustained by leakage. We have fur- 
ther found that the readings of our meters are about 6 
per cent higher than those of standard Weston meters. 
It may therefore be safely relied upon that all our esti- 
mates for the production of carbide per horse power are 
too low. The error is, however, in all cases in the same 
dire(51:ion, so that it cannot have materially influenced 
our deductions, which are based upon a comparison of 
our results. 

In the carbide there is also a considerable loss of 
voltage, and therefore of power. We found, for example, 
sixty-five volts in the bottom cables and only fifty volts at 
the top of a 2J feet high piece of carbide just under the 
arc. This makes a loss of six volts for each foot of car- 
bide. The average produdion during six to eight hours 
of continuous working is as large as that during two or 
three hours at the same power. It is, however, not ad- 



i8 



Derivatives of Colutnbium and Tantalum. 



f Chbuical News, 
I Ian. 8, 1897. 



visable to make the carbide pieces higher than 2 i feet, 
since then the resistance of the carbide will begin to 
materially reduce the quantity of the produ^ion. 
(To be continued). 



The quantitative analysis of this columbite by fusing 

with bisulphate, as above described, gave the following 

results : — „ 

B. C. D. E. 



DERIVATIVES OF COLUMBIUM AND 

TANTALUM* 

By MARY ENGLE PENNINGTON. 

{Contiuued rrom p. 10). 

The mineral was ground very fine and heated in sealed 
tubes with sulphuric acid (i part of concentrated acid to 
2 parts water), the resulting decomposition being titrated 
with permanganate, with the following results :— 

Per cent FeO. 

0"5 grm. heated one day at 210° C i'3i6 

o*5 grm. heated two days at 230° C. . . i'4i6 
o"5 grm. heated five days at 230° C. . . 5 "50 

It seemed probable that this was not the total amount 
of ferrous iron in the columbite; hence attention was 
direfied to an old method which is rarely used, yet seerns 
to be worthy of greater attention than has been given it. 
Berzelius first suggested the method, though it is gene- 
rally credited to Hermann. The finely ground mineral is 
mixed with fused and finely divided borax. A small 
platinum crucible is completely filled with this mixture, 
then covered with a platinum lid, and the whole placed in 
a larger platinum crucible. Dry magnesium oxide is 
packed around and over the inner crucible until it is com- 
pletely covered, and so excluded from air contadl. The 
heat of a good Bunsen lamp is applied for one-half hour, 
when the decomposition is complete. Longer heating, or 
too rapid cooling, causes the fusion to adhere very tightly 
to the crucible, and loss may result on endeavouring to 
remove it. When the whole is quite cold, the small crucible 
is taken out, freed from adhering magnesium oxide and 
weighed. The fusion, which is a clear green glass, is 
then freed from the crucible by sharply tapping ; a piece 
may be broken off, weighed, ground in a tnortar, dissolved 
in water and sulphuric acid, and titrated with potassium 
permanganate. Or, if the amount of ferrous iron is not 
large, it is better to crush the whole fusion in a diamond 
mortar, then place in a flask provided with a Bunsen 
valve, dissolve in water and suiphuric acid, and titrate. 
To prevent the oxidation of the iron during its solution, 
a quantity of sodium carbonate was placed in the flask 
with the ground fusion, and the water and sulphuric acid 
added carefully to this mixture. When a strong evolution 
of carbon dioxide had continued for several minutes, the 
cork carrying the Bunsen valve was quickly inserted, and 
the flask put aside until solution had taken place. It is 
necessary to shake the flask from time to time, otherwise 
the finely divided oxides which separate will enclose 
some particles of the fusion, and the result will be low. 
In one or two hours the insoluble residue should be a 
perfectly white, fine, homogeneous mass. The flask is 
then opened, more sulphuric acid added if necessary, and 
the iron titrated with permanganate. A number of 
fusions were made according to this method, the amount 
of ferrous oxide found being 6'426 per cent. The 
method seems to be, so far as columbite is concerned, 
perfedlly trustworthy. It is rapid and the manipulation is 
not difficult. The oxides which separated out were per- 
feftly white. In one experiment they were filtered off, 
washed with hot water, ignited, and weighed. The per- 
centage of mixed oxides, 77*94 per cent, agrees quite well 
with that obtained by the bisulphate method. 

* From the author's thesis presented to the University of Penn- 
sylvania for the degree of Ph.D., 1895. From the Journ. Amer. 
Chem. Soc, xviii., January, 1896. 



iOsf 

:>z ) 



TajOj 

Cba 

TiOa 

FeaOs 

SnOa \ 

WO3 J 

MnO.. 



A. 
78-61 



12*30 

115 

8-96 



I '60 
8-32 

101*02 102*79 



79*04 79'00 77*96 78*70 

13-83 13*62 13*58 — 
1*85 2*24 



1*84 
J -08 — 



— 100*86 — 



One-half grm. of material was used in each case, 
The ferric oxide, as given above, includes the ferrous, 
which, estimated by the method of Berzelius, equals 
6-42 per cent. 

In a sixth analysis 3 grms. of material were taken 
and due attention was paid to those constituents which 
former analyses had shown to be present, but in such 
small quantities that their determination was not trust- 
worthy. The results in this case were :— 

Per cent. 
TaaOj) 

CbaOsj. 78*04 

TiOj ) 



WO3 
SnOa 
U3O8 
FeaOa 
FeO . 
CaO . 
MnO. 
H2O. 



Total 



0*24 

0-48 
5-22 
6-42 

0*02 
8-96 
1*22 

100*60 



An interesting point in the composition of this colum- 
bite is the ferric oxide. Hermann records one analysis 
of some fragments of a columbite from Miask containing 
several per cent of it, and so far as I am aware this is 
the only columbite in which this constituent is mentioned. 
He also gives a Miask columbite containing 0*50 per 
cent of uranium oxide. Genth mentions a trace of 
uranium in a columbite analysed by him. 

While no effort was made to separate the metallic 
oxides quantitatively, it was found from the preparation 
of pure material that the columbium was in decided 
excess. Titanic acid was proved to be present, and silica 
was found in very small quantities. 

Many of the recorded analyses in which separations of 
columbic and tantalic oxides are given, fail to state whether 
any attempt had been made to eliminate or to prove the 
presence of titanium or silica. Given a mixture of tan- 
talum, columbium, and titanium, the analyst will have 
no difficulty in separating tantalum from columbium by 
Marignac's double fluoride method. But the titanium 
double fluoride, when mixed with the columbium salt, 
shows an abnormal solubility which makes its separation 
very doubtful. This point will be more fully discussed 
later. 

Fusion with Sodium Thiosulphate.— It occurred to me 
to try the decomposition of the mineral by fusion with 
sodium thiosulphate, believing that in this way tungsten 
and tin would be converted into sulpho-salts, and could 
then be more effeaually removed from the other constitu- 
ents. Without entering into detail, I may say the attempt 
was fruitless. 

Decomposition by the Gibbs Method.—Some years ago 
Dr. Gibbs published a procedure {Am. J. Sci. Arts, xxxyii., 
357, 1864) for the decomposition of the columbite mine- 
rals ; and as my desire was to investigate the different 
methods of decomposition, I naturally turned to this 
suggestion. In mineral literature this course is given a 
second place to the bisulphate decomposition. My own 



CHRMtcAL News, I 
Jan. 8, 1897. I 



Derivatives of Columbium and Tantalum, 



19 



experience compels tne to prefer it to the latter 
method. The details of the Gibbs method are, in brief, 
as follows : — 

The mineral must be fine, yet need not be in an impal- 
pable powder, as is necessary in the bisulpha'.e decomposi- 
tion ; it was intimately mixed, by grinding in a mortar, with 
three times its weight of potassium fluoride ; the mixture 
was transferred to a platinum crucible and made into a 
paste with concentrated hydrofluoric acid. The mass 
heated up at once, and for some minutes the decomposi- 
tion proceeded without the application of heat. It was 
found advantageous to let this mixture of acid salt and 
mineral stand for several hours, stirring occasionally, and 
adding more acid if the mass became hard. It was then 
heated on a water-bath until the excess of acid was driven 
off. After thoroughly drying on an iron plate, the 
free flame was applied. Hydrofluoric acid was driven 
out of the acid potassium fluoride, and at length the whole 
mass fused and formed a clear, quiet, easily handled fusion, 
which, upon cooling, became a beautiful pink-violet in 
colour. 

The decomposition is not complete until every part of 
the mixture has assumed this colour, which does not 
change on further heating. In the early part of the 
fusion a deep blue colour appears. If the adlion be in- 
terrupted at this point an incomplete decomposition will 
result. 

The violet mass was taken up with water and hydro- 
fluoric acid in a platinum dish, then boiled and filtered. 
This extra(5tion should be repeated several times. If the 
decomposition is not quantitative, the solution in water 
is much hastened by first grinding the fusion. Any silica 
which may have been present in the mineral will remain 
as potassium silicofluoride. This being a gelatinous 
compound, it is likely to enclose fine particles of the 
fusion and prevent their solution. If the amount of 
silica is not large, a separation may usually be effeded by 
treating with concentrated hydrofluoric acid ; but if much 
silica be present it is safer to evaporate to dryness with 
alitile sulphuric acid, and take up the remaining potassium 
sulphate with water. If any insoluble substance is left 
it may be dissolved in hydrofluoric acid and added to the 
main portion of the solution. 

If an analysis of the mineral is desired, hydrogen sul- 
phide gas may now be passed through the acid filtrate, 
whereby any tin, tungsten, or molybdenum present will be 
precipitated as sulphide. Filter, and separate as usual. 

The filtrate was evaporated to dryness, and enough 
sulphuric acid added to expel all the hydrofluoric acid. 
The excess of acid was driven off on an iron plate, not 
over a free flame, and the oxides of columbium, tantalum, 
and titanium precipitated by boiling with a large quan- 
tity of water. The boiling must be continued for several 
hours to insure a complete precipitation, but it is not so 
difficult to bring down the metallic oxides under these 
conditions as in the bisulphate decomposition. Filter, 
and wash the oxides with hot water, first by decantation, 
then on the filter. The ignition of the oxides gave a per- 
fectly white, fine powder; and this, fused with sodium 
carbonate or potassium fluoride, yielded a colourless mass 
when cold. The oxides obtained from the bisulphate 
never did so, but formed with the carbonate a tinge of 
green, and with the fluoride a tinge of pink, showing the 
presence of manganese, and probably of iron. 

The filtrate from the mixed oxides contained iron, man- 
ganese, and uranium. These were separated by am- 
monium sulphide and ammonium carbonate, following 
the plan given under the bisulphate method. 

When the objeft is simply the extradion of pure mixed 
oxides, the above procedure may be somewhat varied. 
The fusion is made just as usual, then taken up with 
vvater insufficient for perfed solution, and a small quan- 
tity of hydrofluoric acid, boiled, and filtered. On cooling, 
the filtrate will be found to be an almost solid mass of 
the columbium double fluoride, 2KF.CbOF3.H2O, which 
separates as a beautiful shining salt and consists of thin 



laminae. At first the tantalum double fluoride remains 
undissolved, or is dissolved only in small quantity, as it 
is a very insoluble salt compared with the columbium 
compound, but if too much hydrofluoric acid is added the 
tantalum will be discovered with the columbium potas- 
sium fluoride, and larger amounts of iron and manganese 
will also contaminate it. From a very concentrated 
solution of the columbium double fluoride, such as would 
be obtained by this method, any tantalum double fluoride 
will, if present, separate almost immediately. These 
needles should be examined under a microscope for the 
thin transparent plates of the columbium salt. When 
these begin to appear filter at once and use a pump. 
The plates are a good indication that all tantalum is 
separated. The filtrate, on standing, will usually give 
the columbium salt, but it may have to be concentrated a 
little. The first crop of crystals may be coloured pink by 
manganese or iron. Re-crystallisation, however, removes 
this. The next crop is fairly pure. When working with 
large quantities a very satisfacftory approximate separation 
of columbium from tantalum may be obtained by this 
method of extradion. 

As boiling with pure water, or even with water contain- 
ing a small amount of hydrofluoric acid, decomposes the 
tantalum potassium fluoride and leaves an insoluble 
compound, 2(2KF.TaF5)Ta205, while the columbium 
double salt is praftically unafifedted, this treatment leaves 
us in the end a white, finely-divided mass which is almost 
free from columbium. By heating this residue on a water- 
bath with a rather concentrated solution of hydrofluoric 
acid and a little potassium fluoride, the tantalum potas- 
sium fluoride is obtained, and may be purified by re-crys- 
tallisation. 

The Gibbs method was used for the preparation ot 
rather large quantities of tantalum and columbium potaS' 
slum fluorides. I think it preferable to the bisulphate de- 
composition and subsequent solution of the oxides in 
hydrofluoric acid in that it does not consume so much 
time, and iron and manganese are more readily elimi- 
nated. The only objedion is that large platinum vessels 
are needed ; as a substitute for these, rubber beakers and 
funnels were sometimes used. 

The method finally adopted is as follows : — 

Separation of Columbium and Tantalum by their Potas- 
sium Double Fluorides, — The pure mixed oxides were 
placed in a platinum crucible with three times their 
weight of potassium fluoride, then moistened with hydro- 
fluoric acid as described under the decomposition of the 
mineral by the Gibbs method. By treating the fusion 
with water and hydrofluoric acid an almost perfedt solu- 
tion was obtained, since only a trace of silica was present. 
Concentration gave the long pointed needles of tantalum 
potassium fluoride, 2KF.TaF5. These were filtered and 
the solution again concentrated. The crystal crop should 
be examined under the microscope, as it may be a mix- 
ture of tantalum and columbium. Usually it is only 
tantalum. 

If a considerable excess of hydrofluoric acid and potas- 
sium fluoride is present in the mother-liquor, the next 
crop of crystals may be a complex mass about which the 
analyst can come to no definite conclusion. The fradion 
consists principally of long crystals much like the tita- 
nium double fluoride, and, to make the matter more 
puzzling, these crystals are not so soluble as those sepa- 
rating at the same time. They may be obtained pure by 
treating the mixture with a few drops of water and quickly 
filtering. Re-crystallisation from pure water gives the 
laminated salt 2KF.CbOF3.H2O. If the acid and potas- 
sium fluoride are not in large excess, usually two, and 
sometimes three, crops of the laminated salt are formed, 
but in time the long needles are almost sure to make 
their appearance. These needles were tested for tita- 
nium, but no satisfadory evidence of its presence was 
obtained. 

When the solution is very concentrated large thin 
plates separate from it. These do not give the readion 



20 



Formation oj Antimony Cinnabar. 



t CHBMiCAt, News, 
\ Jan. 8, 1897. 



with gallotannic acid, but they readl with zinc, hydro- 
chloric acid, and potassium thiocyanate. This test for 
columbium compounds will be noiiced later. Re-crys- 
tallisation does not give the laminated salt. The crystals 
are always found, and are by no means in small quantity. 
With zinc and hydrochloric acid they give a greenish 
colour which quickly becomes brown. They were re- 
peatedly re-crystallised, then decomposed with sulphuric 
acid. The oxide obtained was white, and at 19° C. had a 
specific gravity of 4'57. 

The oxide was placed in a platinum retort connedted 
with a platinum condenser; hydrofluoric acid was poured 
over it, and a free flame was applied. The volatile pro- 
dudts were colleded in water in a platinum dish. Several 
evaporations were necessary for the volatilisation of this 
oxide. The solution in the dish was then treated with a 
small quantity of potassium fluoride and concentrated. 
The same large, thin plates crystallised out. These 
crystals were very beautiful, being frequently over an inch 
in length and ij inches in width. They were so trans- 
parent that often their presence in the dish was altogether 
unnoticed. 

Analyiis. 



Substances taken. 
Grm. 

o'50OO 



K2SO4 found. 
Grm. 

0*5268 



CbjOj found, 
tirm. 

00059 



This analysis would indicate that the salt is probably 
acid potassium fluoride with a small quantity of the 
double fluoride of columbium, yet it must not be forgotten 
that the readions given above cannot be regarded as con- 
clusive evidence of the presence of columbium. 

Because of the brown colour with zinc and hydrochloric 
acid these crystals were also tested for titanium. Its 
presence could not be detected. 

(To be continued). 



FORMATION 



OF 

By J 



ON THE 

ANTIMONY 
H. LONG. 



CINNABAR. 



The composition of the pigment known as antimony 
cinnabar has been stated by several different formulae, as 
may be seen by consulting the leading hand-books of 
chemistry. The substance was usually considered as a 
mixture of sulphide and oxide or as an oxysulphide with 
the formula 862820. The formula 86283 is found also 
in some of the older works, and Baubigny (Comptes Rendus, 
Odober 22, 1894) has shown that this is undoubtedly the 
correft one. Experiments made by myself, and described 
in this Journal in February, 1895, led me to adopt the 
same formula. 

The compound is usually prepared by boiling a solu- 
tion of antimony chloride or tartrate with sodium thio- 
sulphate or crude calcium thiosulphate. As obtained 
from the acid solution of the chloride, the pro- 
dud is not pure and not of constant composition, being 
frequently mixed with oxychloride. This mixture is a 
mechanical one, and analysis made from it has no value 
in establishing a formula. The precipitate obtained by 
boiling a mixture of pure solutions of tartar emetic and 
sodium thiosulphate, on the other hand, has a constant 
composition, and numerous analyses I have made of it in 
the past year lead to the formula already given {loc. cit.). 

By analogy with other formulae established in the paper 
referred to, I suggested there that the readion between 
the tartrate and thiosulphate may be represented by this 
equation : — 

2KSb0C4H406-l-Na2S203 + H20 = 

= 2KNaC4H406-i-Sb203+H2S203, 



the oxide and thiosulphate then ading on each other to 
form sulphide : — 

8b203-t-2H2S203 = Sb2S3 + 2H20-hS02-t-50. 
The oxygen and sulphur dioxide are not liberated as 
such, but held as polythionates with the excess of thio- 
sulphate used. 

To throw further light on the readlion I have attempted 
the formation of the cinnabar by other methods. While 
the produdt is sulphide of antimony, it appears that it 
can be made with its charadteristic colour only by the 
decomposition of a tiiiosulphate. All attempts to obtain 
the true precipitate by adion of hydrogen sulphide or 
alkali sulphides and sulphur dioxide on antimony solu- 
tions failed. The only body formed was the amorphous 
sulphide, often mixed with sulphur. On the other hand, 
by the adion of a neutral or acid mixture of an antimony 
compound and a thiosulphate on each other, the cinnabar 
red produdt is the only one formed. If the mixture is 
made alkaline by the addition of a drop or two of 
ammonia water, no sulphide whatever precipitates. A 
small amount of hydraied oxide of antimony separates, 
but the decomposition of the thiosulphate is prevented. 
On the addition, now, of enough weak acid to neutralise 
the ammonia a yellow precipitate soon appears, but this 
speedily changes to deep bright red. The formation of 
the true cinnabar seems to begin by the appearance of a 
yellowish intermediate produdt, which is compatible with 
the above equations. 

In this connexion it is interesting to note the behaviour 
of pure antimony trioxide with solutions of thiosulphate. 
The readion of the latter with a soluble antimony com- 
pound is comparatively rapid, and experiments were 
made to show the adion of the oxide under the same 
conditions. It was found that the latter, when added to 
a strong or weak neutral thiosulphate solution, is unable 
to effed a decomposition in the cold or by application of 
heat. When the mixture is boiled the oxide remains 
perfedly white. This is true even after heating in an 
autoclave under a pressure of eighteen atmospheres. 

It was found, however, that with the addition of a little 
acid to the mixture of oxide and thiosulphate a readion 
followed after a time, although it never became complete. 
In a series of experiments a constant weight, 0*576 grm. 
of the pure precipitated, washed, and dried oxide was 
taken and mixed with water, and a constant weight of 
sodium thiosulphate in solution, in each case 0*992 grm. 
of the salt. Definite volumes of half normal hydrochloric 
acid were then added, and water enough to make the 
total volume 50 c.c. in each case. The mixtures were 
made in small Erlenmeyer flasks, loosely stoppered, and 
were very frequently shaken. The amounts of hydro- 
chloric taken are given in the table below. The readions 
became apparent only after several minutes, and, after 
five hours, had advanced so far in the mixtures numbered 
one and two, that the produds had become orange. 
The readions in the other flasks were less marked, but 
later became strong. The mixtures were made on 
Odober yth, and were shaken many times daily through 
two months ; in fad, as long as any change of colour in 
them was noticed. On December 3rd the amount of sul- 
phide of antimony present was found by the method of 
Rivot, oxidation by chlorine after preliminary treatment 
with strong potassium hydroxide solution. The sulphur 
is found as sulphate, and the amount of sulphide formed 
in each case is shown by the table. 

Amount BaSO, SbjO, 

No. cfSbaOg. NajSaOa. N/2HCI. HjO. found, converted. 
Grm. Grm. C.c. C.c. Grm. Grm. 

1 0*576 0992 2 48 0*155 0*064 

2 0*576 o'gga 4 46 0*293 o*i2i 

3 0-576 0992 8 42 0*384 0*158 

4 0*576 0*992 12 38 0*427 0*176 

5 0*576 0*992 16 34 0*454 o'^S? 

In mixtures one and two no evolution of sulphur dioxide 
could be deteded by the odour or by tests, but in the 



CBBUICAL MBWS, I 
Jan. 8, 1897. t 



Detection oj Caramel in Wines. 



21 



others it was apparent, weak in 3 and strong in 4 and 5. 
No free sulphur was precipitated in any case, or at any 
rate could not be found in the final produd. Although 
but a small part of the oxide was adually converted, the 
colour of the produdts in mixtures i and 2 was a deep 
cinnabar, and perfedtly charafteristic. The amounts of 
sulphide formed or of oxide converted are not proportional 
to the volumes of acid used, and are much less than 
should be found on the assumption that the readion 
begins by the produdtion of antimony chloride from the 
oxide. If this were true, the sulphide formed by means 
of the soluble thiosulphate should increase with the acid 
taken. The readlion appears to take place between the 
oxide and thiosulphuric acid liberated by the hydrochloric 
acid, as was suggested by several experiments. In one 
case 0*500 grm. of antimony oxide was treated with 
10 c.c, of half normal hydrochloric acid and 30 c.c. of 
water, as before, and allowed to stand twenty minutes, 
with frequent shaking. The mixture was then filtered, 
and to the filtrate i grm. of sodium thiosulphate in 
10 c.c. of water was added. In a short time a precipitate 
of sulphur formed, perfedlly light coloured, showing the 
absence of even a trace of the antimony. The rapidity 
with which the thiosulphate was decomposed showed 
that the hydrochloric acid taken must be in the filtrate 
and not in the residue, as oxychloride for instance. 
Titration of the filtrate showed this in a similar case. In 
a second experiment the acid and thiosulphate, in 
amounts equal to those of the last experiment, were 
mixed, and after the lapse of one minute the now 
opalescent mixture was added to some antimony oxide. 
Although the readion between the first substances had 
gone into its second stage, showing that the hydrochloric 
acid was now certainly in combination, a precipitation of 
antimony sulphide began almost immediately, and in a 
short time the cinnabar colour was distind. 

Thiosulphuric acid is usually spoken of as quite 
unstable, but Landolt has shown (^Ber.d. Chem.Ges., xvi., 
2958) that in dilute solutions it may exist many seconds, 
even minutes. The interval before precipitation is 
lengthened by dilution. If decomposition begins in pre- 
sence of compounds of the heavy metals, a sulphide, 
sulphur dioxide, and polythionates may form. A large 
excess of thiosulphuric acid is necessary to complete the 
reaftion in this manner, as suggested by the experiments 
of Vortmann {Ber. d. Chem. Ges., xxii., 2307). 

In Experiment No. i of the table above the amount of 
hydrochloric acid taken is just one-eighth of that neces- 
sary to complete this readtion with the thiosulphate : 

2HCI -h NajSzOj = 2NaCl + HjSaOg. 

By full conversion enough acid would be liberated to 
complete the equation assumed at the beginning, 

Sba03-f2HaSa03 = Sb2S3-f2H20 + S02-f50, 

with the amounts of oxide and thiosulphate taken. It 
follows, therefore, that not over one-eighth of the antimony 
oxide taken should be found converted into sulphide, and 
the result of the experiment shows slightly less than this. 
According to this theory we should have 0*072 grm. of 
oxide changed. The test shows 0-064 grm. In the 
second and following experiments the amount of oxide 
converted is relatively still less. The acid taken in the 
last experiment is sufficient to decompose all of the 
thiosulphate and thus permit the conversion of all of the 
oxide. But the result shows that slightly less than one- 
third the oxide has been changed. In the first experi- 
ment no escape of sulphur dioxide was noticed, while in 
the last it was quite marked, and this fadt has doubtless 
some connedion with the low amount of sulphide formed. 
The readlion which takes place in a weak solution of 
thiosulphuric acid is evidently different from that in the 
strong solution, inasmuch as the greater portion of the 
sulphur seems to be given off as sulphide in the one case 
and as sulphur dioxide in the other. 



In the somewhat similar readlion with arsenious oxide 
Vortmann (loc. cit.) suggests this equation— 

As203 + 9H2S203 = AsaS3-f3H2S406-H3S02-f6H20, 
in which but one-sixth of the sulphur present is used to 
form sulphide. By increasing the amount of hydrochloric 
acid added to the thiosulphate the decomposition of the 
latter is hastened. 

It is possible that after a time, with increased libera^ 
tion of sulphur dioxide, the formation of sulphide may be 
retarded, as was suggested by this experiment, I mixed 
half a grm. of the antimony oxide with one grm. of sodium 
thiosulphate in 10 c.c. of water, and added 10 c.c. of half 
normal hydrochloric acid and 30 c.c. of moderately strong 
solution of sulphur dioxide free from air. By using water 
instead of the last solution, precipitation would appear in 
a few minutes, but in this case it was delayed several 
hours, and then but a slight amount of yellowish produdl 
appeared. The thiosulphate is therefore protedted from 
decomposition by the presence of the sulphur dioxide. 

The cinnabar is easily formed from the oxychloride of 
antimony without addition of acid. Some recently pre- 
cipitated and well washed oxychloride was mixed with 
water and thiosulphate solution of the strength used 
before. The charadteristic colour soon appeared, and in 
a short time the whole produdt seemed to be cinnabar. 
The readtion is doubtless aided by the hydrochloric acid 
liberated by the decomposition of the oxychloride in pre- 
sence of water. The acid in turn attacks the thiosulphate, 
and so the process becomes continuous and rapid. These 
readlions are all much hastened by application of heat 
and the quantitative relations are also altered, but at a 
temperature of 20° C. thiosulphuric acid seems to be the 
adlive precipitating agent in the cases investigated. — 
yournal of the American Chemical Society, xviii., No. 4. 



DETECTION OF CARAMEL IN WINES. 

POSSIBLE CONFUSION WITH THE COAL-TAR 

COLOURS. 

By A. J. DA CRUZ MAGALHAES. 

Caramel is frequently employed — at least in Portugal— 
to give a fadtitious appearance of age to white liqueur 
wines. There exist methods for the recognition, and 
even for the quantitative determination, of caramel in 
wines, but we do not find in literature any indication as 
to the possible confusion between the coal-tar colours 
and those of caramel. Now this confusion may take 
place, and lead to grave errors. 

In the course of some researches on the colouring 
matter of Portuguese wines I was led to try, on a liqueur 
wine from Oporto which, as I afterwards recognised, had 
been strongly caramelised, the general readlions given 
for the detedtion of coal-tar colours. The following are 
the results : — 

1. I boiled 100 c.c. of wine for ten minutes with 10 c.c. 
of a solution of potassium sulphate and a flock of mor- 
danted wool. The wool was dyed and retained its orange- 
yellow colour after plentiful washings in water and with 
ammonia. 

2. 20 c.c. of wine were mixed with 10 c.c. lead sub- 
acetate and were filtered after agitation. The filtrate 
passed through with a distindt orange-red colour, and 
gave up its colour, on shaking, to amylic alcohol. 

3. 100 c.c. of wine, supersaturated with ammonia, and 
shaken up with amylic alcohol, gave up their orange- 
yellow colour to this solvent. 

4. 10 c.c. of wine were agitated (both in cold and in 
heat) with o'2 grm. yellow mercury oxide for one minute, 
and filtered after settling. The filtrate was coloured an 
orange-yellow in each case. 

We might therefore infer that the wine in question 



22 



Government Laboratory of Tasmania, 



f Crbuical NbwSi 

I Jan. 8, 1897. 



was coloured an orange-yellow with one or more coal-tar 
derivatives. 

I repeated the same experiments with a wine of the 
same type, of my own vintage, to which I had added pure 
caramel made with ordinary sugar. The results were ah- 
Bolutely the same. 

On operating with the same wine without the addition 
of caramel nothing similar was obtained. 

I repeated these experiments with pure caramel ; the 
results obtained were exadtly those to which I had added 
caramel. Without any doubt the colours of caramel 
may therefore be confounded with those derived from 
coal. 

To throw light on a second point of this interesting 
subjeft, I prepared caramel from dextrose and saccharose, 
both very pure. 

The two solutions of caramel thus prepared were 
treated with lead boric acetate and agitated with amylic 
alcohol. This remained colourless with dextrose caramel ; 
with saccharose caramel the alcohol took a deep orange- 
yellow. 

If both were supersaturated with ammonia and then 
shaken up with amylic alcohol, the first gave a greenish- 
yellow colour to the alcohol, and the second a very deep 
orange-yellow. 

With the former ether takes no colour, but it takes an 
orange-yellow with the latter. 

Mordanted wool took a yellow colour with the former, 
but an orange-yellow with the latter. 

Cazeneuve'stest does not alter the original colour of the 
two solutions. 

The author is continuing the researches. — CompUs 
Rendus, cxxiii., No. 21. 



that it has escaped the attention of chemists for so long 
a time ? 

The examination of the ash of bituminous and anthra- 
cite coal shows the presence of titanic oxide. The results 
of some determinations are as follows : — 



Jellico (Tenn.) bituminous coal 
Coal Creek (Tenn.) bituminous coal 
Pocahontas (Va.) bituminous coal .. 
Middlesborough (Ky.) bituminous coal 
Pennsylvania anthracite coal .. 



THE OCCURRENCE OF TITANIUM. 
By CHARLES E. WAIT, 

It is not my present purpose to repeat what has been 
already frequently published relative to the presence of 
titanium in minerals, typical rocks, meteorites, clays, 
soils, blast furnace produds, &c. I wish merely to call 
attention to the fad that some of the bodies with which 
we have much to do contain titanium, and that, probably 
owing to the difficulties formerly experienced in its esti- J 
mation, it has been more frequently overlooked than is 
generally supposed. 

In the recent examination of food materials, under the 
diredtion of the United States Department of Agricul- 
ture, I have had occasion to make analyses of the ashes 
of some plant materials, and, this having led to further 
investigations, I was interested and surprised to find 
titanium present in every piant ash thus far examined. 

This is, in fad, surprising, as it is stated by some 
writers (Roscoe and Schorlemmer) " that it does not 
appear to form part of the animal or vegetable kingdom." 

The amount of titanic oxide found in the ash of some 
vegetable material is as follows: — 

Oak wood 0-31 per cent 

Apple and pear wood (mixed) .. o'2i ,, 

Apple .. o'li „ 

Cow peas o'oi ,, 

Cottonseed meal 0*02 ,, 

From the above determinations we are reasonably safe 
in assuming that titanium is assimilated by plants. If 
this is true, it seems very strange that reference to this 
fadt has not been made by recent writers upon agricul- 
tural chemical analysis, and upon the chemistry of vege- 
table life. 

In fadt, in consulting treatises on ash analysis with 
tables (Wolff;, I do not find any mention whatever of 
the presence of titanium. If this is a fadt, can it be true 



0-69 per cent 
o"95 ., 
oy4 •* 
083 „ 

2-59 

With reference to the presence of titanic oxide in the 
ash of coal, it may be fairly assumed that, partly owing 
to the infiltration of clay and earthy materials, it would 
be found there, but is it fair to assume that its presence 
is wholly accounted for in that way ? If mention has 
been made of the presence of titanium in the ash of coal, 
it has thus far escaped my attention. 

The method employed in the above determination is 
that of A. Weller {Ber. d. Chem. Ges., 1882), which is 
based upon the fad that hydrogen peroxide, when added 
to a solution of titanium, produces a compound of an in- 
tensely yellow colour. There are precautions necessary 
in the execution of this method which have already been 
pointed out {yourn, Amer. Chem. Soc. xiii., 210.) 

It will be my pleasure to report additional notes at an 
early day concerning the presence of titanium in the vege- 
table kingdom. Valuable service has been rendered in 
the above work by Messrs. J. O, LaBach and C. O. 
Hill. — yournal of the American Chemical Society, xviii., 
p. 402. 



GOVERNMENT LABORATORY OF TASMANIA, 

By the courtesy of Mr. W. F. Ward, Assoc. Royal School 
of Mines, we have been favoured with the report of the 
Government Laboratory for the year 1895. 

There has been a falling off in the number of samples 
analysed for municipalities and private individuals, 
though the work in the latter case is largely gratuitous, 
and in the former exclusively so. On the other hand the 
work done for the Government more than compensates 
this deficiency. The increase of duty on "oils" 
imported for eight months more than defrays twice over 
the total yearly cost of the laboratory. The departments 
of mines, railways, police, health, and agriculture obtain 
more or less analytical work free of cost. On the other 
hand. Customs' duties have to be paid even on the 
chemicals imported for the use of the laboratory. So 
that this department is much more than self-supporting. 

The total number of samples analysed in the Govern- 
ment laboratories during the year 1895 was 2197, 1550. 
of which were teas, 12 of which were found adulterated 
or defedive. Only one sample of coffee was examined 
and condemned as consisting one half of chicory. Seven 
samples of spirit of wine tested for the Customs were not 
sufficiently methylated, i.e., not made undrinkabie. On 
this we may remark that we have known methylic 
alcohol (not methylated spirits) be drunk to a serious 
extent by men engaged in dye and colour works. It does 
not appear that Tasmania has adopted the absurdity of 
requiring an addition of mineral " naphtha " to methyl- 
ated spirits. The Tasmanian fiscal authorities, as well 
as those in the Home Kingdoms, should awake to the 
faft that a minimum of Dippel's animal oil renders 
alcohol undrinkabie without interfering with its technical 
uses. 

Nineteen samples of water have been analysed. The 
composition of two may, it is hoped, prove exceptional. 
One of them contained 0"98 part of albumenoid ammonia 
per million of water, as well as i'3 grains per gallon of 
chlorine. Another contained 97 grs. per gallon of 
chlorine. Much of this was in the state of magnesium 



Chbuical News. 
Jan. 8, 1897. 



Academic des Sciences. 



23 



chloride. The water was taken from the premises of a 
milk-vendor. Quackery flourishes in the Colonies as well 
as in the Home Kingdoms. A " self-cure " for nervous 
debility, advertised and sold at one guinea per ounce, was 
found to be merely Peruvian bark in powder, the present 
retail price per ounce being about one shilling ! 

A fatal case of poisoning with strychnine is cited. 
Thirty-six grs. of the poison were separated from the 
contents of the sugar basin. There is also mention of 
wholesale malicious poisoning in Queensland. There is 
no mention of poisoning with any substance unknown to 
European pharmacologists. In this direction much 
work remains to be done, and much of it might be done 
by local analysts. 

It will not be deemed an unpardonable digression if we 
mention that malicious poisoning — as we learn from 
private sources — is exceedingly rife in South Africa. The 
deadly drug, or drugs, are introduced into the victim in 
the state of snuff, of which the Kaffirs are passionately 
fond. But they will now rarely accept a pinch from a 
stranger without careful scrutiny. To return to Mr. 
Ward's report, a number of samples of ores and tailings 
have been examined for the Secretary of Mines. In addi- 
tion to gold and silver, nickel, cobalt, copper, tin, anti- 
mony, bismuth, zinc, and lead have been determined. 
We find no mention of platinum. A sample from 
M. Dundas contained silver at the rate of 1*057 °2S. per 
ton, and gold specimens gave 60 to 63 ozs. Arsenical 
pyrites are found, and prove a source of great annoyance. 



PROCEEDINGS OF SOCIETIES. 



ACADEMIE DES SCIENCES. 

At the meeting of the Academie des Sciences, on Mon- 
day, Dec. 2ist, M. A. CoRNU delivered the following Pre- 
sidential Address: — 

When Lavoisier, Schwann, and Cagniard Latour 
studied the fermentation of beer, and Pasteur, taking 
up the question, patiently followed the development 
of those microscopic beings in generations called spon- 
taneous in the diseases of wine or of silk-worms, who 
could have foreseen that a day would come when this 
admirable research would have so important a bearing 
on the welfare of humanity, demonstrating that these 
infinitely minute beings rank among the most important 
fadlors of human life. Pasteur, in his long and fruitful 
career, has taught us that it is possible to specify these 
organisms — to combat and even to diredl them, accord- 
ing as they are our allies or our enemies. They have the 
power of conferring immunity or of conducing us in- 
fallibly to death. 

The public see only final success; they mostly ignore 
the starting point of such researches ; they ignore the 
efforts and the perseverance required to lead to what is 
vulgarly called a pradlical discovery ; they are even prone 
to disdain abstradt science, and to estimate the merit of 
the savant by the immediate market value of his dis- 
coveries. 

Utilitarianism is, in faft, one of the maladies of the 
present age, perhaps one of the gravest, because it tends 
to crush the upward flight of the human spirit, and to 
fetter it to the exclusive worship of material interests. 

Prof. Rontgen's discovery of the X rays has been, both 
for the public and for savants, the scientific event of the 
year. The speaker gave a luminous summary of the 
researches which have led to this discovery, laying due 
emphasis on the " brilliant experiments " of Mr. Crookes. 
The Rontgen rays are spoken of as a fresh benefit to be 
placed to the credit of pure science. After touching on 
the merit of the illustrious savants recently lost to the 
Academy and to science, the speaker mentioned that this 



year the Arago medal has been conferred in duplicate on 
M. Antoine d'Abbadie and on Prof. Sir W. Thompson, 
now known as Lord Kelvin. He on a recent occasion 
had pronounced France as the alma mater of his sci- 
entific youth. It is added that modern nations, though 
bent under the yoke of material interests, and crushed 
under the treacherous law of iron and blood, are still 
able on great occasions to raise their eyes to the serene 
regions above hatred and envy and to join in celebrating 
the great men whose labours increase the common patri- 
mony of intelligence at the same time as the well-being 
of mankind. 



NOTICES OF BOOKS. 



The Practical Methods of Organic Chemistry. By 
LuDWiG Gatterman, Ph.D., Extraordinary Professor 
in the University of Heidelberg, with numerous illus- 
trations, translated by William Shober, Ph.D., 
Instructor in Organic Chemistry in the Lehigh 
University. Authorised translation. New York: The 
Macmillan Company. London: Macmillan and Co., 
Ltd. 1896. Pp. 329. 

We have here an excellent work written in German, 
translated by an American, and printed in America. The 
language and the orthography employed are not in ail 
cases idiomatic English as written and spoken on this 
side of the Atlantic. Thus we find magenta invariably 
designated by the term " fuchsine." 

In the first or general part we have instrudions for. 
necessary operations, well thought out and clearly 
described. We may call particular attention to the 
direaions for fraftional distillation, to the management of 
autoclaves, and distillation at reduced pressures. 

Next follow the methods for ultimate organic analysis, 
the determination of nitrogen being performed exclusively 
by the method of Dumas. 

We now come to the special part; the performance of 
synthetical operations in the aliphatic, aromatic, pyridine, 
and quinolene series. Lastly comes an inorgaiiic part, 
viz., instrudions for obtaining in a state of purity sub- 
stances required as reagents in organic research. It vfill 
be at once observed that the author does not give a series 
of recipes. He described representative reaiStions, e.g., 
the nitration of a hydro-carbon, the redudlion of a nitro- 
compound to an amine, the redudtion of a nitro-compound 
to an azoxy-azo or hydrazo compound. The student 
who has carefully worked out these diredtions in the 
laboratory will find himself prepared for entering upon 
the wide fields of organic research without losing his 
way. One who has made no such preparation is in danger 
of " messing about " at random, and if he comes upon 
something valuable may not recognise what he has done. 

We therefore strongly recommend the careful study of 
this work, regretting only that the distinguished pub- 
lishers have not seen their way to having the English 
translation executed by an Englishman and brought out 
in England. 

Catalogue of Chemical Apparatus, Balances, Drying. 
Ovens, Furnaces, Laboratory Stands, dfc, also special 
and general Glass Apparatus, Hydrometers, Thermo- 
meters, Porcelain and Clay Ware, Jena Laboratory 
Glass Ware, and Glass Tubing. A. Gallenkamp and 
Co., 2, 4, and 6, Cross Street, Finsbury, E.C. 1896. 

An important feature in this catalogue is the special 
description of Jena laboratory glass. This ware, we are 
told, surpasses the best Bohemian glass, Kavalier's make, 
in its insolubility in water, whether at ordinary tempera- 
ture or at 80°. On treatment with caustic soda it is 



24 



Chemical Notices Jrom Foreign Sources. 



I Cbbmical Nbws, 
I Jan. 8. 1897. 



slightly inferior to Bohemian glass, but it has the 
superiority as regards resistance to sodium carbonate. 
The Jena glass has a great power of resisting sudden 
changes of temperature. Medium sized flasks, containing 
boiling toluidin (200°), bear immersion in cold water. 
Jena laboratory glass can be heated over a Bunsen flame 
without wire gauze. 

Evaporating basins are catalogued of Berlin, Thiiringen, 
and Meissen porcelain, as well as of aluminium and 
enamelled steel, of pure nickel, platinum, silver, and 
platinum gold for melting potash. There is mention of 
autoclaves for bearing a pressure of 50 atmospheres, and 
apparatus for boiling in a vacuum or at a reduced pres- 
sure. Fletcher's devices for the produdlion and distribu- 
tion of heat are quoted in great variety. Apparatus for 
pradlical distillation as devised by Hempel, Linneman, 
Glinsky, and others, are also quoted and shown. 

Of filter-pumps there is also good variety, of the con- 
strudtions of Fischer, Bunsen, Volhard, Finkener, Geissler, 
Alvergniart, and others, as also filtering apparatus in 
conjunftion with pumps. 

Various kinds of filter paper are quoted, some of which 
retain such precipitates as zinc sulphide. 

The balances and weights described are those of 
Sartorius, Becker, Verbeck and Peckholdt, and Bertnger. 

Baderiological apparatus is figured and described at 
great length. 

Spedtroscopes figure here at length unusual in cata- 
logues of laboratory requisites. Catalogues of microscopes, 
including the renowned instruments of Zeiss, will, it is 
said, be supplied on application. 

Of chemicals we find only a list of standard solution. 
Experimentalists may often find here some newly devised 
Apparatus which will prove exceedingly useful. We 
cannot help expressing our regret that Messrs. Gallen- 
kamp find themselves unable to get their printing done in 
Britain. 



Assistant Wanted in a London Laboratory. — 
Full particulars to Box M., Chemical News Office, Boy Court, 
Ludgate Hill, London, E.G. 

Chemical Student, who has been a pupil for 
the last year and a half in well-known Agricultural Labora- 
tory, bnd previously at the Royal College of Science, seeks employ- 
ment. — Address, S., 29, Park Hill, Clapham. 



Chemist, Analytical and Research, and 
Badteriologist, desires Appointment as Assistant to Public 
Analyst, with a view to ultimate Succession or Partnership. Many 
years' experience in Public Analytical Chemistry and Toxicology. 
Experienced in correspondence and in framing reports. Highest 
references if desired. — Address, " Partner," Chemical News Office, 
Boy Court, Ludgate Hill, London, E.G. 

Gentleman (27), French, desires Situation as 
chemist or Assistant. Six years' experience in Paris, two in 
London. Good Analyst, Assayer, and Ete(5tro-Chemist ; well up in 
the extradtion of metals by eleftric process, principally Gold. — Ad- 
dress, C. H. G., 19, Berwick Street, Oxford Street, W. 

Gentleman of much experience in Chemistry, 
accustomed to the control of men, and speaking French, 
German, and English, seeks position of trust in Manufa(5lory or in 
Chemical Laboratory. — Apply to Ackermann, Mining Engineer 
(Civil), of the Mining School of Paris, 132, Alderney Street, S.W. 



CHEMICAL 



NOTICES FROM 
SOURCES. 



FOREIGN 



Revue Universelle des Mines et de la Metallurgie. 
Series 3, Vol. xxxv.. No. 2. 
Uses of Acetylene.— R. K. Duncan proposes to set 
out from acetylene to form, either by way of polymeri- 
sation of benzene, CeHe, whence there may be obtained 
the innumerable series of aromaticcompounds, or ethylene 
by the adlion of nascent H. Acetylene, on account of 
its endothermic charader and its explosive properties, 
cannot compete with coal gas or eleftricity for the light- 
ing of cities. This compound was first met with by 
Davy in 1836, and described in full by Borchen in 1891. 
It yields per kilo. 280—300 litres of acetylene gas. Acety- 
lene is less poisonous than ordinary coal gas. Its lia- 
bility to explosion is a serious obstacle to its use on the 
large scale. 

Action of Coal Gas upon Caoutchouc— Goss- 
heintz.— Black tubing is the least suitable, then the red 
quality, but the grey kind is the best. 

Treatment of Rich Iron Ores and Use of Acid 
Slags.— Franz Biittgesbach.— The author has made use 
of ores containing 68 to 70 per cent of iron, with the 
addition of sufficient slags free from iron to such an 
extent that the slag may reach at least 25 per cent of the 
cast metal. 

Series 3, Vol. xxxv., No. 3. 
Copper Industry in Japan.— Japan now occupies the 
fourth rank among the copper-yielding countries-! In 
1892 it produced 20,000 tons of copper. The ore is dis- 
tributed over the entire country. The yield will soon 
exceed that of Chili. 



WEST-END LABORATORY 

FOR 

CHEMICAL & BACTERIOLOGICAL INVESTIGATIONS, 
55, WEYMOUTH STRE ET, LONDON, W. 

Chemists in all branches desirous of Laboratory Accommodation 
for Private Pra<5tice or Research, with Attendance, Reagents, andlill 
facilities, should apply lor terms to the Secretary. Courses of 'ja- 
strudlion are also given. Teiegravts: " Phagocyte, London." " 

FOREIGN SCIENTIFIC BOOKS. 

^wixjIjI^^hvcs & isro:Ra-.A.TEi 

IMPORTERS OF FOREIGN BOOKS, 

Receive regularly all Foreign Scientific Books. 

Catalogues and lists post free on application. 

14, Henrietta Street, Covent Garden, London ; 

20, South Frederick Street, Edinburgh; 

and 7, Broad Street, Oxford. 



Mr. J. G. LORRAIN, M.I.E.E., M.I.M.E, M.S.C.I., 

Fellow of the Chartered Institute 0/ Patent Agents, 

Norfolk House, Norfolk Street, London, W.C. 

" PATENTEE'S HANDBOOK " Post Feee on application. 




OLD PLATINUM 

In any form Purchased for Cash. 

Highest prices allowed by 
ROBERT PRINGLE & CO., Gold and Silver 
KeiinerB, &c., 40 and 42, Cleri^enweil Rd,, £.C. 

Send for Price List. 
Photographic Residues reduced and purchased.- 

RED-WOOD LAKES 

Free from Aniline, 
as Crimson Lake, Cochineal Red, Purple Lake, &c., 

Supplied as a SPECIALITY by 
Dr. BODENSTEIN and KAESTNER, 

Red-Colour Manufa<5turers, 

{Established 1840), 

SAALFELD-ON-SAALE, GERMANY. 

SILICATES OF SODA and POTASH. 

In the state of Soluble Glass or in concentrated solution. 
FULL STRENGTH GUARANTEED. 

OLDEST AND MOST RELIABLE MAKE. 

Supplied on best terms by 
WILLIAM GOSSAGE & SONS, Ltd., Soap Works, Widnes. 
London Agents— COSTE & CO., 18 & 19, Water Lane Tower 
Street, E.C., who hold stock, ready for delivery. 



Crbuical News,) 
an. IS. 1897. I 



Optical Analysis oj Urine, 



25 



THE CHEMICAL NEWS 



Vol. LXXV., No. 1938. 



A RAPID DETERMINATION 

OF THE 

EQUIVALENT OF SULPHURIC ACID AND ITS 

PLACE IN THE TEACHING OF CHEMISTRY. 

By WILLIAM ACKROYD, F.I.O. 

The quantitative experiments on neutralisation usually 
given to elementary students are few in number, and of 
one type ; the following variation is suggested as part of 
a scheme of quantitative work. 

a c.c. of aqueous sulphuric acid are found to be neu- 
tralised by b c.c. of solution of sodium hydroxide. 

To a c.c. of the acid a weighed quantity of magnesium 
is added (from o-i to 0*2 grm.), and when all atftion has 
ceased b c.c. of the alkali are added. The indicator 
used (methyl orange) shows that all the free acid has 
been neutralised, and it may readily be proved that all 
the metal is precipitated as hydroxide. Now run in, 
from the burette, sulphuric acid of known strength until 
the magnesium hydroxide is exaiftly neutralised. 

From the data obtained calculate the equivalent of sul- 
phuric acid. 

£^n[M»/>/^.— Strength of sulphuric acid used, 0-04945 
grm. per c.c. 20 c.c, of the acid requires 21-5 c.c. of 
alkali for neutralisation, o 146 grm. of magnesium is 
dissolved in 20 c.c. of the acid, and after addition of the 
necessary 21*5 c.c. of alkali i2'4 c.c. of the acid are re- 
quired to neutralise the magnesium hydroxide. Whence, 
taking 12 to be the magnesium equivalent, we get— 
I2"4X 0*04945x12 

o'i46 ^ ^ 

Other students obtained the numbers 49*9, 497, 487 
&c., and the figures give some idea of the degree of 
accuracy to be expeded under ordinary circumstances. 
The time taken for the estimation is much under an 
hour. 

By neutralising the magnesium hydroxide with hydro- 
chloric acid of known strength, the equivalent of this acid 
may be similarly ascertained. Results within- a unit of 
the accepted number are readily obtained. 

A recent alteration of the syllabus of the Science and 
Art Department has introduced the salutary course of 
taking quantitative work from the commencement instead 
of leaving it until the student's third year. These first 
efforts are necessarily only, in many cases, rough ap- 
proximations, but they serve to familiarise the worker 
with the laws of combination in definite and reciprocal 
proportions, equivalents, &c. The methods to be em- 
ployed, and their order, are left to the discretion of the 
teacher, who has the help of such excellent little works 
as those of Ramsay, Reynolds, and Tilden. 

I take it that in an ideal course for the elementary 
student each quantitative experiment ought to be pre- 
ceded by the qualitative work necessary for its compre- 
hension, and it ought to require as little time as possible 
for its performance, so that it can be tried often ; the 
experiments ought to follow one another in logical order, 
each one more or less built on those going before, with 
the continuity found in a series of geometrical problems, 
and collateral work in theory and practice should proceed 
abreast with them. 

The determination of equivalents will form the back- 
bone of the work, and magnesium, because of its purity 
and rapidity of aftion, lends itself admirably for the pur- 
pose, as in the following experiments : — 



1. Determination of the magnesium equivalent by find- 
ing what weight of it is required to liberate ii'l6 litres 
of hydrogen at normal temperature and pressure, i.e., 
I grm. from sulphuric acid. 

2. Determination of the oxygen equivalent by finding 
how much of it combines with 12 grms. of magnesium 
in the course of ignition of the latter in a porcelain 
crucible. 

3. Determination of the sulphuric and hydrochloric 
acid equivalents by finding what weight of each is re- 
quired to neutralise the hydroxide formed from I2 parts 
by weight of magnesium. 

4. Determination of the equivalent of caustic soda by 
finding what weight of it neutralises an equivalent of sul- 
phuric acid. 

In this order, where each experiment is based on a pre- 
ceding one, the equivalents i (assumed), 12, 8, 49, 36*5, 
and 40, would be obtained for H, Mg, O, H2SO4, HCI, 
and NaOH respedively, and each experiment is typical 
of others which will suggest themselves to the teacher. 
I think it is of importance to stick to the unit weight 
of hydrogen for comparisons, as subsequently there is 
nothing to unlearn. Where many units of other ele- 
ments are employed in empirical comparisons, as, e.g.^ 
the ratio i : 0*66 in experiment 2, instead of 12 : 8, much 
confusion arises in many minds, and the ratio 12 : 8 is 
equally available as an example of combination in fixity 
of proportions. 

It appears therefore inadvisable to follow the historic 
order in this respeft with elementary students, however 
interesting it may be when they have a better grasp of 
the subjei^t. 



OPTICAL ANALYSIS OF URINE AND 
EXACT DETERMINATION OF THE PROTEIDS, 

THE GLUCOSIDES, AND THE 

NON-FERMENTIBLE SACCHAROID MATTERS. 

By F. LANDOLPH. 

I. Sugar in Urine. — Normal healthy urine always con- 
tains from 001 to o*20 grm. sugar per litre; the exaA 
determination can only be effedled by fermentation. Set- 
ting out from 0*40 grm. of sugar per litre, the physician 
should turn his attention to the slow and progressive 
development of diabetes, which may be considered 
established when 2 grms. per litre of fermentible sugar 
is found. There are only pathological urines contain- 
ing albumen, pus, &c., which often contain no trace of 
sugar. 

2. Optical Determination of Sugar, — The saccharimeter 
is generally incompetent to demonstrate the presence of 
I grm. to 2 grms. sugar per litre, because normal urine 
always defleds from 1° to 3° to the left. It is only on 
setting out from 2° to 3° deviation to the right that we 
are almost certain of the presence of sugar in the urine, 
and it is only beyond 10 grms. per litre that the dia- 
betometer gives us fairly exacft results ; the more ex&€t 
the higher the quantity. Hence, to obtain results be- 
yond dispute, it is indispensable to have recourse to fer- 
mentation, whilst for quantities above 20 grms. per litre 
the two methods give approximately the same results. 

3. Direct Coefficient and Indirect Coefficients of Re- 
duction. — The direft coefficient of redudion can only be 
obtained with urine boiled and filtered, because raw urine 
in treatment with the cupopotassic liquid always holds a 
certain quantity of cuprous oxide in solution. To 10 c.C. 
of urine boiled and filtered we use 10 c.c. water and 
40 c.c. of Fehling's solution. We heat the mixture to 
ebullition, and keep it up, when once the readtion has 
commenced (which generally requires from three to five 
minutes), for twenty minutes ; we filter, wash the cuprous 
oxide with boiling water, dry, and ignite. The weight 
of copper oxide obtained, calculated per thousand, gives 



25 



Separation of Manganese from Tungstic Acid. 



CbbmicalNbws 
Jan. 15, i8q7. 



the direct coefficient of reduftion; the third of this 
weight gives fairly well the quantity of non-fermentible 
saccharoid matter in a litre of urine, deducing the quan- 
tity of oxide corresponding to the fermentible sugar and 
the quantity of oxide corresponding to the uric acid, of 
which one part is approximately equal to four parts of 
copper oxide. 

A quantity of non-fermentible saccharoid matter ex- 
ceeding 3 grms. per litre is the certain sign forerunning 
diabetes. Further, for these salts of urine with strongly 
diabetic disposition the duration of the introduiSion of the 
reaAion often does not exceed half a minute. 

To obtain the indirect coefficients of redudlion, we first 
split up (at first in raw urine, and then in a portion boiled 
and filtered), the mucine and analogous proteids, as well 
as the glucosides of mineral acids. We then fix in the 
urine thus treated, filtered, and adjusted to their primi- 
tive volume, the coefficients of redudlion as for the de- 
termination of the dired coefficient of redudtion. The 
difference between the figures of the two indiredl co- 
efficients gives the quantity of mucine in copper oxide, 
and the difference between the diredt coefficient of the 
boiled and filtered urine and the indiredt coefficient of 
the same urine boiled and filtered gives the quantity of 
the glucosides in copper oxide, the third part of which 
represents the weight of these compounds. 

4. Polaristrobometric Examination of Urine. — When a 
urine contains pus and analogous pathogenic elements, 
the defleiStion to the left in the very sensitive polaristro- 
bometer of P5ster and Streit becomes stronger, reaching 
5°, and even 8^ which is evidently due to the polarising 
force of the nuclei of the granulated leucocytes of pus. 
In this case it even happens that the field of vision be- 
comes totally obscure in an extent of some degrees. 
This faft is especially very important when the cellules 
and pus granules have already disappeared under the 
microscope, since this procedure alone permits us to 
know if there has been an anterior presence of pathogenic 
elements or not. 

Analogous studies are pursued to recognise and de- 
termine the nitrogenous organic compounds preceding 
aWiViminwxiA.—ComptesRendus, cxxiii., No. 26. 



THE SEPARATION OF VANADIUM FROM 

ARSENIC. 

By CHARLES FIELD and EDGAR F. SMITH. 

As vanadium and arsenic occur associated in minerals 
and likewise in artificial products, their separation becomes 
a matter of consequence. 

The course usually pursued in carrying out this sepa- 
ration is that long since recommended for the removal of 
vanadic acid from its solutions ; namely, its precipitation 
as ammonium metavanadate. Other methods have 
recently appeared in the literature bearing on analysis. 
Reference is here made especially to the publication of 
Fischer (" Bestimmung von Vanadinsaure," Dissertation, 
Rostock, 1894). 

Experiments made in this laboratory on the behaviour 
of vanadates (Journ. Am, Chem. Soc, xvi., 578) and 
arsenates (Ibid., xvii., 682) heated in an atmosphere of 
hydrochloric acid gas, in which both acids were volatilised, 
suggested the thought that if the sulphides of vanadium 
and arsenic were exposed to the same vapours perhaps 
they would show a variation in deportment. And so it 
has proved. Perfedly dry arsenic trisulphide, previously 
washed with alcohol, carbon disulphide, and ether, then 
dried at 100° C, when exposed in a porcelain boat, placed 
in a combustion tube, was almost completely expelled 
from the retaining vessel at the ordinary temperature. 
The last traces were driven out at a temperature little 
above 150° C. Brown vanadium sulphide, in a perfeAly 
dry condition, treated in the same manner, was not ' 



altered. It only remained then to prepare mixtures of 
known amounts of the two sulphides and subjeft them to 
the adtion of the acid vapour. To this end the following 
experiments were made: — 

I. — 0*1303 grm. of vanadium sulphide, 
0"i302 grm. of arsenic sulphide. 
The arsenic sulphide was volatilised without difficulty 
and left o'i2g7 grm. of vanadium sulphide. 

II. — 0-1290 grm. of vanadium sulphide, 
0*2242 grm. of arsenic sulphide, 
gave after exposure of one hour to hydrochloric acid 
vapour a residue of vanadium sulphide, weighing 0*1297 
grm. 

III. — 0*0828 grm. of vanadium sulphide, 
0*0582 grm. of arsenic sulphide, 
left 0*0827 grm. of vanadium sulphide. 

IV. — 0*1306 grm. of vanadium sulphide, 
0*2028 grm. of arsenic sulphide, 
gave a residue of 0*1308 grm, of vanadium sulphide. 
V. — 0*1403 grm. of vanadium sulphide, 
0*2409 grm. of arsenic sulphide, 
left 0*1404 grm. of vanadium sulphide. 

The temperature in these experiments was not allowed 
to exceed 250° C, as beyond that point there is danger 
of affedting the vanadium and causing its partial volatili< 
sation. 

The method worked so well and with such evidently 
favourable results that the following course was adopted 
in the analysis of a specimen of the mineral vanadinite. 
0*2500 grm. of air-dried and finely divided material was 
placed in a porcelain boat ; the latter was then introduced 
into a combustion tube and gently heated in a current of 
dry hydrochloric acid gas. By this treatment vanadic 
and arsenic oxides were expelled, leaving lead phosphate 
and chloride. The receiver containing the vanadium 
and arsenic was made alkaline and digested with ammo- 
nium sulphide. From the solution of the sulpho-salts the 
vanadium and arsenic sulphides were set free by a dilute 
acid. After washing and careful drying these sulphides 
were separated as indicated in the preceding lines, then 
changed to oxides and determined in the usual manner. 
The sum of the total constituents determined as lead 
oxide, phosphoric oxide, vanadic and arsenic oxides, with 
some lead chloride, amounted to 0*2501 grm. 

The method, in addition to being satisfactory in the 
analytical way, certainly forms a very excellent means of 
purifying and freeing vanadium from arsenic. — journal of 
the American Chemical Society, xviii.. No. 12. 



THE SEPARATION OF MANGANESE FROM 

TUNGSTIC ACID. 

By WALTER T. TAGGART and EDGAR F. SMITH. 

The necessity of obtaining pure tungstic acid from time 
to time, using wolframite as the starting out material, 
has frequently suggested the inquiry as to what course 
would probably prove the best in the quantitative separa- 
tion of this acid from oxides, such as those of iron and 
manganese. 

In the experiments recorded in this communication only 
the results obtained from a study of mixtures of a man- 
ganous salt and a soluble alkali tungstate will be given. 
The diredions taken in the experimentation were, ist, to 
effe(ft the separation by the use of yellow ammonium sul- 
phide in the presence of ammonium chloride ; 2nd, to 
eliminate the acid oxide by the use of an alkaline car- 
bonate. 

Following the first course, mixtures of definite amounts 
of ammonium tungstate and manganous chloride were 
made. To these was added water and a considerable 



CRBMiCAL News, I 
Jan. 15, 1897. I 



Separation of Bismuth from Lead, 



27 



excess of yellow ammonium sulphide, together with 
ammonium chloride. The mixtures were digested on a 
water-bath at 70° C. for several hours, and the vessels 
containing them were then closed and allowed to stand 
during the night. The manganese sulphide was filtered 
out, and, after solution, was changed into sulphate and 
weighed as such, or it was finally obtained as protosesqui- 
oxide in the customary way. 

Results, 
Manganous oxide Manganous oxide 

present. found. 

Grm. Grin. 

O'igso o'2i2l 

o'ig49 0*2255 

o'tzQO o'lyoS 

o'i287 0*1720 

0*1291 0*1760 

In every trial tungstic acid adhered to the metallic 
oxide. 

In trying the second suggestion the soluble tungstate 
and the soluble manganous salt were digested for some 
hours in a platinum dish, upon a water-bath, with an 
excess of a 10 per cent potassium carbonate solution, 
after which the whole was evaporated to dryness, the 
residue boiled up with water, the manganous carbonate 
filtered out, washed, and finally converted into protoses- 
quioxide. 

Results 

Manganous oxide Manganous oxide 

present. found. 

Grm. Grm. 

0*1949 0*1516 

0*1949 0*1534 

Several trials were made using a 50 per cent solution o^ 
potassium carbonate. 

Results. 

Manganous oxide Manganous oxide 

present. found. 

Grm. Grm. 

0*1951 0*1745 

0*1950 01528 

The experimental evidence given in the preceding 
paragraphs leaves no doubt as to the insufficiency of the 
two methods which were tried in effedling the desired 
separation. It is probable that fusion with an alkaline 
carbonate will alone answer for this purpose. How com- 
plete that course would be can only be ascertained by 
careful experimentation. 

In the course of analysis molybdenum is quite often 
obtained as sulphide. Its conversion into a weighable 
form is attended with more or less difficulty. Trials made 
in connexion with its estimation show that if the sul- 
phide, as generally obtained, be dried, then intimately 
mixed with anhydrous oxalic acid, its careful ignition to 
trioxide can be made quite rapidly. 

Results. 

Molybdenum trioxide Molybdenum trioxide 

taken. found. 

Grm. Grm. 

0*3000 0*3009 

0*3000 0*2990 

0*1007 0*1011 

— journal of the American Chemical Society, xviiit, No. 12* 



On Dibromo 1—3 Propene. — R. Lospieau. — Epi- 
dibromhydrine, /3: CHBr=CH-CH2Br, is a colourless 
liquid which irritates the eyes and the skin. Its density 
at 0° is 2-097. If cooled to -75° it congeals, but after- 
wards melts at -52°. It boils at 155— 156°. Its mole- 
ciilar weight is '=200°.— Contptes Rendus, cxxiii., No. 25. 



THE SEPARATION OF BISMUTH FROM LEAD. 
By ARTHUR L. BENKERT and EDGAR F. SMITH. 

Many methods have been suggested to effedt this separa- 
tion. In a recent issue of the Zeiischrift fiiir Angewandte 
Chemie (1895, P- 53o)i O'av Steen reviews thirteen of 
these methods, and concludes that an early proposal of 
Rose {Ann. Chem. Phys. Pogg., ex., 425), in which the 
lead is thrown out as chloride and weighed as sulphate, 
another by Lowe {yourn. Prakt. Chem., Ixxiv., 348), in 
which the bismuth is removed as basic nitrate, and a late 
suggestion^made by Jannasch (Ber. Chem. Ges., xxv., 124), 
viz., the expulsion of the bismuth as bromide from a 
mixture of lead and bismuth sulphides by an air current 
carrying bromine, are the most satisfadlory. At least these 
methods gave Steen the best results. The separation of 
bismuth from lead frequently confronts the analyst, and 
any novelty in this diredion cannot be absolutely devoid 
of interest; hence the present communication, which 
brings data that may perhaps prove of service in the 
hands of others who are interested in the solution of this 
analytical problem. 

It will be recalled that Herzog (Ztschr. Anal. Chem., 
xxvii., 650) proposed to separate bismuth from lead by 
precipitating the former as basic acetate. The method 
required considerable time for execution, and in other 
hands than those of its author apparently has not yielded 
entirely satisfadory results. 

An idea closely related to that of Herzog would be the 
substitution of a formate solution for that of the acetate. 
This was done, with results that are very interesting. 

Solutions of lead nitrate and bismuth nitrate in nitric 
acid were made up of such strength that 20 c.c. of the 
first contained 0*2076 grm. of lead oxide, and 20 c.c. of 
the second 0*1800 grm. of bismuth trioxide. The lead 
and bismuth were accurately determined after dilution to 
a litre. 20 c.c. of these two nitrate solutions were then 
introduced into a beaker glass, carefully diluted and 
almost neutralised with sodium carbonate, or until the 
incipient precipitate dissolved slowly, when considerable 
sodium formate solution of sp. gr. 1*084 and a few drops 
of aqueous formic acid were added. The total dilution 
of the liquid was 250 c.c. It was gradually heated to 
boiling and held at that point for five minutes. The pre- 
cipitate was then allowed to subside, but was filtered 
while yet hot. The basic formate separates rapidly, and 
is easily washed if not boiled too long. It was washed 
with hot water, then dissolved in dilute nitric acid, and 
precipitated with ammonium carbonate. The ignited 
bismuth trioxide weighed too much ; it contained lead. 
However, the impure oxide was dissolved in nitric acid, 
diluted to 250 c.c, and after the addition of sodium car- 
bonate to almost complete neutralisation, sodium formate 
and free formic acid were added as before, and the pre- 
cipitation of basic formate repeated. This precipitate 
after solution and the bismuth thrown out by ammonium 
carbonate, gave 0*1804 grm. of bismuth oxide instead of 
o*i8oo grm. as required by theory. Seven additional 
separations, in which the quantities of bismuth and lead 
were the same as indicated above, gave — 

o*i8o6 grm. of BijOs. 
0*1806 ,, „ 
0*1803 •> » 

0*1804 M II 

0*1804 „ „ 
01805 „ „ 
0*1796 „ „ 

The conditions in these determinations were similar to 
those previously outlined. 

With a solution containing 0*3600 grm. of bismuth 
oxide and 0*2076 grm. of lead oxide, operating in an 
analogous manner, two results were obtained ; — 
o'3595 grm. of BizOj. 
0-3605 
nstead of the required 0*3600 grm. 



28 



Determination of Atomic Masses by the Electrolytic Method, {*'""'"|',8"77'' 



The residual bismuth trioxide was examined for lead, 
but none was found. — journal of the American Chemical 
Society, xviii., No. 12. 



DETERMINATION OF THE ATOMIC MASSES 

OF SILVER, MERCURY, AND CADMIUM, 

BY THE ELECTROLYTIC METHOD.* 

By WILLETT LEPLEY HARDIN. 

Introduction. 
A GLANCE at the literature on the determinations of the 
atomic masses of silver, cadmium, and mercury, will show 
that, with the exception of cadmium, the eleiSrolytic 
method has not been tried. Aside from the fadt that cer- 
tain errors involved in the washing and drying of the 
precipitates are eliminated by this method, its simplicity 
at once gives it preference over the usual methods of 
gravimetric determinations. Inasmuch as these three 
metals are completely precipitated from certain of their 
solutions by the eledtric current, and as it is desirable to 
determine the atomic mass of any element by different 
methods, it was thought advisable to apply this method 
in a re-determination of the atomic masses of these 
elements. 

General Considerations, 

Before taking up the different metals separately, the 
following general considerations may be mentioned : — 

1. A careful preliminary study was made in the selec- 
tion of compounds. Some compounds, which from a 
theoretical standpoint seemed to offer certain advantages, 
were found by experiment not to meet the requirements 
of exaft determinations. Salts which can be sublimed 
were used whenever possible ; and in all cases only those 
salts were used which form well-defined crystals. 

2. All reagents used were either prepared or purified by 
myself, and carefully tested for impurities. 

3. The metals were deposited in platinum dishes of 
about 200 c.c. capacity and about 65 grms. in weight. 
When the precipitation was complete, before interrupting 
the current, the solution was syphoned from the platinum 
dish, pure water being added at the same time : this was 
continued until the solvent used was completely removed 
from the dish. The current was then interrupted, and the 
deposit washed several times with boiling water, with the 
hope of removing any occluded hydrogen. After drying, 
the dishes were placed in a vacuum desiccator over anhy- 
drous calcium chloride, and allowed to remain in the 
balance room until their temperature was the same as 
that of the room. Atmospheric dust was excluded from 
the platinum dishes during the process of deposition by 
means of two glass plates which formed a complete cover ; 
the moisture which collefted on this cover was washed 
back into the dish from time to time. The dishes were 
handled with nickelled tongs tipped with rubber. 

4. The balance used was made expressly for this work 
by Henry Troemner, of Philadelphia. The beam and 
pans were made of aluminum, the beam being about 
20 cm. long. The framework was plated with gold to 
prevent corrosion. The sensibility for different loads and 
the ratio of the length of the two arms were carefully 
determined. The balance is sensitive to the fortieth of a 
m.grm., and the sensibility is almost independent of the 
load up to 75 grms. The difference in the length of the 
two arms is so slight that no correftion need be applied. 
The balance was kept in a large quiet room of nearly 
constant temperature. 

The larger weights used were made of brass, and the 
fraitions of a grm. made of platinum. The weights were 

♦ Contribution from the John Harrison Laboratory of Chemistry 
No. 13. From the author's thesis presented to the Faculty of the 
University of Pennsylvania for the degree of Ph.D. — From the 
Journal 0/ the American Chemical Society, xviii., p. 990. 



all previously compared against each other, and stan- 
dardised with reference to the largest weight. The 
small corre(5lions found in comparing them were tabulated 
and applied to all results. The weighings were made by 
the method of oscillations. The temperature and baro- 
metric pressure were noted at the time of each weighing, 
and all weighings were reduced to a vacuum standard. 
As the density of the atmosphere at the time of weighing 
the empty platinum dish was different from that at the 
time of weighing the dish and deposit together, the fol- 
lowing formula was applied to obtain the weight of the 
deposit in vacuo : — 



Weight of (dish + deposit) — 



weight of dish 



('-!-})' 



'+S-7 

I + - - - = weight of deposit in vacuo. 

Where A = density of air at the time of weighing the 

empty dish. 
A' e= density of air at the time of weighing the 

dish + deposit. 
A = density of platinum dish. 
A' = density of metallic deposit. 
/= density of weights. 

As the weights were all standardised with reference to 
the loo-grm. brass weight, it is evident they must all be 
calculated as having the same density, equal to that of 
brass. 

5. The atomic masses of the different elements in- 
volved in the calculation of results were taken from 
Clarke's latest report (J. Am. Chem. Soc, xviii., 197). 

Part I. 
Determination of the Atomic Mass of Silver. 
The mean of all the earlier determinations, as calcu- 
lated by Clarke, gives 107*923 for the atomic mass of 
silver, — a result almost identical with the mean (i07'93; 
O = 16) of the determinations of Stas. 

Preparation of Pure Metallic Silver. 
The silver used in this work was purified by the Stas 
method. Two hundred grms. of silver, about 99 per cent, 
pure, were dissolved in dilute hot nitric acid. The solution 
was evaporated to dryness, the nitrate heated to fusion 
and maintained in a fused condition until the oxides of 
nitrogen were no longer evolved. The residue, after 
cooling, was dissolved in as little cold water as possible, 
and after standing forty-eight hours the solution was 
filtered through a double filter to remove any suspended 
matter. The clear solution was then diluted with thirty 
times its volume of distilled water, and to it was added 
an excess of pure hydrochloric acid. The silver chloride 
which separated was allowed to subside, and was then 
thoroughly washed by decantation, at first with water 
containing a little hydrochloric acid, and finally with pure 
water. The precipitate was then colledled on a cheese- 
cloth filter, pressed strongly, and allowed to dry. When 
perfedly dry, the silver chloride was powdered finely and 
digested for three days with aqua regia ; it was then 
thoroughly washed by decantation with distilled water. 
After obtaining the pure chloride of silver, it was neces- 
sary to purify the caustic potash and milk-sugar used in 
reducing the chloride to the metallic state. The caustic 
potash was heated to the boiling-point, and to it was added 
a concentrated solution of potassium sulphide to precipi- 
tate any heavy metals which might be present. The 



CRIUICAL NBW8, ) 

Jan. 15, 1897. f 



Manufacture of Calcium Carbide. 



Bolution was filtered, and the filtrate digested for some 
time with freshly precipitated silver oxide, and again fil- 
tered to remove the excess of potassium sulphide. The 
milk-sugar was purified in a similar manner. The silver 
chloride was then placed in large porcelain dishes and 
covered with a solution of caustic potash and milk-sugar. 
The dishes were placed on a water-bath, and heated to a 
temperature of 70° to 80° until the redudlion to finely 
divided metallic silver was complete. The alkaline solu- 
tion was then poured off, and the grey metallic silver was 
washed with distilled water until the alkaline rea(5tion dis- 
appeared. The metal was then digested with pure dilute 
sulphuric acid, and finally washed with dilute ammonia 
water. The silver thus obtained was mixed, when dry, 
with 5 per cent of its weight of fused borax containing 
10 per cent of pure sodium nitrate. The mixture was 
fused in a clay crucible and the silver poured into a mould. 
The metal obtained in this way was almost snow-white in 
appearance, and dissolved completely in nitric acid to a 
colourless solution. 

Preparation of Pure Nitric Acid. 

To obtain pure nitric acid, one-half litre of the com- 
mercial C. P. acid was mixed with an equal volume of 
concentrated C. P. sulphuric acid and distilled from a 
retort provided with a knee-tube and condenser. The 
first portion of the distillate was rejetSted. The process 
was stopped when half of the nitric acid present had been 
distilled over. The distillate was mixed with an equal 
volume of pure sulphuric acid and re-distilled. The second 
distillate was colleded in a flask, the mouth of which was 
closed with glass wool. When the process was complete 
the flask was closed with a doubly perforated cork, and 
placed in a water-bath at a temperature of 40°. A current 
of pure dry air was then condudled through the acid to 
remove any oxides of nitrogen. The acid was kept in a 
dark place. 

Experiments on Silver Oxide. 

If pure, dry silver oxide could be prepared, the atomic 
mass of silver could be compared dire(5tly with that of 
oxygen, A large number of experiments were made on 
this compound with the hope of determining the ratio of 
the atomic mases of these two elements. 

Preparation of Silver Oxide. 

A portion of the pure metallic silver was dissolved in 
pure dilute nitric acid, and the solution evaporated to 
crystallisation. The crystals of silver nitrate were dis- 
solved in pure water, and to the solution was added a 
Bolution of pure sodium hydroxide, prepared by throwing 
pieces of metallic sodium on distilled water in a platinum 
dish. The 25 grms. of silver oxide prepared in this way 
were washed by decantation with 20 litres of water. The 
material was then dried at the ordinary temperature, after 
which it was finely powdered and dried for twenty- four 
hours in an air-bath at 100°. The oxide was kept in a 
weighing tube in a dark place. 

Several analyses were made by dissolving a weighed 
portion of the material in pure potassium cyanide, eledro- 
lysing the solution, and weighing the resulting metallic 
silver. The observations invariably gave less than 95 for 
the atomic mass of silver. The oxide was re-dried at a 
temperature of 125°, and analysed as before, but the quan- 
tity of silver obtained was far below that calculated for 
the compound AgjO. Observations were also made on 
material dried at 140° and 150°. The results showed that 
it was impossible to prepare the silver oxide in a pure, 
dry condition. 

After making these observations my attention was 
called to an article by Carey Lea (Am. f. Sci,, xliv,,24o), 
in which were given the results of a series of analyses of 
silver oxide dried at different temperatures varying from 
100' to 170°, These observations prove conclusively that 
oxygen is given off at a much lower temperature than 
that required to remove the last traces of moisture. 
From these observations and the results obtained by my- 



29 



self, it was evident that any further attempt to determine 
the atomic mass of silver from the oxide would be useless. 
Although no careful study was made as to the nature of 
this compound, it might be added that, from my own ob- 
servations, it seems very probable that the oxide contains 
some hydrogen in the form of hydroxyl. 

(To be continued). 



THE MANUFACTURE OF CALCIUM CARBIDE.* 
By J. T. MOREHEAD and G. de CHALMOT, 

(Continued from p. 18). 

Taking into account the weight of the produA, the time 
in which it has been produced, and the number of horse- 
power used, we calculate for each run the amount of 
pounds produced per horse-power in twenty-four hours. 
By multiplying these figures by the number of cubic feet 
of gas produced per pound we obtained the number of 
cubic feet of gas produced per horse-power in twenty-four 
hours. In the accompanying table we give the results of ex* 
periments, wherein everything has been determined, 
wherein both unslacked and slacked lime have been used, 
and voltage, amperage, and duration of runs were varied. 
Since these results were obtained we have had many 
visitors from all parts of the country, and for each party 
we have made a test run. The results of these runs 
have all confirmed our previous results, with one excep- 
tion, which was due to the presence of 5§ per cent 
magnesia in the lime. 

It is obvious that the results obtained from unslacked 
lime are far better than those with air-slacked lime. This 
is undoubtedly due to a loss of power used in decomposing 
the hydrated lime. The unslacked lime used by us con- 
tained, after being ground, from 5 to 9 per cent of water. 
In pradice it is necessary to use the mixture that comes 
from the furnace again. This mixture always contains 
some carbonate of lime ; but if it be mixed when still hot 
with the necessary amount of carbon, and put again into 
the furnace, the lime has no opportunity to slack. The 
unslacked lime has the further advantage that it weighs 
less and is much less bulky, and that the mixtures made 
from it cool much faster than those made from slacked 
lime. The only disadvantages of unslacked lime are, 
that it must be ground, and that mixtures made from it 
require more stoking if put into the furnace. The mix- 
tures of unslacked lime can stand up against the sides of 
the furnace under a very steep incline, and they can leave 
a hole all around the pencils. The mixture to be used 
should, on an average, contain 100 parts of lime and 64 
to 65 parts of carbon, in order to obtain a carbide of about 
5 cubic feet of gas per pound. If the voltage is increased 
to 100 it is better to take a little more carbon (100 lime 
and 66 to 67 carbon). If the voltage is 65 or less, 63 to 64 
parts of carbon are sufficient. If the amount of carbon 
is increased the carbide becomes purer, but there is often 
more coating. 

The largest amount of gas per horse-power is obtained 
if the carbide yields about 5 cubic feet of gas per pound. 
The yield of carbide in pounds varies inversely with the 
quality. In the following table we give the results of a 
series of experiments made with slacked lime and with a 
current of 65 volts and from 1700 to 2000 amperes. 
Several of these experiments have not been taken up in 
Table JI., becaue the amount of slag on all the pieces of 
carbide has not been determined. 

Carbide has been made successfully in Spray by the 
use of both the diredl and the alternating current. We 
cannot express an opinion as to what current can be used 



* Read Sept. 3rd before the Springfield meeting of the A.A.A.S. by 
one of us (M ). We have made since then several additions, so as to 
make the article complete up to the present time. Fiom the Journal 
of the American Chemical Society, April, 1896. 



30 



Manufacture of Calcium Carbide^ 



i CBBklCAL NbWS, 

I Jan. 15, 1897. 



Date. 

June 27 
July 2 

.. I 

June 24 

„ 28 

July 18 

M 19 

„ 5 

» 9 

Aug. 10 

.. 13 
July 31 



Time of 
experiment. 
Hours. 
2-50 
300 
2*25 
3-20 
2*50 
3-00 

3*00 

375 
4-50 
6-00 
6-00 
7*oo 



Jnne 25 
>• 29 
II ig 
„ 22 
Aug. 14 
July 12 
II 26 
II 12 
» 6 
II 23 
II 22 
II 22 
II 25 
II 20 
it 23 
>i 24 



5 '00 

4*00 
5*50 
4'oo 
4-50 

375 
8-00 
5-50 
5*00 
3 '00 

2-00 
2*00 

9*00 
4*00 
5*00 
8-00 



Volts. 

100 
100 
100 
100 
100 

65 
65 
65 
65 
65 
65 

75 



100 
100 



75 
85 
75 
85 
80 

65 
65 
65 
65 
65 
65 
65 



Amperes. 

1700 
1666 
1700 
1600 
1700 
2000 

igoo 
2000 
2000 
1800 
1800 
1800 



Table II. 

Lobs of 

voltage in 

the pencils 

Per cent. 

7-0 

8-0 

lO'O 

7'o 

lO'O 

5*0 
5'o 
5'0 
5*o 
8-0 
8-0 
8-5 



— Unslacked Lime. 



Horse- 
power, 

214 
205 
205 
214 
205 
165 
158 
165 
165 
144 
144 
166 



Production 

in 24 hours, 

including slag. 

Pounds. 

987 
10-34 
io'66 
1 1 "50 
1 1 70 

9-63 
io'40 

8-38 

g'5o 

g"34 
1083 

11-44 
Average . , 



Net pro- 

dudtion. 

Pounds. 

942 

g76 

lO'IO 

1073 

II-IO 

915 

9'62 
8-I5 
9-05 
g'oo 

10-44 

io'53 
g75 



Table III. — Air-slacked Lime. 



1700 
1700 
1700 
1600 
1700 
1800 
1800 

1775 
1020 
1800 
1800 
1800 
1800 
1800 
1800 
1800 



7-0 

lO'O 

7-0 

7'o 
7-0 

3 5 
5'o 
S-o 
3-0 
5'o 
5'o 
5'0 
5-0 
5*o 
50 
50 



214 
205 
214 
igg 

I5g 
igS 
172 

185 
200 
150 
150 
150 
150 
150 
150 
150 



Per horse-power. 
8-34 
8-78 

925 
g-8o 
7-88 

8-40 

878 
6-83 
7*13 

7*20 

772 

8 -60 

g-02 

9-30 

Average . . 



7-96 
8-34 

965 
7-13 
6-33 
7-23 
7-32 
8-i6 
6-40 
6-40 
6-40 
7-27 
8-00 
8-00 
803 
7'5i 



Cubic feet Cubic feet 

of gas per of gas per horse- 
hour, power in 24 hrs. 



4-83 
5*25 
4-65 

4 '93 

475 
495 
4-83 
5-40 

4'9g 
5"3g 
4-82 

4-83 
497 



Per pound. 
530 
4-98 
4-89 

474 
550 
5'55 
5 33 
5*32 
5'" 
578 
5"62 
5-64 
5'54 
5-OI 
5-07 

4'97 
5-27 



45 -50 
5i"24 
47-06 
52-90 
52-72 
45*29 
46-46 
44-01 
4516 
48-51 
50-32 
50-86 
48-33 



42-19 
4i"53 

4575 
3g'22 

35*1:3 
38-54 
38-g4 
41-70 
56 -gg 

3597 
36-09 
40-28 
4008 
40-56 

39gi 
39-52 



Date. 
July 23 
June 14 
July 22 

„ 22 

.. 25 
Aug. 14 
May 21 

„ 22 
July 26 
June 4 
July 20 
June 5 
May 28 

., 23 
July 23 
June 8 

I. 24 
July II 
Aug. 12 
May 31 
Aug. 8 



Table IV. 

Produftion per horse- 
power including slag. 
Pounds. 

685 

7-10 

7-13 
7-20 
7-72 
7-88 
8-IO 
8-30 
8-40 
8-46 
8-6o 
8-76 
8-80 
8-82 
9-02 
9-06 
930 
9-30 

9-44 

9-87 

10-52 



Cubic feet 

of gas 
per pound. 

5-78 
5-80 
5*62 
5-64 
5-54 
5-50 
5-20 
5-10 
5 "33 
5-52 
5-01 

4'94 
5-20 
5*io 

5-07 
5-10 

4 '97 
4-33 
4-51 
4-30 
4-23 



to the best advantage, for we are not able to compare 
results. All of the results communicated in this paper 
have been obtained by the use of the alternating current. 
That eledrolysis plays a part in the carbide manufaduring 
process of Mr. Wilson is therefore cut of the question, 
and we do not need to use a furnace of the Moissan con- 
strudion to prove this. It is not desirable to increase the 
amperage over 2000 if only six carbons of 4 inches square 
are used. The higher the amperage the greater the loss 
of voltage in the pencils, and therewith that of power. 
The carbons will also last longer if the amperage is low, 
because they do not become so hot. Lastly, we did not 



obtain as great a yield per horse-power if the amperage 
was high and the voltage correspondingly low. We ob- 
tained the best yield of gas per horse-power by using a 
current of 100 volts, which can be seen by comparing the 
average of the results given in Table II. 



Volts. 
Unslacked f 100 
lime ..I65— 75 



Slacked 
lime • 



100 

75-85 

65 



Table V. 

Horse- 
power. 

205—214 
144—165 

200—214 

i5g— 100 

150 



No. of 
experi- 
ment. 

5 
7 

3 
5 
7 



Average cubic 

feet of gas per 

horse' powef 

in 24 hours. 

49-88 

47-23 

43-15 
3871 
38-55 



It must be taken into account that we measured the 
primary current, and that the losses of amperage in the 
transformers probably have been higher when we did not 
use the highest voltage, f. <., 100. We do not know in 
how far it would be advisable to increase the voltage over 
100, since our dynamos cannot give us a current of more 
than 100 volts. We believe, however, that the heat 
yielded by an arc of 100 volts, and from 1700 to 2000 
amperes, is about the largest amount to be profitably used 
for the produdion of carbide in one furnace with six 
pencils, as it is used in Spray. We base our assumption 
on the following fads : — The quality of the carbide be- 
comes better if the voltage decreases. We experienced 
some trouble in obtaining large carbide crystals with an 
arc of 100 volts and 1700 amperes, and in order to obtain 
a carbide that yields more than 5 cubic feet of gas per 
pound the mixture should contain an excess of carbon. 
If a current of 100 volts and 1700 amperes is used, the 
furnace requires more attendance and stoking than if a 
lower power, and especially a lower voltage, is used. 
The higher the voltage the faster the pencils must be 



Chruical Nbws, I 
Jan. 15, 1897. I 



Derivatives of Columbium and Tantalum, 



31 



raised, for if the voltage is low (50 or 65) the carbide 
spreads oat much more than if the voltage is high (100 
volts). In the latter case the carbide builds up as a long 
thin piece, and it is oftener necessary to empty the fur- 
nace. As to the time that one furnace should be used 
continuously, we wish to say that we did not perceive a 
difference in the quantity and quality of the produdt 
whether we ran three hours or from three to nine hours. 
We must, however, remark that in the case where we used 
100 volts and 1700 amperes with mixtures of unslacked 
lime we could not continue running for much more than 
three hours, because the construdlion of the furnace did 
not admit of raising the pencils quite 3 feet. With 
slacked lime we made also with this high power very 
satisfadtory runs of five and five and a half hours. During 
the first hour the produdtion is somewhat lower. It 
seems that more heat is lost probably for heating up the 
furnace. 

The mixture used in all of the following experiments 
contained lime 50*08 per cent, and coke (of 92*17 percent 
of carbon), 39'22 per cent. The current was of 65 volts 
and 1800 amperes, the loss of voltage in the pencils 5 per 
cent, and the net horse-power 150. 







Table VI. 




Time of 


Produdtion 


Cubic feet 


Cubic feet 


experiment. 


per hour 


of gas 


of gas 


Hours. 


in pounds. 


per pound. 


per hour. 


I 


37 


563 


208*31 


3 


40 


5'62 


224-80 


2 


40 


5*64 


225*60 


3 


40 


578 


237*20 




(To be continued). 





DERIVATIVES OF COLUMBIUM AND 

TANTALUM.* 

By MARY ENGLE PENNINGTON. 

(Continued from p. 20). 

Qualitative Reactions, 
Throughout this investigation the following questions 
constantly arose : How shall the purity of the columbium 
and tantalum compounds be determined. When is 
columbium free from tantalum ? When is it free from 
titanium ? 

In the earlier work upon columbium we find Hermann 
describing a new element which he obtained from the 
mother liquors of the columbium potassium fluoride. 
This element, he states, gave a dark brown solution when 
reduced with zinc and hydrochloric acid, while the pure 
columbium compound gave a blue colour. Both these 
solutions, on standing in the air, reverted to the white 
hydrate. Marignac replied that the brown colour was 
not due to ilmenium, but to titanium, a view which is now 
generally accepted. 

He also declares that a brown colour is produced when 
the potassium columbium oxyfluoride is treated with zinc 
and hydrochloric acid, the acid being in considerable 
excess. Then, by titrating with permanganate, he found 
that an intermediate oxide had been formed, to which he 
gave the formula CbsOs. 

Crystals of the columbium salt, prepared as described 
above, continued to give this brown solution even after 
they had been subjedled to five or six re-crystallisations. 
Following the plan of Kriiss and Nilson {Ber. d. Chem. 
Ges., XX., 1676), the atomic value of the oxide contained 
in such crystals was determined by decomposing with 
sulphuric acid, weighing the pentoxide and the potassium 
sulphate, then, by the ratio 2K2SO4 ;Cb205, determining 



♦ From the author's thesis presented to the University of Penn- 
sylvania for the degree of Ph.D., 1895, From the Journ. Amer. 
Chem, Soc, xviii., January, i8g6. 



the value for Cbv. This was found to be 85*7. Iron and 
manganese has been eliminated ; titanium therefore was 
the probable cause of this low atomic value. The salt 
used was perfeAly white, yielding a pure white oxide. 
This oxide was tested for titanium by the most delicate 
reactions known for the metal, but its presence could not 
be proved by any of them. 

I. Colour and Reduction Reactions, — It has been found 
that the qualitative tests given in the various text-books 
for these three elements do not always hold good when 
the solution used is a double fluoride. As it is in this 
form that the separations are usually made, it has been 
thought advisable to note the aiftion of some of the 
common reagents on these salts. 

Gallotannic acid, which is considered the most charac- 
teristic test for columbium salts, behaves differently with 
different double fluorides. An acid solution of the lami- 
nated salt gives almost instantly a deep brick-red pre- 
cipitate. The salt, crystallising in long needles, gives a 
lighter red precipitate which does not separate so rapidly. 
The large, thin, transparent plates previously mentioned 
give only a slight precipitate, and this is yellow in colour. 
These readions are most delicate if the salt be dissolved 
in water, a drop of hydrochloric acid added, then a little 
gallotanic acid dissolved in alcohol. After standing 
several hours all the precipitates assume the same colour 
— a dark brick-red. 

Tantalum double fluoride gives a sulphur-yellow colour 
with gallotannic acid. This, however, on standing, be* 
comes brick-red, as the columbium does. 

Titanium compounds are said to give a brownish colour 
with gallotannic acid, which changes quickly to an orange- 
red. The potassium titanium fluoride gave a straw-yellow 
colour with this reagent ; in time a flaky precipitate forms, 
but the colour does not materially alter. 

The following colour readtion serves for the detedtion 
of very small quantities of columbium, and is applicable 
to any soluble columbium compound. An excess of 
potassium thiocyanate is added to a small quantity of the 
dissolved substance ; then some pieces of zinc followed 
by strong hydrochloric acid. At once the solution be- 
comes a bright golden brown, which, if much columbium 
be present, may be almost red. A brisk and continued 
evolution of the gas does not alter this tint, which is 
also stable for more than twenty-four hours in the acid 
solution. Neither titanium nor tantalum give any re- 
adtion with potassium thiocyanate under the above con- 
ditions. 

Hyposulphurous acid, HaSOa, gives noteworthy colour 
readtions with these salts. The tests were condudted in 
the following manner : — A few cubic centimetres of a 
concentrated solution of sulphur dioxide were placed in 
a test-tube provided with a cork, and granulated zinc was 
added. The liquid changed to a greenish colour, and 
hydrogen was liberated. As soon as the evolution of 
the gas had ceased the solution containing the hypo- 
sulphurous acid was poured into the salt solution to be 
tested. 

A solution of titanium double fluoride gave an orange- 
yellow colour at once. The oxide, when treated in like 
manner, became yellow. 

Columbium double fluoride gave no colour, but a white 
hydrate was soon precipitated. Columbic oxide gave a 
slight yellow tinge. 

Tantalum double fluoride gave no colour, but after 
standing a white precipitate separated. Tantalic oxide 
remained colourless when treated with hyposulphurous 
acid. 

The white precipitates from the tantalum and colum- 
bium salts were probably hydrates due to the oxidation 
of the acid and its consequent adtion upon these salts. 

Zinc and hydrochloric acid gave no readlion with the 
double fluoride of tantalum. With titanium a clear deli- 
cate green was obtained. The columbium salts always 
gave a colour with these reagents. The solution is at 
first dark blue, then a greenish brown, and finally a dark 



32 



Derivatives of Columbium and Tantalum, 



(Crbmioal News, 
I Ian. 15, 1897. 



Lead acetate. 
Mercuric chloride. 

Mercurous nitrate. 
Potassium chromate. 



Potassium bichromate. 
Potassium cyanide. 
Potassium ferrocyanide. 

Potassium thiocyanate. 



Potassium iodide. 

Disodium hydrogen phos- 
phate. 
Silver nitrate. 

Sodium bisulphite. 
Sodium pyrophosphate. 
Hypophosphorous acid. 
Sodium metaphosphate. 
Potassium bromide. 



zKF.CbOFa.HjO, 
White precipitate. 
Slight precipitate in 24 

hours. 
Yellow precipitate. 
White precipitate, soluble 

in H2O. Partly soluble 

K2Cr04 solution. 

White precipitate on boiling. 
Green-blue precipitate on 

boiling. 
White precipitate. 



White, granular precipitate. 
Iodine is liberated. 



White precipitate. 



2KF.TaF4. 
White precipitate. 

Yellowish-green precipitate. 



Precipitate after standing. 

White precipitate. 

Yellow precipitate on boil- 
ing. 

White precipitate soluble in 
the cold. Comes down 
by boiling. 

White granular precipitate. 



White precipitate. 



White precipitate 

standing. 
White precipitate 

standing. 
White precipitate. 
Slight cloudiness. 

Slight cloudiness. 



after 
after 



sKF.TiFt. 
White precipitate. 



Yellowish-green precipitate. 
Precipitate soluble in water. 



White precipitate. 
Precipitate on boiling. 



No precipitate, but iodide is 

liberated. 
White precipitate. 



White precipitate. 

Precipitate. 

Precipitate. 



•brown. Frequently a brown precipitate separates, which, 
on standing, becomes white. 

The hydrochloric acid solution of columbic oxide, and 

-also the potassium columbium fluoride, were tested with 
hydrogen peroxide, this being accepted as one of the most 
delicate reagents for titanium. No yellow colour in either 
case was obtained. 

2. Reactions with Wet Reagents, — A number of the 
ordinary reagents have been tried with these salts, the 
results being given in the table above. The readions 
for the greater number are very different when the metal 
tested is as double fluoride. The ferrocyanides, in par- 
ticular, have quite abandoned their ordinary colours with 
these compounds. 

Disodium hydrogen phosphate, when added to titanium 
double fluoride, precipitates the titanium completely. 
The flltrate, tested with ammonium hydroxide, gave no 
precipitate. Columbium double fluoride, on the con- 
trary, is not affe&ed by this reagent. After boiling a long 
time in a platinum dish a few white flocks were observed 
in the solution, but in such small quantity that they were 
disregarded. Whether this behaviour may or may not be 
made the basis of a separation of these two elements is 
not yet determined, because of the difficulty in getting 
rid of the phosphoric acid. Fusion with sodium car- 
bonate, extradtion with water, and subsequent precipita- 
tion by sulphuric acid gives a mixture of sodium salt 
and columbic oxide. Some columbium remains in solu- 
tion. Fusion with potassium acid sulphate is more satis- 
faftory, yet is not complete. 

Deportment of Tantalum, Columbium, and Titanium 
Double Fluorides toward the Electric Current. 

1. A solution of potassium columbium double fluoride, 
2KF.CbOF3.H2O, in water, was treated with a small 
amount of sodium acetate. The precipitate formed was 
dissolved in acetic acid, and through this solution a 
current of one ampere, obtained from a thermopile, was 
condudled for five hours. A white precipitate, seemingly 
a hydrate, was formed. On breaking the current, this 
rapidly went into solution. 

2. (a) A solution of the salt in water was subjei5led to 
the same current for eight hours. Almost immediately 
the bottom of the platinum dish was covered with a 
blue deposit. This gradually spread over the whole 
surface exposed to the adtion of the current, and be- 
came in a short time iridescent. As the deposit in- 
creased, the deep blue tint changed to more of a grey, 



and remained so until the current was broken. It was 
washed quickly with water, then with alcohol, and it was 
dried on the hand. 

o'i3i5 grm. of the salt was taken ; the deposit weighed 
o*0282 grm. This metallic-looking substance did not 
alter in the air, but, on subjecting it to a red heat, a 
white, shining, apparently crystalline compound resulted. 
It was readily soluble in hydrofluoric acid. 

{b) A second experiment, with o'2i95 grm. of the sub- 
stance, gave, under the same conditions, a deposit weigh- 
ing 0*0388 grm. This, when ignited in the air, burned 
to a white oxide weighing o-o3i2 grm. The blue com- 
pound is, in all probability, a lower hydrated oxide of 
columbium. 

3. The eledrolysis of an aqueous solution of a sodium 
columbate gave a white flocculent hydrate, not adherent 
to the dish. The precipitation was not complete. A 
current of one ampere was employed for a period of 
seven hours. 

4. With a much stronger current (two amperes), a 
solution of the double salt 2KF.CbOF3.H2O, gave first 
a white hydrate, then, beneath the outer edge of the 
anode appeared a dark brown ring which gradually grew 
in towards the centre of the dish, never reaching it, 
however, but stopping when about half an inch in 
width. 

This brown substance was slightly adherent to the 
dish, but just as soon as the current was broken, and 
the liquid poured off, it reverted to the white hydrate. 
This change was so rapid that it was impossible to sepa- 
rate the brown from the white substance. 

Thinking that this brown compound might be a con- 
taminating element, about i grm. of the double salt was 
dissolved in water and eledlrolysed until the brown ring 
had appeared. Then the liquid was poured into another 
dish as quickly as possible, and the current run through 
again. The brown ring appeared as before, and was 
treated in the same manner. After changing the dish 
four times only a trace of brown could be seen. When 
the remaining solution was evaporated it was found that 
almost the entire quantity of the columbium had been 
precipitated. The brown substance here formed resem- 
bles in its behaviour that produced in a like solution by 
zinc and hydrochloric acid. 

The resistance of this solution is very high. 

5. Potassium tantalum fluoride, in aqueous solution, 
was subjected to the adlion of a current of two amperes 
for six hours. A small quantity of hydrate was found in 



CatHICALNBWS, I 

Jan. 15, 1897. f 



Derivatives of Columbium and Tantalum, 



33 



the liquid, and on the dish a very slight iridescent de< 
posit mixed with some white hydrate. 

6. Potassium titanium fluoride was treated in the same 
manner as the previous salt. A small quantity of hydrate 
was found here, some of which adhered to the dish. The 
iridescent deposit, however, was wanting. 

Action of Hydrofluoric Acid upon the Oxides of Tantalum, 
Columbium, Titanium, and Silicon. 

The well-known volatility of the oxides of tantalum 
and columbium, when healed with hydrofluoric acid, led 
to the hope that in this behaviour might lie a separation 
from titanium, and also from silica. 

Rose states that a very appreciable loss occurs when 
the first two oxides are treated as suggested, but he 
makes no attempt to separate them from the latter two. 
To this end i grm. of the mixed oxides of tantalum and 
columbium was evaporated to dryness with hydrofluoric 
acid, the residue being heated over the free flame for a 
few minutes. By this treatment dense white vapours 
were driven off. Upon weighing the residual oxides they 
were found to equal 0*5464 grm. A second evaporation 
gave further loss, but as both columbium and tantalum 
continued to remain, the method is without value. 

The separation of silica from these oxides can be ac- 
complished by the heat of an iron plate after evaporating 
to dryness on a water-bath. The final heating must be 
carefully done, and the acid should not be in too great 
excess. 

I have never found it impossible to dissolve either the 
mixed or the pure oxide in hydrofluoric acid, even though 
strongly ignited. It is true, concentrated acid is neces- 
sary, and a little time is often required, but a perfedt 
solution does take place. 

Tantalic oxide, containing columbic oxide, is far more 
soluble in hydrofluoric acid than the pure oxide. The 
same behaviour has been observed with pure columbic 
oxide, though it is not so pronounced as with tantalic 
oxide. Titanium dioxide, ignited, is very difficultly 
soluble in this reagent, though columbic oxide, containing 
titanic oxide, went quickly into solution. 

Double Fluorides of Tantalum. Columbium, and Tita- 
nium, with Rubidium and Ccesium. 

The potassium double fluorides of tantalum and colum- 
bium have been found of great service in separating 
these two metals. Marignac first showed that a separa- 
tion could be effected through these salts, and he also 
demonstrated that the sodium and ammonium salts were 
inapplicable. 

Of the potassium double fluorides of tantalum and 
columbium we possess considerable information. A 
number have been isolated and studied. The sodium 
salts crystallise so poorly that their history is not so 
well known. It seemed probable that rubidium and 
caesium would form double fluorides of definite crys- 
talline charader with these three metals. At least, a 
study of their behaviour might be found instrudive. Be- 
fore taking up their preparation, however, the simple 
fluorides of rubidium and caesium may be discussed. 

Rubidium Fluoride (RbF). — An examination of the 
literature on rubidium showed that its fluoride had not 
been prepared. In order to procure this rubidium iodide 
was dissolved in water, and moist silver oxide added to 
precipitate the iodine. The solution of rubidium hydrate 
resulting was filtered off and evaporated in porcelain 
dishes. A very appreciable quantity of silver oxide was 
held in solution by the rubidium hydroxide, so that it was 
necessary to evaporate it almost to dryness, then to take 
it up in the smallest possible quantity of water, and filter. 
This treatment may have to be repeated two or three 
times before the solution is perfeftly colourless. When 
quite free from silver, the concentrated solution was made 
slightly acid with hydrofluoric acid, and evaporated. If 
hydrofluoric acid be present it is almost impossible to 
obtain crystals, a thick syrup being formed which defies 



all attempts in this diredtion. The solution is therefore 
evaporated with water several times until the excess of 
acid is expelled. The rubidium fluoride then crystallises 
in long, transparent plates. These were drained, and 
dried between filter paper. The salt was anhydrous. 
Conversion into sulphate by evaporating with sulphuric 
acid gave, from 0*5 grm. of the salt, 0*5236 grm. ru* 
bidium sulphate. This corresponds, therefore, to the 
formula RbF. 

Casium Fluoride. — Caesium chloride was dissolved in 
water, and the chlorine precipitated by moist silver 
oxide. The solubility of the oxide of silver in caesium 
hydrate is even greater than in rubidium hydrate, there* 
fore some difficulty was experienced in obtaining a hy- 
drate free from silver. It was finally accomplished by 
evaporating to dryness repeatedly, taking up the caesium 
hydrate in a very small quantity of water, and filtering 
it. The pure hydrate was then neutralised with hydro- 
fluoric acid and evaporated. A thick syrup was obtained 
which refused to crystallise. Upon heating in an air 
bath to 130° C, a crystalline mass formed, but it was 
always in such a sticky condition, and absorbed mois- 
ture so rapidly, that it could not be analysed satis- 
fa(5torily. This mass was dissolved in water and added 
to the solutions of the metals in hydrofluoric acid. 

Double Fluoride of Columbium and Rubidium. — One- 
half grm. of columbic oxide was dissolved in hydro- 
fluoric acid and the calculated quantity of rubidium 
fluoride added. The solution was evaporated on a water- 
bath to expel the excess of acid. The residue was 
taken up in hot water and allowed to crystallise spon- 
taneously. White microscopic plates separated. These 
were filtered off, dried between filter paper, and analysed. 
Two-tenths grm. of the dry salt gave — 





Found. 


Calculated for 
2RbF.CbF4. 


Difference. 


CbaOs .. 
RbF .. 


0*0670 
0-1048 


0*0673 
0*1049 


— 0*0003 
-O'OOOI 



The formula of the salt is therefore zRbF.CbFs, corre- 
sponding to the tantalum salt usually obtained with 
potassium fluoride. 

The filtrate from this first crop of crystals was slightly 
concentrated, when small, shining, or even iridescent 
crystals, apparently plates, separated. Upon standing a 
short time, these changed over into crystals like those 
first mentioned. This salt is very soluble in water con- 
taining hydrofluoric acid, and also in pure water. It is 
insoluble in alcohol. 

Double Fluoride of Rubidium and Tantalum. —Ra- 
bidium fluoride in slight excess was added to tantalic 
oxide dissolved in hydrofluoric acid. Small white needles 
crystallised out. An excess of acid must be present, 
otherwise heat decomposes the double salt, giving a fine, 
white, insoluble compound, as is the case with the potas- 
sium salt. 

Analyis of ^^ grm, gave 

Cakulated for 
Found. 2 RbF.TaFi. Difference. 

Ta205 .. 0*0915 0*0913 -+-0*0002 

RbF .. o*o86i 0*0859 -f-o*ooo2 

Double Fluoride of Titanium and Rubidium. — The pre- 
paration of this salt was conducted as described with pre- 
ceding salts. The crystals here were also microscopic 
needles. Some difficulty was at first experienced in com- 
pletely drying the salt, but this was overcome by several 
re-crystallisations from pure water, when an anhydrous 
produ(a was obtained. One-tenth grm. of the salt gave, 
on analysis — 

Calculated for 
Found. sRbF.TiF*. Difference, 

Grm. Grm. 

TiOj .. 0*0238 0*0240 —0*0002 

RbF .. 0*0622 o*o526 —0*0004 



34 



Chemical Notices from Foreign Sources 



f Chemical News, 
\ Jan. 15, 1807. 



Double Fluorides of Tantalum and Ctzsium.* — This 
double salt was formed by the addition of a solution of 
the caesium hydrate in hydrofluoric acid to a solution of 
tantalic oxide in hydrofluoric acid. Very beautiful white 
needles separated, which were not easily soluble in water, 
and were not decomposed by re-crystallisation from pure 
water. The aqueous solution may be evaporated on a 
water-bath with perfed safety, this salt being apparently 
much more stable than either the potassium or rubidium 
salt. 

The crystals were dried in the air, then heated to 
125° C. in an air-bath. No loss in weight was observed. 
0'25 grm. gave, on analysis — 

Calculated for 
Found. isCsF.TaFj. Difference 

TaaOs .. 0-02I2 o-oaij -0*0005 

CsF .. .. 0*2232 0-2228 —0*0004 

The formula deduced from the analytical data varies 
widely from that generally followed by tantalum double 
fluorides. Neither is it in accordance with Remsen'slaw 
for the double halides {Am. Chem. y., ii., 291), though it 
will be observed that its fluorine content bears a simple 
ratio to the fluorine in combination with the tantalum. 

Double Fluoride of Columbium and CcEsium,— This 
double salt was formed in the manner described for the 
preparation of the caesium tantalum fluoride. It is very 
soluble in water containing hydrofluoric acid, and in pure 
water, from which it crystallises in needles. These, when 
pure, are anhydrous. Boiling with pure water does not 
decompose the salt. Analysis of ^^ grm. gave the fol- 
lowing result : — 

Calculated for 
Found. 7C8F.CbF4. Difference. 

CbaOs .. o*02i6 0*0213 -1-0*0003 

CsF .. .. 0*1694 0*1698 -0*0004 

This salt, which appears to be 7C8F.CbF5, is even 
more erratic in its constitution than the tantalum caesium 
compound. There is apparently no relation here between 
the fluorine in combination with the columbium and the 
number of molecules of caesium fluoride present. 

Double Fluoride of Titanium] and Ccesium. — This salt 
separates in very small, shining crystals when caesium 
fluoride is added to a rather concentrated solution of 
titanic oxide in hydrofluoric acid. It is more readily 
soluble in water than the tantalum caesium compound, 
and is not decomposed by pure water. The air-dried 
crystals showed no loss in weight after heating for some 
time at 125° C. An analysis of 0*25 grm. gave the fol- 
lowing amounts of titanic oxide and caesium fluoride : — 

Calculated for 
Found. 4CsF.TiF4. Difference. 

TiOa .. 0*0269 0*0271 -f-o*ooo2 

CsF .. .. 0*207 1 0*2076 —0*0005 

The figures point to the formula 4CsF.TiF4. This is 
a departure from the usual titanium double fluorides, and 
agrees with the law laid down by Remsen for these salts. 

When we consider the atomic masses of tantalum, 
columbium, and titanium, the first 182, the second 94, 
and the third 48, and also consider the quantities of 
caesium fluoride which unite with a molecule of each of 
the metallic fluorides, we find that with tantalum the 
quantity (fifteen) is nearly twice that with columbium 
(seven), and the latter almost double that (four) uniting 
with titanium, just as 182 is about twice 94, and 94 
nearly twice 48. 

These new caesium compounds tend to confirm the con- 
clusion drawn by Wells and others {Amer. yourn. Set., 
xlvii.) from their work on the caesium double halides. The 
compounds investigated by these chemists show that the 
caesium double halides are not wholly conformable to 
Remsen's law. 

* This and all the other caesium double fluorides are being subjefted, 
at this writing, to further study in this laboratory.— E. F. Smith. 



The method of analysis pursued for the determination 
of these double salts is, briefly, as follows : — 

The dry substance was decomposed in a platinum 
crucible by a few drops of concentrated sulphuric acid. 
The hydrofluoric acid was driven off, and the excess of 
sulphuric acid was then expelled on a sand-bath. The 
temperature must be just sufficient to drive off the acid. 
The metallic oxide was obtained from the sulphate by 
long boiling with a large quantity of water. It was then 
filtered, washed about twenty times with boiling water, 
ignited, and weighed. The filtrate containing the alka- 
line sulphate was evaporated, the excess of acid neutralised 
with ammonium carbonate, and the solution then evapo- 
rated to dryness on a water-bath. A saturated solution 
of ammonium carbonate was added, and the mixture 
evaporated again to dryness. The ammonium salts were 
expelled by careful heating. Constant weight can gene- 
rally be obtained after two or three evaporations with 
ammonium carbonate. The rubidium sulphate decrepi- 
tates on heating, which necessitated great care while 
expelling ammonium salts, and also rendered the method 
proposed by Kriass (heating in a stream of ammonia gas) 
untrustworthy. The alkalies were then weighed as 
normal sulphate, and the caesium or rubidium content 
calculated. This method, while slow, has been found 
very satisfadlory for these rare alkalies. 
(To be continued). 



OBITUARY. 



THE LATE DR. EMIL DU BOIS REYMOND. 

This most distinguished physiologist concluded his fruit- 
ful and honourable career on December the 26th. The 
deceased, perhaps our highest authority in the wide and 
interesting region of animal eledtricity, was born at Berlin 
on November 7th, 1818. As his name indicates, he was 
of French descent. He studied firstly theology, at the 
University of Berlin, but soon turned his attention to the 
more congenial subjedt of medicine, becoming one of the 
most prominent pupils of Johannes Miiller, and soon 
acquired — as, indeed, he richly merited — a world-wide 
celebrity. In 1851 he was eledled a member of the Royal 
Prussian Academy of Sciences, and in 1867 he was 
appointed Perpetual Secretary, an office which he filled 
up to his death. His eminence was needed as a counter- 
poise to the quackery which was and is still seeking to 
degrade the study of animal elei5tricity. 



CHEMICAL NOTICES FROM FOREIGN 
SOURCES. 



Note.— All degrees of temperature are Centigrade unless otherwise 

expressed. 

Com/lies Rendus Hebdomadaires des Seances, de VAcademie 
des Sciences. Vol. cxxiii., No. 26, December 28, 1896. 

An interesting ceremony took place at the Institute 
Pasteur on the transfer of the remains of the late illus- 
trious iavant to the crypt specially designed for his recep- 
tion. The principal personages present were: — M. 
Rambaud, the Minister of Public Instruction, on behalf of 
the Government; M. Baudin, President of the Municipal 
Council, on behalf of the city of Paris ; Sir Joseph Lister, 
President of the Royal Society of London, Foreign Asso- 
ciate of the Academy of Sciences, on behalf of the Royal 
Society, and of the Royal College of Surgeons of London ; 
I Sir W. Priestley, on behalf of the Universities of Edin- 



SBBMICAL NBVfTSi I 

Jan. 15, 1897. ' 



Chemical Notices from Foreign Sources, 



35 



burgh and St. Andrews; Sir Dyce Duckworth, on behalf 
of the Royal College of Physicians of London ; M. A. 
Cornu, President of the Academy of Sciences ; M. Berge- 
ron, Perpetual Secretary of the Academy of Medicine; 
M. L. Passy, Perpetual Secretary of the Society of Agri- 
culture ; and M. Duclaux, Dire(5ltor of the Institute 
Pasteur, 

New Application of Radioscopy to the Diagnosis 
of Maladies of the Thorax. — Ch. Bouchard. — Details 
of some cases of no chemical interest. 

The Energy expended by a Muscle in Static Con- 
tradlion for the Maintenance of a Charge after 
Respiratory Exchanges. — A. Chauvereau, with the 
collaboration of M. Tissot. — The conclusion from the 
authors' first series of experiments is, that the quantities 
of oxygen absorbed and of carbonic acid exhaled — /. e., of 
the energy expended for the maintenance of a charge — 
increase with the muscular contradion, although the 
charge remains constant. The conclusion from the second 
series of experiments is that the oxygen absorbed and the 
carbonic acid exhaled — i. e., the energy brought into play 
for the maintenance of a charge — increase sensibly in the 
same manner as such a charge. 

New Radioscopic FaiAs concerning Intrathoracic 
Lesions — J. Bergonie. — This paper has no chemical 
bearings. 

A(5tien of Lithium upon Carbon and certain Car- 
bides. — M. Giintz. — This paper will be inserted at some 
length. 

On the Chlorine Carbide, C3CI3. — Paul Lemoult. — A 
thermo-chemical paper. 

A(5\ion of the Carbonic Acid of Waters upon Iron. 
— P. Petit. — The a(5lion of iron upon calcium bicarbonate 
and upon carbonic acid in solution enables us to explain 
the attack of iron pipes and tanks in certain waters. It 
gives also the mechanism of the purification of waters by 
iron, and the purification of syrups by iron-filings in the 
sugar manufacture. 

A(5\ion exerted upon Solutions of Alkaline Haloid 
Salts by the Acids present. — A. Ditte. — On adding 
the acid to the solution of a neutral salt, we determine at 
first a decrease of the solubility, but it does not increase 
without limit with the quantity of acid added. 

Adtion of Phosphorus upon Platinum. — A. Granger. 
— Until recently only platinum biphosphide was known. 
In 1884 two American chemists, Clarke and Joslin, 
obtained a definite compound, PtsPs, which dissolves par- 
tially in aqua regia, leaving an insoluble protophosphide, 
PtP. The dissolved matter contains the biphosphide, 
PtP2. The author, on repeating this experiment, ob- 
tained a subphosphide, PtzP. At white redness the mass 
retained only 4 per cent as phosphorus. 

Adtion on Gaseous Hydrochloric Acid upon the 
Alkaline Sulphites. — Albert Colson. — Experiment shows 
that, contrary to the opinion of some savants of authority, 
sodium sulphate, S04Na2, is attacked in the cold by dry 
HCl. There exist small series of tensions of hydrochloric 
acid gas. 

The Redudtion of Tungsten by Coke in the Eledric 
Furnace. — Ed. Defacqz. — This memoir will be inserted 
in full. 

New Instances of Normal Rotatory Dispersion — 
Ph. A. Guyeand P. A. Melikion. — The substances being 
arranged according to the increasing values of [a]D we 
remark that the specific rotatory dispersions remain of 
the same order of magnitude, but they are not propor- 
tional to the specific rotatory power. 

Transformation of the Sulphonated Campho- 
phenols into Dinitro-orthocresol. — P. Cazeneuve. 

On Hexa-diimediol. — R. Lespieau. 
The Congelation-point of Milk. — J. Winter. — A 
controversial memoir in reply to MM. Bordas and Genin, 



A Contribution to the Study of the Borneols and 
their Ethers.— J. Minguin. — These last papers are not 
adapted for abstradlion. 

Optical Analysis of Urine and Exadt Determina' 
tions of the Proteids, Glucosides, and Non-ferment- 
ible Saccharoid Matters F.Landolph.— (See p. 25). 



Hevue Universelle des Mines et de la Metallurgie, 
Series 3, Vol. xxxvi., No. i. 
Determination of Sulphur in tha Produdls of 
Siderurgy. — The methods for the determination of sul- 
phur in siderurgical produAs are classified under the 
following heads : — Procedures for the diredt oxidation of 
sulphur by the moist or the dry method, followed by pre- 
cipitation as barium sulphate either with or without a 
previous elimination of iron ; procedure for diredt chlori- 
nation by the dry method, and precipitation as barium 
sulphate ; procedures by hydrogenisation of the sulphur 
in the dry way ; procedures of evolution, HjS being 
liberated by the adlion of dilute acids and either oxidised 
to form SO3 or absorbed by saline solutions ; mixed pro- 
cedures. This lengthy memoir, which extends to 90 pages, 
requires the accompanying figures. 



MISCELLANEOUS. 



To Soda and Ultramarine Manufadturers. — Rud 
C, Gittermann writes as follows from Odessa, South 
Russia, under date January 8th, 1897 • — " I' '"^y interest 
your readers that we are in great want here of manufac- 
tories of soda and ultramarine, and that competent 
English makers of these articles are sure to make their 
fortunes by establishing here. A part of the necessary 
capital could needs be found here. If this interests any 
of your readers I shall be happy to give details on 
enquiry." 

Our Weights and Measures. — A Pradlical Treatise 
on the Standard Weights and Measures in use in the 
British Empire, with some account of the Metric System, 
by H. J. Chaney, will be published early in January. It 
will contain much information derived from authorised 
sources, and the writer's position as Superintendent of 
the Standards Department, Board of Trade, assures us 
that the information given — information now for the first 
time published — will be of pradtical use to local officers, 
and especially to traders generally. It is hoped also that 
the book will even be of use to the chemist and physicist, 
and that the antiquarian will find something of interest in 
its pages. The information given with reference to 
" metric " weights and measures should be of particular 
use to scientific authorities and to manufadturers. 



MEETINGS FOR THE WEEK. 



Monday, i8th.— Society of Arts, 8. (Cantor Lectures). " Material 
and Design in Pottery," by Wm. Burton, F.C.S. 

Society of Chemical Industry, 8. " The Character 

of the London Water Supply," by W.J. Dibdin, 
F.I.C, F.C.S. 
Tuesday, igth.— Royal Institution, 3. " Animal Eleftricity," by 

Prof. A. D. Waller, F.R.S. 
Wednesday, 20th.— Society of Arts, 8. «' The Roller Boat of Mens. 

Bazin," by Emile Gautier. 
Thursday, 21st.— Royal Institution, 3. " Some Secrets of Crystals," 
by Prof. H. A. Miers, F.R.S. 

Chemical, 8. " Studies of the Properties of Highly 

Purified Substances — I. The Influence of Mois- 
ture on the Produftion of Ozone from Oxygen, 
and on the Stability of Ozone; II. The Be- 
haviour of Chlorine, Bromine, and Iodine with 
Mercury; III. The Behaviour QfCt^lorine under 



36 



Meetings for the Week, 



ICHBHICAt. NBWS. 
Jan. IS, 1897. 



the Influence of the Silent Discharge of Elec- 
tricity and in Sunlight," by W. A. Shenstone. 

•' "Adlion of Diastase on Starch," Part III., by 

A. R. Ling and T. L. Baker. " The Solution, 
Density, and Cupric Reducing Power of Dex- 

' trose, Levulose, and Invert-Sugar," by Horace 

}. Browne, F.R.S., G. Harris Morris, Ph.D., 
. H. Millar. " Derivatives of Maclunn," Part 
I., by A. G. Perkin. 
Friday, sjnd. — Royal Institution, 9. " Properties of Liquid Oxygen," 
by Prof. Dewar, F.R.S. 
^^, Physical, 3. "An Exhibition of some Simple Appa- 

ratus," by W. B. Croft, M.A. '• On the Passage of 
Elediricity through Gases," by E. C. Baly. 
SaTUKDAY, 23rd. — Royal Institution, g. '* Negledled Italian and 
French Composers/' by Carl Armbruster. 



Errata. — P. 14, col. i, line 23 from top, for " Potass. Nitrate " read 
"Potass. Nitrite." P. 15, col. 2, line 33 from bottom, /or "large 
amounts " read " larger amounts." 



WILLIAM F. CLAY, 

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ROYAL INSTITUTION OF GREAT BRITAIN, 

ALBEMARLE STREET, PICCADILLY, W. 

npUESDAY NEXTTTJanuary 19) at Three 

•*■ o'clock. Professor A. D. WALLER, M.D., F.R.S., Fullerian 
Professor of Physiology, First oi Twelve LeClures on "ANIMAL 
ELECTRICITY." One Guinea the course. 

THURSDAY (January 21) at Three o'clock. Professor HENRY 
MIERS, M.A., F.R.S. , First of Three LeCtures on "SOME 
SECRETS OF CRYSTALS." Half-a guinea. 

SATURDAY (January 23) at Three o'clock, CARL ARM- 
BRUSTER, Esq., First of Three LeCtures on "NEGLECTED 
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Subscription to all the Courses in the Season Two Guineas. 

FRIDAY EVENING (January 22nd) at Nine o'clock. Professor 
DEWAR, M.A., LL.D., F.R.S., on "PROPERTIES OF LIQUID 
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admitted. 

THE 

DAVY FARADAY RESEARCH LABORATORY 

OF 

THE ROYAL INSTITUTION. 



Directors : 

The Right Hon. LORD RAYLEIGH, M.A., D.C.L., LL.D.. F.R.5, 

Professor DEWAR, M.A., LL.D., F.R.S. 

Superintendent of the Laboratory : 

Dr. Alexander Scott, M.A., D.Sc. 

This Laboratory, which has been founded by 
Dr. LuDwiQ Mono, F.R.S., as a Memorial of Davy and 
Faraday " for the purpose of promoting original research in Pure and 
Physical Chemistry," will be opsn on the i8ih of January. 

Under the Deed of Trust, workers in the Laboratory are entitled, 
free of charge, to Gas, Electricity, and Water, as far as available, 
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Royal Institution. 



Mr. J. G. LORRAIN, M.I.E.E., M.I.M.E, M.S.C.I., 

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"PATENTEE'S HANDBOOK" Post Feee on application. 



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and Potash, in large or small quantities, and either solid 
or in solution, at ROBERT RUMNEY'S, Ardwick Chemical 
WsriES, Manefaeat:r. 



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DBOZR-A-CIC—Cryst. and powder. 

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S-A-IjICSTIjIO— By Kolbe's process. 

1?_A.Isri:snC— For Pharmacy and the Arts. 

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(Compressed in steel cylinders). 

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Chemical Mbw8» ) 
Jan. 22, 1897. I 



Manufacture of Calcium Carbide^ 



THE CHEMICAL NEWS. 

Vol. LXXV., No. 1939. 
TUNGSTEN HEXABROMIDE. 

By HERBERT A. SCHAFFER aud EDGAR F, SMITH. 

The most recent work upon tungsten bromides is that of 
Roscoe {Ann. Chem., Liebig, clxii., 362), who endeavoured 
to prepare a hexabromide, but obtained instead a penta 
derivative from which the dibromide was subsequently 
made. By reference to the literature bearing upon this 
subjeift it will be noticed that bromine, diluted with carbon 
dioxide, was made to &&. upon tungsten metal exposed to 
a red heat. Experimental evidence is at hand that 
tpngsten at high temperatures deoxidises carbon dioxide, 
thus allowing ample opportunity for the production of 
oxybromides, which, in spite of the greatest care, are 
sure to appear in larger or smaller amount. The thought 
also suggested itself that possibly the " red heat " at 
which the aftion was allowed to occur might have been 
detrimental and have indeed prevented the formation of 
the hexabromide. 

Hence, we determined to operate in an atmosphere of 
nitrogen and to apply a very gentle heat to the vessel 
containing the tungsten. In this connexion it may be 
mentioned that the nitrogen was conduced through a 
series of vessels charged with chromous acetate, sulphuric 
acid, caustic potash, and phosphorus pentoxide, respec- 
tively. It then entered an empty vessel, into which dry 
bromine was dropped from a tap-funnel, and after passing 
through a tall tower, filled with calcium chloride, entered 
a combustion tube resting in a Bunsen furnace. The 
anterior portion of the combustion tube was contracfted at 
intervals, forming a series of bulbs, and at its extremity 
was connedled with an empty Woulflf bottle, followed by 
a calcium chloride tower, and finally a receiver filled with 
soda lime and broken glass. A steady current of nitrogen 
was conduded through this system for a period of three 
days. On the fourth day bromine was introduced. The 
tungsten contained in the combustion tube was heated 
very gently. In a short time brown vapours appeared. 
These condensed to a liquid beyond the boat and eventu- 
ally passed into blue-black crystalline masses that sepa- 
rated from the walls of the tube, when perfedly cold, with 
a crackling sound. Very little heat was required to melt 
them, and they could with care be re-sublimed in distinft 
blue-black needles. The latter was colleded in one of 
the bulbs (No. 2) previously mentioned. Other produdts 
were observed and isolated. All were analysed. Bulb 
No. I— that nearest the tungsten metal— contained a 
black velvety compound, which upon analysis showed 
the presence of tungsten dibromide. Bulb No, 2 con- 
tained 0*2x03 grm. of the blue-black crystals, which 
yielded 0-0577 grm. of tungsten, or 27-43 per cent, and 
0"i543grin« of bromine, or 73-53 per cent. The theoretical 
requirements of tungsten hexabromide are 27 72 per cent 
tungsten and 72*28 per cent bromine. The bromine per- 
centage found is high. This may be due to traces of 
bromine that had not been driven out from the crystalline 
deposit, or to adherent silver tungstate, as some tungstic 
acid remained in the solution from which the silver 
bromide was precipitated. 

A fresh portion of the blue-black crystals was prepared 
as before and analysed. The bromine determination was 
unfortunately lost. The determination of the tungsten 
resulted as follows: — 0-4351 grm. of material gave 0*1222 
grm. of tungsten, or 2808 per cent, 

A third preparation was made. On subjedting 0*1775 
grm. of it to analysis these results were obtained : — 
0*0496 grm. tungsten or 27-94 per cent. 
0*1266 grm. bromine or 71*32 per cent. 



37 



Tabulating the series, we have :— 

Requijred 

for hexa- 

Found Mean, bromide. 

Per cent. Per cent. Per cent. Per cent. Per cent," 

Tungsten .. 2743 28-08 2794 27*81 27*72 

Bromine .. 73*53 71*32 — 72*33 72-2* 

These figures give evidence that the body analysed. is 
tungsten hexabromide. * 

In analysing the third portion of the blue-black needles 
the bromine was determined by placing the material in a 
small Erlenmeyer bulb, covering it with nitric acid and 
then distilling. The liberated bromine was passed into 
a silver nitrate solution. 

The tungsten hexabromide prepared by us consists, as 
already observed, of blue-black needles. Moderately 
elevated temperatures decompose the compound. It 
gives off fumes when brought in conta<a with the air. 
Water decomposes it with the formation of a royal-blue 
coloured oxide. Ammonia water dissolves it, the solution 
remaining colourless. A vapour density determination 
resulted negatively, as decomposition was apparent early 
in the experiment.— Frow the journal of the American^ 
Chemical Society, December, 1896. 



THE MANUFACTURE OF CALCIUM CARBIDE.* 

By J. T. MOREHEAD and G. de CHALMOT. 

(Concluded from p. 31), 

We have now still to consider a very important question, 
namely, how much coke and lime are necessary to produce 
one pound of carbide. The formation of carbide takin" 
place according to the following formula, — - 

CaO -f 3C = CO 4- CaC2, 
56 36 28 64 

0*563 pound of carbon and 0*875 pound of calcium oxide 
are theoretically necessary to yield one pound of carbide. 
The carbide of 5 cubic feet of gas per pound contains, 
however, free calcium oxide. We therefore might expeft 
that more calcium oxide and less carbon are used. In 
prcdlice, however, some calcium oxide and carbon are 
volatilised or burned. For a succession of experiments 
we have weighed the mixture that was put into the 
furnace and that which was taken out, and analysed 
both. We have experienced considerable trouble in 
weighing the red hot material accurately, and in obtaining 
fair samples. We have therefore not been able to observe 
as to how far the consumption of calcium oxide and of 
carbon is influenced by the circumstances that alter the 
quantity and quality of the produdt. We found, however, 
that less mixture is used if properly stoked, and if the arc 
is kept covered. We found also that the losses of 
carbon are always more considerable than those of cal- 
cium oxide. 

Table VIII. 
No. of ex- Mixture into the furnace. .Mixture out of the furnace, 
periment. CaO. C. CaO. C. 

Per cent. Per cent. Per cent. Per cent. 

5470 36-32 57*01 36*89 



2 54*5 1 

3 5623 

4 55 "66 

5 5970 

6 56-65 

7 55 44 

8 5064 

9 52*08 
10 4934 



34-18 
36*46 
36*51 

34*43 
36-09 
36-32 
34-43 
29*39 
3385 



57*29 
57 'oo 

55-47 
58-16 
55-60 

5493 
51-81 
52-09 
41*45 



3336 
35*62 
35*02 

32*94 
3261 
3109 
34*29 
28-90 
28-27 



* Read Sept. 3rd before the Springfield meeting of the A.A.A.S. by 
one of us (M ). We have made since then several additions, so as to 
make the article complete up to the present time. From the Journal 
of the American Chemical Society, April, 1896. 



38 



Derivatives of Columbium and Tantalum^ 



Number 


Amount of 


Amount of 


of experi- 


CaO put into 


C put into 


ment. 


the furnace. 


the furnace 




Lbs. 


Lbs. 


Z 


675 


448 


2 


739 


463 


3 


859 


557 


4 


612 


402 


i 


851 


491 


-.'r** 


go6 


577 


^'7 


1067 


699 


8 


552 


375 


9 


374 


211 


10 


675 


461 





Table VII. 






CaO obtained 


C obtained Amount 


Amount ProduAion 


Amount of 


from the 


from the of CaO 


of C of clean 


CaO per lb. 


furnace. 


furnace. used. 


used. carbide. 


of carbide. 


Lbs. 


Lbs. Lbs. 


Lbs. Lbs, 


Lbs. 


417 


270 258 


178 19s 


1-32 


415 


242 324 


221 285 


1-13 


601 


375 258 


182 190 


1-36 


415 


262 197 


140 190 


i'04 


498 


282 353 


209 280 


1-26 


478 


280 428 


297 375 


I-I4 


420 


238 647 


461 555 


1-17 


253 


167 299 


208 223 


1-34 


207 


115 167 


96 132 


1-27 


244 


134 431 


327 345 


1-25 






Average . . . . 


.. 1-228 



( Chemical News, 
I Jan. 22, 1897. 



Amount of 
C used per 
lb. of carbide ■ 

Lb. 

0*91 

078 

0-96 

074 

075 

079 

083 

095 

073 
0-95 
0-837 



The average figures of Table VII. are rather high, for 
where much coke and lime have been used this is cer- 
tainly partly due to losses of material by weighing into 
and out of the furnace, and also by insufficient stoking. 
In the King furnace, the under part of which shuts her- 
metically tight and excludes draught, and which is stoked 
mechanically, the amount of coke and lime necessary for 
making one pound of carbide will certainly be much 
reduced. In the figures given in Table VII. we have left 
the outside coating out of the calculation. In a plant 
where the acetylene gas is generated at once from the 
carbide it would pay to use this coating also for making 
gas. From Table VII. we see that a very large per- 
centage of the mixture is not aded on by the arc. We 
have, however, reduced this amount to one-third of the 
mixture, and could reduce it still more without either 
injuring the furnace, the quantity and quality of the 
carbide, and without increasing the amount of carbon and 
lime necessary for making one pound of carbide. In the 
furnace used in Spray the inside is square instead of 
©diagonal, and tlie dimensions are rather too large. We 
thereore feed more material into the furnace than is 
necessary. 

Besides coke we have used several other .carbonaceous 
materials for making carbide. We have used soft coal, 
anthracite, charcoal, pitch, tar, rosin, and asphalte, and 
obtained in all cases carbide. Most of these materials 
are not of sufficient importance to be taken into con- 
sideration, and we will only add some words about the 
first three. 

Charcoal, owing to its small percentage of ash, yields a 
very pure carbide. The only drawback, besides its price, 
is that it is so light that the gases carry it off to a con- 
siderable amount. It is therefore necessary to add from 
5 to 10 per cent more carbon to the mixture if charcoal is 
used than if coke is used. 

We used a soft coal which contained volatile matter 
19-84 per cent and ash 1-48. The mixture with soft coal 
gave a tenific blaze. The carbide was covered with a 
large amount of very porous slag, in which there was 
much graphite. The average of results of two runs are 
6-41 pounds per hoisepower in twenty-four hours and 
4-33 cubic feet of gas per pound, which equals 27-75 cubic 
teet of gas per horse-power in twenty-four hours. 

We used anthracite coal, which contained volatile 
matter 7-95 per cent and ash 4-02 per cent. We made 
two runs with slacked and two with unslacked lime. 
There was no appreciable difference in the use of slacked 
and unslacked lime. The average result of the four runs 
was 7-64 pounds per horse-power in twenty-four hours 
and 4-03 cubic feet of gas per pound, which equals 30 79 
cubic feet per horse-power in twenty-four hours. These 
results are much lower than those obtained with coke. 
We cannot therefore recommend the use of either 
anthracite or soft coal for making carbide. The su- 
periority of coke and charcoal over anthracite is probably 
due to the porosity of the former materials, which must 



facilitate the volatilisation of the carbon in the eledtric 
arc, which probably must precede the formation of 

carbide. 



DERIVATIVES OF COLUMBIUM AND 

TANTALUM.* 

By MARY ENGLE PENNINGTON. 

(Concluded from p. 34). 

Products obtained on Heating the Oxides of Tantalum 

and Columbium with Phosphorus Pentachloride. 
One-half grm. of columbic oxide was heated with 
phosphorus pentachloride, the quantity being calculated 
from the following equation : — 

Cb205-h5PCl5 = 2CbCl5-|-5POCl3. 

The experiment was conduced in a sealed tube from 
which all air had been expelled, the temperature being 
maintained at 180—200° C., for seven hours. The re- 
sulting mass was moist, and a dirty green. The tube 
was opened, conneded quickly with a small test-tube, 
and then heated in an air-bath. A small quantity of 
liquid distilled into the front part of the tube. This was 
a yellowish green, and gave with water a white precipi- 
tate, apparently a hydrated columbic oxide. 

At a higher temperature, about 200° C, yellow vapours 
coUedled in the cool portion of the tube. These settled 
on the glass as yellow, oily drops, and on cooling solidi- 
fied, long yellow needles being detected here and there. 
Nearly all of the substance in the tube, however, re- 
mained as the greenish mass, which had become dry. 
No change was observed on heating above 360° C. The 
tube was then wrapped in copper gauze and heated with 
a Bunsen lamp. The green substance swelled up, be- 
came white, iridescent, and almost filled the tube. No 
green colour remained. Analysis of this compound 
showed it to be columbium oxychloride, CbOCl3. The 
long yellow needles which had been observed in the front 
part of the tube changed gradually on heating, and be- 
came white and iridescent like the remainder of the 
substance. 

This behaviour indicated the formation of a penta- 
chloride which was then changed to oxychloride by the 
small quantity of air which entered the tube when it was 
connedled with the receiver. 

A second tube, heated for eight hours at 230—235° C, 
gave a dark yellow, semi-fluid mass. Great care was 
taken in this experiment to exclude all traces of mois- 
ture, and the distillation was condudled under reduced 
pressure. Phosphorus oxychloride in considerable quan- 
tity distilled over, leaving in the tube a yellow crystalline 

♦ From the author's thesis presented to the University of Penn- 
sylvania for the degree of Ph.D., 1895. From the Journ. Amer. 
Chem. Soc, xviii., January, 1896. 



Crrmical News, ) 
Jan. 22, 1897. ) 



Derivatives of Columbium and Tantalum, 



39 



substance, which, on treating with water, decomposed 
with hissing and an evolution of hydrochloric acid gas. 
This compound was analysed according to the method of 
Marignac [Ann Chim. Phys., viii., 5). The ignited oxide 
weighed o'5642 grm. As only i grm. of columbic oxide 
was used in the experiment, the contaminating substance 
was sought, and was found to be phosphorus. Two 
fusions with bisulphate were necessary /or the extradlion 
of this element. Phosphoric acid was also found in the 
filtrate from the pentoxide. 

The question now arose regarding the position of this 
phosphorus. Is there a compound formed containing 
columbium, phosphorus, and chlorine, or is the phos- 
phorus content due to an incomplete expulsion of the 
excess of phosphorus pentachloride ? 

Another experiment was therefore tried under the fol- 
lowing conditions :— One-half grm. columbium pentoxide 
was heated with the calculated quantity of phosphorus 
pentachloride at a temperature not exceeding 210° C. for 
eight hours. The tube contained a yellow mass as be- 
fore. It was placed in an air-bath and connedled with a 
chlorine generator, the receiver having been previously 
filled with chlorine. At 190° C. a very volatile substance 
colledled in the front part of the receiver. This was a 
lemon yellow, and, when analysed, gave i5"85 per cent 
columbium and 6-095 P^r cent phosphorus. 

At 190 — 200° C, long yellow needles colleded ; some 
of these were nearly half an inch in length. Analysis 
gave 27'37 per cent columbium and 32'i9 per cent 
phosphorus. 

The substance, which did not volatilise at 200° C, 
was brownish-yellow, and apparently crystalline. Analysis 
gave 28*11 per cent columbium, and 1*34 per cent phos- 
phorus. 

In none of these analyses could the chlorine content be 
determined, because of the violence with which water ads 
upon the compounds, resulting invariably in the loss of 
some hydrochloric acid. 

It seemed probable that the brownish-yellow residue in 
the tube was columbium pentachloride, enclosing a small 
quantity of phosphorus pentachloride. To determine all 
three elements, the following method was used: — 

The more volatile compounds having been removed by 
distillation in a stream of chlorine gas, the residual 
substance was quickly weighed and thrown into a dilute 
solution of silver nitrate. The precipitate of silver 
chloride, silver phosphate, and hydrated columbic oxide 
was then filtered, and washed on the filter with dilute 
nitric acid. The phosphoric acid obtained was deter- 
mined by a magnesium mixture. Dilute ammonium 
hydroxide was then poured over the mixture of silver 
chloride and columbic oxide. It was found that all the 
silver salt could not be removed by this means. The 
mixture was therefore transferred to a porcelain crucible 
and reduced in a stream of hydrogen gas, the metallic 
silver being dissolved out with dilute nitric acid, then 
precipitated as chloride. The columbium remained in 
the form of a violet compound, which, on ignition in the 
air, went over to pentoxide. 

A small quantity of phosphorus was obtained, which 
was calculated into pentachloride and deduced from the 
material taken. 

Rose states that a columbate of silver, CbaOs.AgaO, 
is formed on the addition of silver nitrate to a solution 
of sodium columbate. As, upon the addition of water 
to columbium pentachloride, an almost perfedl solution 
is produced for a few moments, the columbium in solu- 
tion may combine with the silver. In such a case the 
silver chloride finally weighed would represent both the 
silver in combination with chlorine and that with 
columbium. 

The analytical results are as follows: — 
Substance taken = 0"89i7 grm. 
Phosphorus found = 0*02596 grm. 
This, as phosphorus pentachloride, requires 0-14829 grm. 
of chlorine. 



Substance taken minus PCl5 = 07i75 grm. 
Columbium found = 0*2485 grm. 
Columbium required = 0*2484 grm. 
Chlorine found = 0*66509 grm. 

Taking from this 0*14829 grm. of chlorine, which is in 
combination with phosphorus, we have ch]orine = o-5i68 
grm. ; columbium pentachloride requires 0*4691 grm. Cal- 
culating the quantity of silver which, according to Rose's 
formula, would combine with the amount of columbium 
oxide found, and deduding the chlorine corresponding 
to it, 0*4699 grm. of chlorine is found to be in combination 
with the columbium. 

The volatile compounds mentioned above were re- 
calculated into phosphorus pentachloride and columbium 
pentachloride. It was found that, by removing the phos- 
phorus as pentachloride, satisfactory analyses for colum- 
bium pentachloride were obtained from the residues. 

Tantalic oxide was also heated with phosphorus penta- 
chloride, the same conditions being maintained as in the 
columbium experiments. A yellow mass was formed, 
lighter in colour than the columbium compound, and only 
slightly moist. The tube was placed in an air-bath, and 
distilled at a temperature not exceeding 245° C. This 
distillation was conduded under reduced pressure. A 
small quantity of phosphorus oxychloride distilled over, 
and in the front part of the tube a little phosphorus penta- 
chloride colleded. The tantalum compound remaining 
was light yellow, dry, and powdery — apparently amor- 
phous. It combined with water with hissing, liberating 
tantalic oxide, which contained no phosphorus. A small 
quantity of this element was found in the filtrate from 
the oxide. It was calculated into phosphorus penta- 
chloride, and deducted from the total quantity. 

Weight of substance taken = 0*6700 grm. 
Weight of tantalum found = 0*3389 grm. 
Required tantalum = 0*3391 grm. 

Tantalum pentachloride is, therefore, formed when 
tantalic oxide is heated with phosphorus as penta- 
chloride. 

Reduction of the Compounds of Columbium and Tantalum 
to Metal, 

Two experiments aiming at the preparation of colum- 
bium and tantalum in the metallic state have been tried 
during this research, and I regret exceedingly that lack of 
time has prevented a more careful study of the reactions 
obtained. It is my intention to go more deeply into the 
subjedt than I have been able to do. 

Experiment i. — An iron cylinder, 3 inches in diameter, 
having an inch bore, was charged in the following man- 
ner: — First, a layer of dry salt, then a layer of metallic 
sodium, above which were placed about 7 grms. of 
potassium tantalum fluoride, this being followed by 
another layer of sodium. The cylinder was then tightly 
packed with dry salt, and a heavy lid screwed on. It 
was then placed in a wind furnace, the temperature of 
which was comparatively low. In less than one half-hour 
it was found that the cylinder had melted down, and no 
trace of the charge could be found. 

Experiment 2. — Marignac obtained an alloy of colum- 
bium and aluminum by heating the potassium double 
fluoride with aluminum scales in a carbon crucible. In 
the experiment to be described columbic oxide was used, 
salt and cryolite being employed as a flux. The following 
layers were placed in a graphite crucible: — 

1. Salt. 

2. Cryolite. 

3. Aluminum clippings. 
/ 4. Columbic oxide. 

5. Aluminum clippings. 

6. Cryolite. 

7. Salt. 

The proportion of these substances used were: — 



4'o Determination of Atomic Masses by the Electrolytic Method. 



I CHBUICAL NBWS) 

I Jan. 22, 1807. 



2 parts CbaOs. 
10 parts cryolite. 
15 parts aluminum. 

X parts sodium chloride. 

The graphite lid was firmly luted on with fire-clay, the 
crucible was buried in a wind furnace which was kept at 
a white heat for eight hours. At the end of this time it 
was found that the graphite crucible had been severely 
attacked. It .was reduced to a shapeless mass, but on 
breaking a powdery substance was found, in which were 
contained many little metallic buttons varying in size 
from a large pea to those of microscopic proportions. 
These were carefully picked out, and various reagents 
tried upon them. 

Single acids do not attack them. Aqua regia makes a 
■slight impression on long heating. Fusion with bisul- 
phate affords only a partial decomposition. The substance 
is exceedingly light; it is dark grey, and does not alter in 
the air. A partial oxidation occurs after prolonged heating 
in the air. The substance is not brittle. 

Summary. 
I. The decomposition of columbite is more readily and 
satisfaiflorily accomplished by the Gibbs than by the bi- 
sulphate method. This method is also more valuable for 
the preparation of large quantities of pure oxides. 
- 2. The qualitative rea(5lions of columbium, tantalum, 
and titanium, when existing as double fluorides, are not 
the same as when the metals exist as tantalates, colum- 
bates, and titanates. 

3. The adtion of the eledric current upon tantalum and 
columbium double fluorides gives a lower hydrated oxide. 
The precipitation is not complete. 

4. It was hoped that in preparing the double fluorides 
of columbium, tantalum, and titanium with rubidium and 
caesium, a difference in solubility of the salts would be 
found which would afford a better separation of these 
metallic oxides under discussion. This hope has not been 
realised. 

5. Heating the oxides of columbium and tantalum in 
sealed and vacuous tubes with phosphorus pentachloride 
yields the pentachlorides of these metals and phosphorus 
oxychloride. 

I take pleasure in acknowledging the kindness shown, 
and the interest taken in the preceding work, by Dr. 
Edgar F. Smith, of the University of Pennsylvania, in 
whose laboratory it was carried out. 



DETERMINATION OF THE ATOMIC MASSES 

OF SILVER, MERCURY, AND CADMIUM, 

BY THE ELECTROLYTIC METHOD.* 

By WILLETT LEPLEY HARDIN. 

(Continued from p. 29). 

First Series. 
Experiments on Silver Nitrate. 
The nitrate of silver seems to fulfil the conditions neces- 
sary for accurate analyses, inasmuch as it is stable and 
crystallises in well-defined crystals, which can be fused 
without decomposition. 

Preparation of Silver Nitrate. 
The material used in these experiments was prepared 
by dissolving pure silver in pure aqueous nitric acid in a 
porcelain dish. An excess of silver was used, and after 
complete saturation the solution was poured off from the 
metal into a second dish, and evaporated to crystallisa- 
tion. The perfeftly transparent rhombic plates of silver 

♦ Contribution from the John Harrison Laboratory of Chemistry 
No. 13. From the author's thesis presented to the Faculty of the 
University of Pennsylvania for the degree of Ph.D. — From the 
Journal of the Ameiican Chemical Society, xviii., p. 990. 



nitrate which separated were dissolved in pure water and 
re-crystallised. The crystals were then carefully dried, 
placed in a platinum crucible which rested in a larger 
platinum dish, and gradually heated to fusion. After 
cooling, the perfedlly white opaque mass was broken up 
and placed in a ground-glass stoppered weighing-tube, and 
kept in a desiccator in a dark place. 

Mode of Procedure. 
The platinum dish in which the deposit was made was 
carefully cleaned with nitric acid and dried to constant 
weight. It was then placed in a desiccator over anhy- 
drous calcium chloride, and this, together with the desic- 
cator containing the tube of silver nitrate, was placed in 
the balance room, where they were allowed to remain 
until their temperatures were the same as that of the 
room. After weighing the platinum dish, the tube of 
silver nitrate was weighed and part of the salt removed 
to the dish, after which the tube was re-weighed. The 
difference in the two weighings, of course, represented 
the weight of silver nitrate used in the experiment. 
Enough water to dissolve the nitrate was added to the 
dish, and then a solution of potassium cyanide, made by 
dissolving 75 grms. of pure potassium cyanide in i litre 
of water, was added until the silver cyanide first formed 
was completely dissolved. The dish was then filled to 
within a quarter of an inch of the top with pure water, 
and the solution eledrolysed with a gradually increasing 
strength of current. The following Table will show the 
strength of current and the time through which itadled:— 
Time of aiftion. Strength of current. 

2 hours.. .. N.Dioo=o 015 amperes. 
4 i» •• .. N.Dioo=o-o30 „ 
6 „ .. .. N.Dioo = oo75 „ 
4 i> •• .. N.Dioo = o*i50 „ 

4 N.Dioo = o'40o „ 

By gradually increasing the strength of current in this 
way the silver came down in a dense white deposit. 
When the deposition was complete, before interrupting 
the current, the liquid was syphoned from the dish, pure 
water being added at the same time. This was continued 
until the cyanide was completely removed. The dish 
with the deposit was washed several times with boiling 
water, and carefully dried. It was then placed in a desic- 
cator, and allowed to remain in the balance room until 
its temperature was the same as that of the room, when 
it was re-weighed. 
Weight of platinum dish = 7i'27302 grms. 
Weight of silver nitrate = o'siigS grm. 
Temperature, 22°. 
Barometric pressure, 770 m.m. 
Weight of platinum dish + silver deposit = 7i'47io4 

grms. 
Temperature, 22°. 
Barometric pressure, 760 m.m. 
Density of silver nitrate = 4'328. 
I) brass weights = 8'5. 

M platinum dish = 21-4. 

t» metallic silver = 10*5. 

It atmosphere at the time of weighing the 

empty dish and silver nitrate = o*ooi2i2. 
I, atmosphere at the time of weighing the 

platinum dish -f- silver deposit = o'ooiigS. 
Computing on this basis we have the following : — 



o'BiigSl I + 



0'00I2I2 
T328 



5I2\_ 



71*27302 



1 + 



8-5 
AgN03 in vacuo. 

0'00I2I2 0*00I2I2 — 



0*31202 ss weight of 



21*4 



8-5 



i-l- 



o'Ooiig6 0*001 ig6 



21*4 



8-5 _ 



= 7i*272gi = wt.of 



platinum dish at 22° and 760 m.m. 



Crbuical NbW8, ) 
Jan. 22, 1897. ) 



London Water Supply. 



41 



7X '47104 -71*27291 = 0*19813 = weight of deposit at 22° 
and 760 m.m. 



0*i98i3( I + 



0*001196 o'onitg6 



)= 



0*19812 = weight of 



10*5 8*5 

deposit in vacuo. 
Taking = i6 and N = i4*04, the atomic mass of silver 
_ 0*I98T2 X 62 04 
(31202 — 19812} 

Ten observations on silver nitrate computed in the 
foregoing manner are as follows : — 



= 107-914. 





Weight 


Weight Atomic mass 




of AgNOa. 


of Ag. 


of silver. 




Grms. 


Grm. 




I 


0*31202 


0*19812 


107-914 


2 


0*47832 


0-30370 


107-900 


3 


0*56742 


036030 


107-923 


4 


0-57728 


036655 


107-914 


5 


0-69409 


0-44075 


107-935 


6 


0*86367 


0-54843 


107932 


7 


o-868ir 


0*55130 


107-960 


8 


o*937»6 


059508 


107-924 


9 


1-06170 


0-67412 


107907 


10 


I -19849 


0-76104 


107-932 




Mean .. 


.. = 107-924 






Maximum 


. . = 107-960 






Minimum 
Difference 


= 107-900 






= 0*060 






Probable error = + 0-005 





Computing the atomic mass of silver from the total 
quantity of material used and metal obtained, we have 
107-926. 

(To be continued). 



INTERNATIONAL EXHIBITION AT BRUSSELS' 
1897. 

The rage for those displays known as " international 
expositions " still continues. Regardless of the fadl that 
few persons are benefitted by such gatherings, except 
railways, hotel proprietors, and the small but noisy class 
who might be called professional exhibitionists, most 
States still think it their duty or their policy to challenge 
the world to an industrial competition. This season 
Belgium holds the arena. Its Exhibition will include a 
sedtion of the Sciences divided into the following seven 
classes: Mathematics and astronomy, physics, chemistry, 
geology and geography, biology, anthopology, and biblio- 
graphy. Participators will have nothing to pay for space, 
and will have to pay reduced freights for the conveyance I 
of their exhibits. | 

We cannot, however, here refrain from reminding our- | 
selves that any and every advance or improvement in 
any science will not fail to have become known to the 
world through the scientific and technical press, so that the 
communications and exhibits at such gatherings will have 
lost much of their novelty. We have much pleasure in 
admitting that there is here no class for political economy, 
which, whenever tolrtated, slides inevitably into party 
politics with its usual amenities. The Belgian Govern- 
ment proposes a series of questions, and offers for the best 
solutions prizes amounting to the modest aggregate of 
20,000 francs. Pamphlets giving full particulars may be 
obtained on application to the General Commissariat of 
the Government, at 17, Rue de la Presse, Brussels. 

Among the problems to be solved in the chemical class 
must be mentioned — 

To establish the constitution of camphor by means of 
reaiftions, both analytical and synthetic, to differentiate 
the optical isomers by means of new chemical readions. 



A practical method for transforming without great 
expense atmospheric nitrogen into ammonia. 

A practical method for the preparation of chlorine from 
CaCl, more economical than those already in use. 

A new process for fixing the azo>colourupon the various 
textile fibres preferable to those hitherto known. 

The acid HI being not easy to prepare, to find an 
essentially pradical method for its produdlion. 

An improvement in the procedures of fradtibnated dis* 
tillation. 

Under biology there is the demand for new researches 
of living beings by means of the X rays. 



LONDON WATER SUPPLY. 
Report on the Composition and Quality of Daily 
Samples of the Water Supplied to London 
FOR THE Month Ending Decembeb 3ist, 1896. 

By WILLIAM CROOKES, F.R.S., 

and 

PROFESSOR DEWAR, F.R.S. 



To Major-General A. De Courcy Scott, R.E., 
Water Exatniner, Metropolis Water Act, 1871. 

London, January iitb, 1897. 
Sir, — We submit herewith, at the request of the 
Diredors, the results of our analyses of the 175 samples 
of water colledled 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 Dec. 1st to Dec. 3i8t 
inclusive. The purity of the water, in respedl to organic 
matter, has been determined by the Oxygen and Com- 
bustion processes; and the results of our analyses by 
these methods are stated in Columns XIV. to XVIII. 

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

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

Of the 175 samples examined all were found to be clear, 
bright, and well tiltered. 

Rain has fallen at Oxford on almost every day during 
the month, there being but nine days when none was 
recorded ; the average tall for the month of December is 
2'io inches, the adual fall this month has been 3*13 inches, 
giving an excess of 1-03 inches. The deficiency for the 
whole year amounts to 3*53 inches, or 13-3 percent, on a 
thirty years' average of 25*72 inches. 

The details of the raintali are shown in the following 
table :— 

Rain/all in Inches at Oxford, Month by Month, during 
the Year 1896. 





Aaual 


Mean of 


Difference from 




fall. 


30 years. 


the 


mean. 


January .. 


0*63 


2*16 


- 1-53 


— 


February .. 


0*36 


1-76 


— 1*40 


— 


March 


2*45 


1-50 


— 


+ 0-95 


April .. 


0*58 


1-66 


-1*08 


— 


May .. .. 


020 


1-83 


-1*63 


— 


June .. .. 


2-42 


2-11 


— 


+ 0*031 


July .. .. 


1-40 


2-68 


-1*28 


— 


August 


2*01 


2*32 


-0-31 


— 


September. 


. 5-47 


2*43 


— 


+304 


Oaober . 


2-85 


2*75 


— 


+0*10 


November. 


0-79 


2-42 


-1*63 


— 


December.. 


3-13 


2*10 


— 


+ 1*03 



22*29 25*72 -8'86 +5"43 



42 



Examination of the Products of Starch Hydrolysis. { 



ChbuicalNbws 

Jan. 22, iSq7. 



Month. 

January 
February 
March . • 
April .. 
May .. 
June . . 



July .. 
August . 
September 
Odlober 
November , 
December , 



Thames, 

unfiltered. 

1824 

1453 
2160 

1833 
I30I 
2081 



Five Thames- 
derived Companies 
filtered. 
36 
26 

41 
33 
21 

32 



New River 
unfiltered. 
1525 
1368 
1938 
150I 
950 
836 



New River 
filtered. 

31 
29 
27 
17 
25 

35 



River Lea, 
unfiltered. 

2005 

II09 

1900 

1643 

I216 

1729 



River Lea 

(East London), 

filtered. 

24 

28 

29 

34 
73 
28 



177s 


31 


1353 


27 


1600 


36 I 


2731 


21 


1886 


22 


2859 


33 


"33 


17 


361 


3 


537 


5 


1331 


II 


709 


4 


1642 


H 


2691 


19 


671 


4 


742 


14 


2223 


21 


1054 


20 


1178 


6 


4613 


60 


2729 


57 


1825 


15 



36 Mean of zst 6 months. 



2453 24 1235 18 1464 14 Mean of 2nd 6 months. 

2114 27 1294 22 1532 25 Mean of 12 months. 



It will be seen that the large excess of 3*04 inches in 
September has been mainly instrumental in reducing a 
deficiency which was becoming very serious. 

Our bafleriological examinations of the waters during 
the month of December give the following results :— 

Colonies 
per c.c. 

Thames water, unfiltered 4613 

Thames water, from the clear water wells of 

the five Thames-derived supplies., highest 248 

Ditto ditto lowest 6 

Ditto ditto .. {13 samples) mean 60 

New River water, unfiltered 2729 

New River water, from the Company's clear 

water well 57 

River Lea water, unfiltered ' .. 1825 

River Lea water from the East London Com- 
pany's clear water well 15 

The accompanying table shows the bacterial variations 
during the year. 

These results show that, taking the whole year's 
badteriological examinations, the high efficiency of the 
filtration and the excellent charadter of the London waters 
have been uniformly maintained. 
We are, Sir, 

Your obedient Servants, 

William Crookes. 
James Dewar. 

J ■ ' ■ ■ ■ ■ -'-•■ — 

PROCEEDINGS OF SOCIETIES. 



CHEMICAL SOCIETY. 
Ordinary Meeting, December ijth, 1896. 

Mr. A. G. Vernon Harcourt, President, in the Chair. 

Messrs. Alexander Scott, Frederick B. Power, W. W. 
Cobb, and Claude M. Thompson were formally admitted 
Fellows of the Society. 

Certificates were read for the first time in favour of 
Messrs. Alfred Cartmell, Alexandra Road, Burton-on- 
Trent ; William Diamond, Pye Bridge, Alfreton ; William 
Buckland Edwards, 5, Garlinge Road, Brondesbury, N.W.; 
Vaughan Harley, M.D , 25, Hariey Street, W. ; Fred 
Ibbotson, B.Sc, g, Melbourn Road, Spring Vale, Shef- 
field ; David Smiles Jerdan, M.A., B.Sc, 68, Union Street, 
Greenock ; Edward Rosling, Melbourne, Chelmsford ; 
Henry Potter Stevens, B.A., 14, Lower Sloane Street, 



Chelsea, S.W., Harry Thompson, Walton House, West 
Parade, Anlaby Road, Hull. 

The certificate of the following candidate, recommended 
by the Council, under Bye-law I., par. 3, was also read : — 
Jyoti Bhusan Bhaduri, Presidency College, Calcutta. 

Of the following papers those marked • were read : — 

•165. " On the Experimental Methods employed in the 
Examination of the Products of Starch-hydrolysis by 
Diastase." By Horace T. Browne, F.R.S., G. Harris 
Morris, Ph.D., and J. H. Millar. 

The paper is divided into the following sedlions : (i) the 
determination of solids from solution-density ; (2) deter- 
mination of specific rotary power ; (3) the relation of 
[o]jto [o]d; (4) determination of cupric reducing power; 
(5) limits of accuracy of the methods. 

The authors state that this account is a preface to a 
series of papers dealing with the question of starch- 
hydrolysis, and is a critical review of the experimental 
methods which have been employed by different observers 
who have approached this subjedt. An attempt has also 
been made to remove the misunderstanding which still 
exists as to the relations of the different systems of 
notation. 

The determination of the total solids from the density 
of the solution by the employment of the "divisor" 
method admits of great accuracy if the solution-densities 
of the pure substance have been previously determined. 

The " divisors " at varying concentration have been 
determined for cane sugar, maltose, dextrose, levulose, 
soluble starch, and the mixed products of starch-hydro- 
lysis of various grades, and the results have been plotted 
out in the form of curves whose equation is given in 
each case. The pure substances used in construding 
these curves were dried in a vacuum over phosphoric 
pentoxide at temperatures from 100° to 130°. 

For mixed starch hydrolytic produfls the divisor for 
equal concentrations increases with the specific rotatory 
power, and in such a regular manner that when the value 
of R is known, the divisor at any given concentration can 
be calculated. From the relation wJiich this divisor bears 
to the divisor of the apparent maltose present in the 
mixed hydrolytic produds, it is deducible that the divisor 
for the amylin constituent is constant for equal con- 
centrations, even in starch produds of very different 
grades of hydrolysis. 

In the sedion on specific rotary power, the methods of 
exadl determination are discussed, and the relations of [«];, 
[«]j3'86, and [a]D are defined for substances of equal dis- 
persive power. As the dispersive power of cane sugar is 
sensibly different from that of dextrose and starch hydro- 
lytic produdls obtained by diastase, the factors for the 



^'"".'afisgT''} Action of Hydrogen Peroxide ^ &c., on Cobaltous Salts, 



43 



conversion of [a]j into [a]D are not identical in these 
cases. Much confusion of these relations has also been 
introduced by the unrecognised fadl that [a]j has been 
referred to two distinct rays in the yellow of different 
refrangibility. 

The cupric-redudtion of maltose and of the produdls of 
starch transformation is constant only when the con- 
ditions of experiment are identical. These are exadlly 
defined for the authors' method of procedure, and the 
reducing values are given in tabular form, and are com- 
pared with those of other observers. 

*i66. " On the Specific Rotation of Maltose and of 
Soluble Starch." By Horace T. Brown, F.R.S., 
G. Harris Morris, Ph.D., and J. H. Millar, 

The authors' determinations of the specific rotatory 
power of maltose at a temperature of i5'5° do not confirm 
the statement of Meissl that the values of [ajo vary with 
the concentrations between 2 and 20 per cent, but con- 
firm the general statement of Ost that between these 
limits the specific rotatory power is constant. At higher 
concentrations than 20 per cent the specific rotatory 
power diminishes slightly. 

The aftual results point to a value of [a]D = i37'93°, 
which is sensibly greater than Ost's value of i37'46'' at 

i5-5°- 

This discrepancy is due to the fadl that Ost employed 
weighed quantities of hydrated maltose which had been 
dried in a desiccator over sulphuric acid. The authors 
find that even after six weeks' drying in this manner, 
hydrated maltose contains 0*46 per cent more water than 
corresponds to CizHaaOn'HjO. If Ost's numbers are 
correded for this they give values, up to 20 per cent con- 
centrations, of [a]D = i38'i2° at I5'5°, a result almost 
exadtly identical with that of the authors. 

The specific rotatory power of soluble starch for con- 
centrations of 2*5 to 4*5 per cent is at I5'5°, [a]D = 202'o°. 

*i67. "On the Relation of the Specific Rotatory and 
Cupric-reducing Powers of the Products 0} Starch-hydro- 
lysis by Diastase." By Horace T. Brown, F.R.S. , 
G. Harris Morris, Ph.D., and J. H. Millar. 

When starch is transformed by diastase, a certain 
relation is always found to subsist between the cupric 
redudion and specific rotatory power of the hydrolytic 
produdls. This relation can be expressed in such a 
manner as to be entirely independent of any view we may 
hold as to the true nature of the transformation produds, 
and it is of so exadl a nature that if one property is known 
the other can be predidted with certainty. This is true 
not only for the mixed hydrolytic produdls, but for any 
fractionated portion of them. 

The authors regard this faft as lying at the root of the 
whole question of starch hydrolysis, and, as it is still not 
admitted by most continental workers, they bring forward 
a large amount of fresh evidence which they regard as 
absolutely conclusive. 

The results of the examination of 70 different starch 
transformations are given, some of them mixed produdls, 
others fraAionated produds, the specific rotatory and 
cupric-reducing powers being given in the various nota- 
tions in use. When the experimental results are plotted 
on a system of redangular co-ordinates, the degrees of 
specific rotation between soluble starch and maltose being 
represented on the line of ordinates, and the cupric 
reducing powers from soluble starch to maltose on the 
line of abscissae, the values all fall pradtically on a straight 
line joining the points of intersedion of the co-ordinates 
corresponding to the optical and reducing properties of 
soluble starch and of maltose respedively. 

The properties of soluble starch being R = o, [o]d = 202°, 
and of maltose, R= 100 and [a]D = i38'o°, then the rela- 
tion of specific rotation and cupric redudlion for any 
mixture or fradionation of the starch-hydroiytic produds 
will be expressed by I.a]D = 202- 0-64 R. 

The differences in the calculated and observed values 



for the 70 cases of hydrolysis examined are given, and are 
shown to be very small indeed. 

The authors have examined the published results of 
C. J. Lintner and of Ost, both of whom have denied the 
existence of any relation between [a]D and R, and find 
that, when rightly interpreted, they, for the most part, 
stridtly conform to the law of relation expressed above. 

Discussion. 

Dr. Armstrong, after commenting on the value of the 
information brought under the notice of the Society by 
Mr. Horace Brown and his co-workers, and on the 
remarkable accuracy with which starch could now be 
estimated, expressed the hope that it would be possible 
ere long to determine what really took place when starch 
was hydrolysed; he thought it was time that we should 
no longer be content merely to determine certain analytical 
fadors; we ought rather to seek for chemical methods 
which would render it possible to separate and isolate the 
produdls. 

Mr. A. R. Ling asked what value the authors found 
for the cupric reducing power of maltose when Wein's 
method was used. 

Dr. G. H. Morris, in reply, said that they found that 
Wein's tables give results about 5 per cent too low when 
the cupric redudlion of maltose is estimated by Wein's 
method, and the copper obtained calculated into maltose 
by the table ; in other words, perfedly pure maltose gives 
R = 95 — 96 instead of 100. 

•168. " The Action of Hydrogen Peroxide and other 
Oxidising Agents on Cobaltous Salts in presence of Alkali 
Bicarbonate." By R. G. Durrant, M.A. 

Similar green solutions may be obtained by adding 
hydrogen peroxide, sodium hypochlorite, chlorine, bromine, 
or ozone to cobaltous salts in presence of alkali bicar- 
bonates— or by adding a cobaltous salt to the anode of 
previously eledlrolysed potassium carbonate. 

The green colour is not destroyed by excess of cold 
acetic acid, but is rendered rather bluer in tint. This 
acetic solution is reduced by hydrogen peroxide. 

The evidence so far obtained shows (i) that the cobalt 
is in the " cobaltic state." This is proved by the 
results of three volumetric methods — in which 
standard sodium hypochlorite, hydrogen peroxide, 
and sodium sulphite are respedlively employed— green 
precipitates, produced from the green solutions, gave 
results showing that the available oxygen closely 
approximates to that to be expeded from cobaltic 
hydrate, 

(2) That the green colour of the solutions and of the 
precipitates appears not to be due to a particular 
alkali, since (i.) identical tints were obtained with 
the five different alkali bicarbonates, (ii.) potassio- 
cobaltic nitrite gives no green colour with bicar- 
bonates, (iii.) green precipitates washed free from all 
alkali, and digested with cold weak acetic acid, give 
green filtrates. 

(3) That carbon dioxide is necessary both for the 
formation and preservation of the green colour. The 
green colour of the acetic solution remains only so 
long as carbon dioxide is present. The green pre- 
cipitates (free from alkali) retain carbon dioxide so 
long as they remain green, and lose it when they 
become brown. It is, therefore, possible that the 
green cobaltic compound is of the nature of a car- 
bonate. 

Discussion. 

Several speakers, including the President, expressed 
the view that whilst the author had made it clear that 
the green substance was a cobaltic compound, further 
proof was needed of the suggestion that the salt formed 
was a cobaltic carbonate. 

Dr. Rideal mentioned that sodium peroxide, as well as 
hydrogen peroxide, gave rise to the green colour, pro- 
vided that an alkali bicarbonate was also present. 



44 



Ditneikytketohexamethylene, 



i CBBhlCAL NbWS, 
\ Jan. 22, 1807. 



Dr. Armstrong said that he would like to give expres- 
sion to the opinion that the time was come to determine 
what should be their course of aiSlion with regard to the 
publication of the discussions that took place at the meet- 
ings ; of late there had been an almost entire absence 
from the Proceedings of reports of the remarks made in 
the room, although these had often been of a nature 
which made it desirable that they should be brought 
under the notice of the Fellows generally. If the secre- 
taries could not undertake the work, steps should be 
taken to procure a proper report. Personally he had had 
no difficulty in obtaining reports during the nine years in 
which he had charge of the Proceedings, and he did not 
believe that there would be any difficulty. Without such 
reports the Proceedings were of little value. 

Professor Dijnstan said that Fellows attending the 
meetings were aware that it was not often that a compre- 
hensive discussion foUov/ed the reading of an ordinary 
paper. All important remarks and suggestions made at 
the meetings had been recorded in the Proceedings, and 
although no attempt had been made to record everything, 
and there might occasionally be room for difference of 
opinion as to what was important, he was always glad 
to receive from speakers, after the meeting, reports of 
their remarks, which he believed had been in nearly every 
case inserted in the Proceedings. He had, however, not 
thought it desirable to print Dr. Armstrong's remarks, 
of the omission of which Dr. Armstrong now complained, 
made on two recent occasions, proposing to record the 
time occupied by readers of papers. The method adopted 
by the speaker's predecessor in office in reporting dis- 
cussions had given rise to much dissatisfaiflion. If the 
present plan was not thought sufficient, then a shorthand 
report of the discussions could be taken. As a matter of 
fadt, however, the main value of the Proceedings lies in its 
beingthemeansof bringingat an earlydateunderthe notice 
of the Fellows, not merely remarks and suggestions made 
at the meetings, but concise abstradls of the papers read, 
the full publication of which could not take place in the 
Journal until much later. 

The President remarked that if a full report of the 
proceedings were considered desirable, its preparation 
could not be included in the duties of the Honorary 
Secretaries. He was disposed to think, however, that if 
It were generally known that the Secretaries were ready 
to receive from speakers after the meeting a few sentences 
giving the substance of their remarks, that this would 
meet the case in nearly every instance. 

169. •• Electrical Conductivity of Diethylammoniiim 
Chloride in Aqueous Alcohol." By James Walker, 
Ph.D., D.Sc, and F. J. Hambly, F.I.C. 

The authors have determined the condudlivityof diethyl- 
ammonium chloride dissolved in pure water, and in lo'i, 
30*7, 49'2, 72*0, 90"3, and 99*0 per cent alcohol, by volume, 
at dilutions ranging from 10 litres to 8000 litres. Tables 
and curves have been constructed, showing the variation 
of the molecular condudlivity and the degree of dissocia- 
tion with varying dilution and varying proportions of 
alcohol. 

170. " Formation of Substituted Oxytriazoles from 
Phenylsemicarbazide.'" By George Young, Ph.D., and 
Henry Annable. 

The adtion which takes place when a mixture of phenyl- 
Bemicarbazide and benzaldehyde is oxidised, has been 
re-investigated, and the views expressed by one of the 
authors in a previous paper {Trans., 1895, Ixvii., 1063) 
have been confirmed. The following aldehydes yield 
oxytriazoles by this adtion : metanitrobenzaldehyde, 
paranitrobenzaldehyde, metatoluic aldehyde, terephthalic 
aldehyde, cinnamic aldehyde. 

The authors have failed to obtain oxytriazoles from 
formaldehyde, acetaldehyde, paraldehyde, isobutyric 
aldehyde. 

- 171. " a-Bromocamphorsulpholactone.^' By C Revis 
and F. .Stanley Kipping, Ph.D., D.Sc. 



When obromocamphor is treated with anhydrosuK 
phuric acid, or with chlorosulphonic acid, it is converted 
into o-bromocamphorsulphonic acid {Trans., 1893, Ixiii., 
548). In the course of some experiments on the pre- 
paration of this sulphonic acid, it was found that when 
70 per cent anhydrosulphuric acid is added to a solution 
of a-bromocamphor in chloroform, the produdt consists, 
to some extent, of a crystalline compound which is 
insoluble in water. 

This substance has the composition CioHi3BrS04 
(found C = 38-8, H = 4'3, Br=25i, S = 9'7 per cent.; 
calculated C = 39"o, H = 4'2, Br = 25 8, S=io'3 per cent). 
It appears to be a bromocamphorsulpholadlone, and its 
formation is doubtless due to the oxidation of hydrogen 
to hydroxyl accompanying sulphonation, water being then 
eliminated from the hydroxysulphonic acid ; it is, probably, 
closely related to the dibromocamphorsulpholadlone, 
CioHi2Br2S04, recently described (Lapworth and Kip- 
ping, Proc, 1896, xii., 77), and it lesembles the latter in 
ordinary properties. It crystallises from chloroform and 
ethylic acetate in lustrous transparent plates or prisms, 
melts at about 290°, and is moderately easily soluble in 
boiling acetic acid, chloroform, and ethylic acetate. It 
is very stable, and separates, unchanged, from a solu- 
tion in nitric acid (sp. gr. i*4), even after heating for 
some time ; it seems not to be attacked by cold potash 
(sp. gr. i'3), and, even on boiling, it is only slowly dis- 
solved. 

Dr. Lapworth has, independently, observed the forma- 
tion of this ladlone from a-bromocamphor and anhydro- 
sulphuric acid. 

172. " Dimethylketohexamethylene." By F. Stanley 
Kipping, Ph.D., D.Sc. 

In a recent paper on camphoric acid {Amer. Chem. 
jfourn., 1896, xviii., 685), Noyes describes the prepara- 
tion, from dihydrocampholytic acid, of a ketone which 
forms an oxime melting at 112 — 113°, and possesses an 
odour similar to that of camphoroxime. On comparing 
the melting point of this oxime with that of the isomeric 
oxime of dimethylketohexamethylene, he found that, for 
the latter, the author had given the melting point 114 — 
115° (Trans,, 1895, 'xvii., 349), whereas Zelinsky had 
given it as 104 — 105° (Ber., 1895, 28, 781). Noyes him» 
self then prepared dimethylketohexamethylene oxime, 
and found the melting point to be 120 — 122". 

The possible identity of the two oximes in question 
being a matter of great importance — for, if their identity 
were established, much light would be thrown on the 
constitution of camphor — the author has prepared 
dimethylketohexamethylene by the improved method 
recently described (Kipping and Edwards, Proc, 1896, 
xii., 188), and has made further experiments with this 
substance. 

The oxime, prepared in the usual manner, is at first 
very oily, apparently from the presence of unchanged 
ketone, but it soon becomes a semi-solid crystalline mass ; 
when freed from oil and re-crystallised once or twice, it 
melts quite sharply at about 114°, but further purification 
raises the melting point to ii7"5° (uncorr.), at which 
point it remains, even after six successive crystallisations 
from different solvents. This melting point and that 
previously recorded were taken with an ordinary standard 
thermometer ; observations made with a short thermo- 
meter, the thread of which was entirely immersed, gave 
a m. p. of Ii8"5 — 119°. Noyes does not state whether 
the m. p. 120 — 122°, is corredled, nor how the observation 
was made, and the range of 2° would seem to indicate 
that the substance did not melt sharply ; he also leaves 
the identity of his dimethylketohexamethylene oxime 
with the oxime of the ketone which he obtained from 
camphor an open question. 

Noyes suggests that the several preparations of the 
oxime obtained respedlively by Zelinsky, by himself, and 
by the author, may be mixtures of stereoisomerides, and 
the latter has therefore directed attention to this possi- 



Cbbmical News, I 
Jan. 22, 1807. I 



Enantiomorphism. 



45 



bility ; there are certainly indications of the presence of 
more than one substance in the crude oxime, as a few 
crystals, melting not sharply at about 75°, have been 
separated ; nevertheless, the only crystalline producft 
which has yet been isolated in any quantity is that which 
melts sharply and constantly at 1185 — 119° (corr). 

This oxime crystallises from a mixture of chloroform 
and light petroleum in lustrous transparent prisms, which 
have been examined by Mr. Pope. " The crystals consist 
of monosymmetric prisms, which show the forms |ioo|) 

{001 1 , -jiiol, and I III I; the plane of symmetry is 
the optic axial plane, and an optic axis emerges normally 
to the face (100). Some faces give good refle(5tions, but 
parallel faces do not give images at 180° to one another, 
a behaviour which is frequently observed in the case of 
mixtures." This indication that the oxime may be a 
mixture, in spite of its constant melting point, must be 
borne in mind, and if confirmed, the different melting 
points of the various preparations would be accounted for. 

In order to facilitate the identification of dimethyl- 
ketohexamethylene, the author has prepared the semi- 
carbazone ; this compound slowly separates in crystals on 
warming the ketone with a solution of semicarbazone 
hydrochloride and sodium acetate in dilute alcohol. 
After re-crystallisation it melts at about 196°, and further 
treatment does not seem to change its melting point. A 
sample dried at 100° gave = 59-26, H = g'36 percent; 
calculated for C9H17N3O, C = 59'o2, H = 9-29 per cent. 

Dimethylketohexamethylene semicarbazone is fairly 
soluble in cold chloroform, but less so in cold benzene and 
ethylic acetate, and crystallises best from methyl alcohol 
in the form of small translucent well-defined prisms. 
Heated slowly from about 175°, and using a short thermo- 
meter, it begins to sinter at about 190°, and melts com- 
pletely at about 200 — 201°, effervescing, but not darkening; 
the m. p. depends on the size of the crystals and on the 
rate of heating. The crude semicarbazone seemed to be 
homogeneous, and the yield appeared to be good, but as, 
on re-crystallising the preparation from boiling acetic 
acid, most of it suffered decomposition, further experi- 
ments are necessary to prove that only one semicarba- 
zone exists. 

173. •' The Localisation of Deliquescence in Chloral 
Hydrate Crystals." By William Jackson Pope. 

Chloral hydrate crystallises from solution in large 
monosymmetric plates, showing the forms lioo}-, |oii|> 
and |iiiK and having the axial ratios — 

a:b: £ = 1-6369 : i : 1-3951, 18 = 59° 5' ; 
these crystals consists of the same modification of chloral 
hydrate as was obtained in previous experiments (Pope, 
Proc, 1896, xii., 142), and described as the biaxial 
modification, stable at ordinary temperatures. The 
crystals deliquesce in the air, but in a peculiar manner ; 
the forms \oii\ and |iii} rapidly absorb water 
vapour, and after a few minutes exposure become covered 
with a layer of solution, whilst the faces of the form 
■|ioo| remain perfedly bright during a considerable 
time. The attraftion for moisture exercised by the 
pinacoid \ 100 \ is thus much less than that exhibited by 
the other two forms. 

It is consequently concluded that crystal deliquescence, 
like crystal solubility and other properties, varies with the 
direction in the crystal perpendicular to which its 
intensity is measured. 

174. •' Enantiomorphism.** By William Jackson 
Pope and Frederic Stanley Kipping. 

Crystals of the two enantiomorphous forms of a sub- 
stance which exhibits circular polarisation only in the 
crystalline state, and in which the circular polarisation 
is an inherent property of the crystal struAure, i.e., of a 
substance belonging to Class 26 (Pope, Trans., 1896, 



Ixix., 971), should be deposited from the optically inadlive 
solution in equal numbers, unless any disturbing fadtor is 
operative favouring the deposition of crystals of one 
particular enantiomorphous form, as, for example, contadt 
of the slightly supersaturated solution with a crystal of 
that form. The truth of this statement can be demon- 
strated from our present knowledge of crystal siruAure, 
and is also evident from a consideration of the recent 
work of Landolt {Ber., 1896, xxix., 2404), who showed 
that the crystalline powder of sodium chlorate, which 
rapidly separates from aqueous solution, consists of 
almost equal quantities of dextro- and laevo-rotatory 
crystals. The authors have extended these observations, 
and by taking a number of different crops of the large 
crystals deposited by spontaneous evaporation of sodium 
chlorate solution, have ascertained that the average 
numbers of dextro- and lasvo-crystals deposited are the 
same, in absence of any disturbing fadlor. 

It seemed probable that if a substance which is optically 
adive in solution is introduced into an aqueous solution 
of sodium chlorate, the presence of the former would 
favour the deposition of chlorate crystals of one particular 
enantiomorph, and experiments were consequently made 
to test this view. About 5 per cent of some substance, 
such as dextrose, mannitol, and isodulcitol, was dissolved 
in a saturated sodium chlorate solution, and the crystals 
of the salt deposited on spontaneous evaporation exam- 
ined; a great preponderance of laevo- crystals separated 
from the dextrose solutions whilst m the separation from 
the isodulcitol solutions the dextro-crystals were in 
excess. The mannitol solutions deposited rather more 
laevo than dextro-crystals ; a number of crops from each 
solution were colledled, and similar behaviour was noticed 
with each crop. 

This seledlive deposition would seem to indicate, as 
would, indeed, be expedted, from a consideration of the 
equilibria possible in such systems, that the solubility of 
a dextro-enantiomorph of Class 26 (see above) in a liquid 
containing an optically adive substance, differs from the 
solubility of the Isevo-enantiomorph in the same solvent. 
Solubility determinations, and also determinations of the 
rates of growth of dextro- and laevo-crystals of sodiuiti 
chlorate in optically adlive solutions are in progress. 

There would seem to be no d priori reason why a sub- 
stance optically adive in solution only and possessing a 
high specffic rotation, should exert more directive 
influence on the deposition of crystals of Class 2b than 
an optically adive substance of very low specific rotation, 
the only condition necessarily favouring the deposition of 
crystals of a particular enantiomorph being that there 
should be an asymmetric compound in solution. Using 
methods such as those indicated above, it might, there- 
fore, be possible to determine with ease and rapidity 
whether certain substances which, although containing 
asymmetric carbon atoms, are optically inadlive in solu- 
tion, are really asymmetric compounds, the inadtivity in 
solution being due to a compensation brought about 
amongst the four different groups attaehed to one asym- 
metric atom. Experiments respediing this point are in 
progress. 

Several cases, such as that of camphorsulphonic 
chloride (Kipping and Pope, Trans., 1893, Ixiii., 560), are 
known in which equal quantities of optical antipodes, 
when crystallised together, apparently do not form a 
racemic compound. In the light of the foregoing results 
it should be possible to effed a partial separation of such 
mixtures, and even of racemic compounds, by crystallising 
them from a solution containing an optically adlive sub- 
stance. Experiments on the separation of a number of 
racemic compounds, and of inadlive mixtures of 
optical antipodes by methods based on the above con- 
siderations, have been commenced, but the results are 
not yet sufficiently conclusive to warrant any definite 
statements respedting them. 

Premising the truth of the considerations stated above, 
Eakle's observation {Zeit,/, Kryst., 1896, xxvi., 562} that 



46 



Inorganic Chemical Preparations, 



I Chemical News, 
( Jan. 22, 1807. 



a sodium periodate solution containing sodium nitrate 
deposits more lasvo- than dextro-crystals of the periodate, 
is quite incomprehensible. 

Important Notice to Authors of Papers. 

The attention of authors is diredled to the following 
resolution of the Council. 

•• No title shall be included in the list of titles of papers 
to be brought before a Meeting of the Society, unless the 
paper and an abstradt of it are in the hands of the Secre- 
taries at least three days before the date of the Meeting ; 
and no announcement of titles can be made in the Pro- 
ceedings until the papers have been received by the 
Secretaries." 



NOTICES OF BOOKS. 



Register of the Associates and Old Students of the Royal 
College of Chemistry, the Royal School of Mines, and 
the Royal College of Science, with Historical Iniro- 
duAion and Biographical Notices and Portraits ot Past 
and Present Professors. By Theodore G. Chambers, 
Assoc. R.S.M. London : Hazell, Watson, and Viney, 
Limited, 1896. 8vo., pp. 230. 

The "Department," as it is often styled in brief, is not 
by any means sufficiently known either to its admirers or 
to its critics. Its origin, its development, its past his- 
tory, and its future prospedts are all debatable subjedls. 

The first step towards the formation of the establish- 
ment in question was taken in 1832 by Sir Henry de la 
Beche. He suggested that a collection should be formed 
and placed under the charge of the Office of Works. The 
institution thus founded was named the Museum of 
Economic Geology, and was to contain specimens of 
various mineral substances used for roads or construct- 
ing public works or buildings, employed for useful pur- 
poses or from which useful metals are extradted. 

The building first occupied was No. 6, Craig's Court, 
and Richard Phillips, F.R.S., an eminent analyst, was 
appointed curator. In the laboratory of the Institution 
samples of ores, soils, and general minerals were analysed 
at a fixed moderate charge. The establishment was 
transferred from Craig's Court to Jermyn Street in 1849, 
and during the following years boxes and hampers which 
had been lying for years at Craig's Court were opened 
and their contents classified and arranged. In 1851 the 
formal opening of the museum took place under the 
chairmanship of Prince Albert. In 1854 Huxley was 
appointed Professor of Natural History, vice E. Forbes, 
who had accepted the Chair of Natural History at the 
University of Edinburgh. Robert Hunt resigned the 
ledtureship on physical science, and Professor Sir G. G. 
Stokes was appointed in his stead. It must be men- 
tioned that Prof. Forbes, F.R.S., in an introductory 
ledlure on the " Educational Uses of Museums," com- 
mented rather sarcastically on the apathy evinced by the 
public. 

With the inauguration of the " Department " a change 
ensued. Whereas the Diredtor-General of the Geological 
Survey and Diredor of the School of Mines had hitherto 
reported diredl to a Minister of State, he had now to con- 
dua his communications through Mr. Henry Cole, who, 
in 1854, was constituted Inspedtor. General of Schools 
and Museums, his title being afterwards changed to 
Secretary of the Department of Science and Art and 
Diredtor of the South Kensington Museum. 

Lyon Playfair resigned his appointment in 1858, and 
Captain F. Donnelly virtually obtained the executive con- 
trol of the Department of Science and Art, a striking 
feature being the preponderating military charadter of the 
" Department." It is sarcastically said abroad that 
Britain puts her army and navy under the chief control 



of civilians, and by way of compensation hands over the 
guidance of scientific education to soldiers. 



Inorganic Chemical Preparations, By Frank Hall 
Thorp, Ph.D., Instructor in Industrial Chemistry in 
the Massachusetts Institute of Technology. Boston 
(U.S.A.) and London : Ginn and Co. 1896. Pp. 238. 
This excellent work consists of two main sedlions; — An 
introdudlory or general portion, and a second or experi- 
mental part. The former contains general experimental 
diredlions, and is very judiciously drawn up. We find a 
simple precaution against the tiresome phenomenon 
known as " creeping." Dr. Thorp recommends the edges 
of the beaker and the evaporating dish to be smeared with 
a very thin layer of paraffin oil or vaseline. 

On hydrometers the author speaks very sensibly and 
emphatically. For liquids heavier than water he pro- 
nounces Baume's hydrometer an utterly unscientific 
instrument, whose readings bear no very diredl relation to 
true specific gravity. An investigation made a few years 
ago reveals some thirty-four different scales none of 
which were corredt; yet, in spite of its demonstrably 
fallacious character, it prevails largely in America and on 
the European Continent among people who are loud in 
their condemnation of Britain for her tardiness in adopting 
the decimal system of weights and measures. With us 
it is comparatively little used for liquids heavier than 
water. 

An appendix shows the approximate atomic weights 
and valencies of the elements. 



A Short Catechism of Chemistry arranged for Beginners, 

being an Introduction to the Study of the Science by 

means of Question and Answer. By Alfred J. 

Wilcox. London: Simpkin, Marshall, Hamilton, 

Kent, and Co. (Ltd.). Middlesbrough: T. Woolston. 

Entered at Stationers' Hall. Pp. 16. 

If there is still room for another elementary work on 

chemistry, we may still ask whether the form of question 

and answer possesses any decided recommendations ? 

The complaint is generally made that the pupil learns 

without understanding. 

In the remarks on the word " Elements " we are told 
that four of them are gases, — oxygen, hydrogen, nitrogen, 
and chlorine. Now if the author does not recognise the 
elementary charadter of argon and helium, he must surely 
class fiuorine among the gases. It is to be noted that the 
author, in his Preface, tells us that "his practice of fre- 
quently revising with his class the elements of the Science 
has — and especially before an examination — invariably 
given excellent results." This we do not in the least 
dispute; the catechetical system is likely to enable the 
pupil to answer questions whether he knows or not. 



Catalogue of Books by Meyer and Miiller, 51, Markgrafen- 
Strasse, Berlin, W. (" Wegweiserdurch die Litterature 
der Chemischen Technologie "). 
A publishers' trade catalogue, containing not a few 
curious works, such as " Margarita Philosophica " (1583), 
by G. Reisch, "Pandora," the stone of the Muse, by 
means of which the old philosophi and also Theophrast 
Paracelsus ennobled the imperfeCt metals by the power 
of fire (1588) ; Helmont (Opera omnia, 1648) ; Guaita, 
St. de, " Essais de Sciences Maudites." II. Le Serpent 
de la Genese. I. " Le Temple de Satan": this book is 
of as recent a date as 1891 ! 



El Kamlic de Komposizion ke esperimenta el Aqua de 

"■ El Salto " durante el Imbierno. By K. Newman. 

Santiago de Chile. 1896. 

The author's conclusions are: — The water of El Salto 

undergoes during the winter a chemical and bacteriological 



Jbbmical Nbws, I 
Jan. 22. 1897. I 



Chemical Notices Jrom Foreign Sources, 



alteration, which causes it to lose its quality and pota- 
bility. In June and July there existed in the water of 
£1 Salto a micro-organism with all the charaders of 
B, Colt communis. 



CORRESPONDENCE. 



47 



I THE CYANIDE PROCESS FOR GOLD 
EXTRACTION. 

To the Editor of the Chemical News. 
Sir, — Kindly publish for me, as an old subscriber to 
the Chemical News, the singular and unexpe(5led faft 
that aqueous solutions of cyanogen do not exert the least 
solvent adion on gold or silver. Of course as the gas 
decomposes there is a slight solvent adlion, but even this 
is far too slow and destrudtive of the gas to make ex- 
traftion of gold a commercial success. This must prove 
to be interesting to cyanide men. 

I found this fa(5t while engaged as an expert in the case 
Government re McDollin and Co., and published it here 
September 17th last, in a paper to our Pnilosophical 
Society. — I am, &c., 

William Skey, 
Analyst to the Home Department, N.Z, 

The Mines Department, Wellington, N.Z., 
December 5. i8g6. 



CHEMICAL 



NOTICES FROM 
SOURCES. 



FOREIGN 



Note.— All degrees of temperature are Centigrade unless otherwise 

expressed. 

Comptes Rendus Hebdomadaires des Seances, deVAcademte 
dcs Sciences. Vol. cxxiv., No. i, January 4, 1897. 
Position of the Academy of Sciences. — The fol- 
lowing changes have talcen place in the membership of 
the French Academy of Sciences : — Deaths since January 
1st, 1896 : Resol, Tisserand, Fizeau, Daubree, Trecul, 
Reiset, Sappey. There have been eledled : Bertrand, 
Michel Levy (in the Sedlion of Mineralogy) ; Muntz 
(Sedtion of Rural Economy). Among the free Academi- 
cians, i.e., those not attached to any especial sedlion, 
Ronche. The following members have still to be re- 
placed : Resol (Sedlion of Mechanics), Tisserand (Astro- 
nomy), Fizeau (General Pnysics), Trecul (Botany), 
Sappey (Anatomy and Zoology), and Tchenichef (Foreign 
Associate). The following correspondents are deceased : 
Gylden and Gould (Astronomy), Prestwich (Mineralogy), 
Kekule (Chemistry), Baron von Miiller (Botany), Marquis 
de Menabree (Rural Economy). The correspondents 
eledled (Sedlion of Astronomy) are : Gill, vice Cayley, 
deceased; Van de Sande Bakhuyzen, vice Newcomb, 
eledled Foreign Associate; Cnristie, z»tc« Hind, deceased. 
The following correspondents have still to be replaced : 
Gylden and Gould, deceased (Astronomy) ; Kekule, de- 
ceased (Chemistry) ; Prestwich, deceased (Mmeralogy) ; 
Baron Miiller, deceased (Rural Economy) ; Marquis de 
Menabrea, deceased (Rural Economy) ; Loven, deceased 
(Anatomy and Zoology). 

Effedls of the Combined Variation of the Two 
Fadlors of the Expenditure of Muscular Energy on 
the Value of the Respiratory Exchanges. — A, Chau- 
veau, with the assistance of J. Tissot. — This paper is too 
little and too doubtfully chemical in its charadler to merit 
insertion or abstradlion in the Chemical News. 

Adlion exerted upon the Alkaline Haloid Salts by 
the Bases wnich they contain. — A. Ditte. — The alka- 
line bases exert upon the alkaline haloid salts a precipi- 
tating adlion analogous to that produced by the 
corresponding acids. 



Adlion of Ammonia upon Tellurium Bichloride.— 
Rene Metzner.— Ammonia ads upon tellurium bicnloride 
in a manner which differs according to the temperature 
applied. At 200° to 250° the readlion, which is very 
slow, is represented by — 

3TeCi4 -f 16NH3 = 3Te -f i2NH4Cl-f-4N. 
At 0° the ammonia combines with tellurium chloride. At 
a lower temperature we may obtain combination of tellu- 
rium and nitrogen. When the operation succeeds the 
apparatus contains, after the washing is completed, a 
substance of a fine lemon-yellow colour, of the compo- 
sition TeN. This nitride is friable and amorphous. It 
detonates with extreme violence if struck, producing a 
black vapour of tellurium in an impalpable powder. Tellu- 
rium nitride is not attacked either by water or dilute 
nitric acid. In contadl with potassia it gives off all its 
nitrogen in the state of ammonia. 

The Absorption of Hydrogen Sulphide by Liquid 
Sulphur.— H. Belabon. — Liquid sulphur maintained at 
a temperature above 170°, in presence of sulphuretted 
hydrogen gas, absorbs a notable quantity of this gas. 
The quantity of gas absorbed is so much the greater as 
the temperature is higher, the pressure remaining the 
same. In all cases the gas escapes at the moment of the 
solidification of the sulphur ; the gaseous liberation is a 
consequence of solidification. Pure hydrogen is not ab- 
sorbed by liquid sulphur. 

Produdlion of Vanilline by means of Vanillo. 
Carbonic Acid.— Ch. Gassmann.— The author boils i part 
of this acid with 2 parts of aniline until the escape of 
carbonic acid has ceased. There is formed a substituted 
benzylidene-aniline, which is separated from excess of 
aniline by means of a current of steam. The vanilline- 
aniline is finally split up by a brief ebullition with dilute 
sulphuric acid at 50 per cent. The vanilline formed is 
isolated by extradion with ether, from which it easily 
crystallises. 

The Transformation of Eugenol into Isoeugenol. 
— Ch. Gessmann.— Not adapted for useful abstradlion. 

A New Method for Determining Sulphur in Iron. 
— W. Schulte.— In order to evade the disadvantages of 
the bromine method and of working with barium sulphate 
the author dissolves the iron in dilute hydrochloric acid, 
condudls the gases evolved through a solution of cadmium 
acetate acidulated with acetic acid, and transforms the 
resulting cadmium sulphide in order to bring it into a 
state capable of easy determination into copper sulphide 
by the addition of an acid solution of copper sulphate. 
The copper sulphide is ignited and weighed as copper 
oxide. One atom of sulphur yields exadlly i mol. of 
copper oxide; 31-98 8=79-14 CuO. It is not admissible 
to pass the gases evolved into the copper solution, since 
phosphorus and arsenic occasion separations. We pre- 
pare in the first place three solutions. I. 25 grms. cad- 
mium acetate (or 5 grms, cadmium acetate -f- 20 grms. 
zinc acetate) and 200 c.c. glacial acetic acid per litre; 
II. dilute hydrochloric acid (i-f-2) ; III. 80 grms. copper 
sulphate and 175 c.c, concentrated sulphuric acid per 
litre. The apparatus consists of a boiling flask, into 
which are introduced 10 grms. comminuted iron, a funnel 
tube with a cock for the introdudlion of 200 c.c. hydro- 
chloric acid, a bent glass tube as a reflux refrigerator, and 
a receiver with an appendix and a second safety receiver. 
Into the receiver there are introduced 40 to 50 c.c. of the 
cadmium solution. The development of gases is effedled 
in the cold, heat is then applied with a Bunsen burner so 
as to complete the solution of 10 grms. iron in ninety 
minutes. Tne cadmium compound in the receiver is then 
transformed with 6—7 c.c. of the copper solution, the 
copper sulphide is then filtered off and ignited. If it is 
intended in this manner to determine zinc and manganese 
sulphides in iron sulphide, the portion operated upon 
must not exceed 0-15 grm. For 10 grms. iron the entire 
process requires two-and-a-half hours,— S<«A/ md, Gisen 



48 



Meetings for the Week. 



(Chemical Nbws 
( Jan. 22, 1897. 



MISCELLANEOUS. 

Mica. — Messrs. Wiggins and Sons, Mica Merchants, 
have, after rebuilding, returned to their old address, 102 
and 103, Minories, both of which buildings are entirely 
devoted to their business. 

Royal Institution. — On Saturday, Jan. 23, Mr. Carl 
Armbruster will deliver the first of three lec5lures on 
•' Negledted Italian and French Composers " (with nume- 
rous vocal illustrations). The Friday Evening Meetings 
of the members will commence on Jan. 22, when Prof. 
Dewar will deliver a ledure on " Properties of Liquid 
Oxygen." Prof. J. C. Bose, Professor of Presidency 
College, Calcutta, will deliver his discourse on " The 
Polarisation of the Eledric Ray " on Friday evening, 
Jan, 29th, and not on Feb. 5th as previously announced. 
The discourse on this night will be delivered by the Bishop 
of London, who will take as his subjed " The Picturesque 
in History." 

Sensitive Litmus>Paper. — Ronde. — The strong alka- 
line cubes occurring in commerce are covered with twelve 
to fifteen times their quantity of water, and allowed to 
stand for one day. The deep blue mixture is then treated 
with sulphuric acid until it becomes a light red, and 
heated on a steam-bath for fifteen minutes. To the 
liquid, which generally turns blue again, dilute sulphuric 
acid is added until the filter-paper becomes of a reddish- 
violet on immersion. When cold it is strained through a 
cloth, and the liquid is so adjusted, by the addition of 
drops of dilute sulphuric acid or traces of powdered 
litmus, that pieces of filter-paper, if immersed and 
quickly dried, take the desired red or blue tint. This 
method readily yields papers of a sensitiveness i = 150,000. 
—Pharm. Zeitung and Chem. Zeitting. 

Royal Academy of Sciences of Turin. — From a 
courteous communication from the Academy we learn 
that from January ist, 1897, to the end of December, 
1898, this prize will be awarded to any scientific author or 
inventor, of whatever nationality, who, during the years 
1895 — 98, shall, in the judgment of the Royal Academy 
of Sciences of Turin, have made the most important dis- 
covery or published the most valuable work on physical 
and experimental science. The prize (deducing income- 
tax !) will be 9600 francs. Candidates must send in this 
work {in print) to the President of the Academy within 
the stated time. MSS. will be disregarded. Unsuccess- 
ful work will not be returned. — Signed, G. Corb (Presi- 
dent) ; E. D. Ondic (Secretary of the Commission) ; 
Turin, January ist, 1897. 



MEETINGS FOR THE WEEK. 

MoNDAV, 25th.— Society of Arts, 8. (Cantor Leftures). "Material 

and Design in Pottery," by Wm. Burton, F.C.S. 

Tuesday, 26th.— Royal Institution, 3. " Animal Eleftricity," by 

Prof. A. D. Waller, F.R.S. 

— . Society of Arts, 8. " The Artistic Treatment of 

Heraldry," by W. H. Si. John Hope, M.A. 

Wednesday, 27th.— Society of Arts, 8. " Voice Produftion," by 

William Nicholl. 
Thursday, 28th.— Royal Institution, 3- " Some Secrets of Crystals," 
by Prof. H. A. Miers, F.R.S. 
— Society of Arts, 4.30 (at the Imperial Institute). 

"The Moral Advancelof the Peoples of India 
during the Reign of Queen Victoria," by 
William Lee-Warner, M.A., C.S.I. 
-^ Society of Arts, 8. *' The Mechanical Produ<5tIon 

of Cold," by Prof. James A. Ewing, M.A., F.R.S. 
Friday, 29th.— Royal Institution, 9. " The Polarisation of the 
Eleftric Ray," by Professor Jagadis Chunder 
Bose, M.A.. D.Sc. 
Saturday, 30th.— Royal Institution, 9. " Negledled Italian and 
French Composers," by Carl Armbruster. 



FOR SALE. — The Chemical Gazette, 
Complete Set (unbound and uncut), 17 volumes ; from Novem- 
ber, 1842, to December, 1859.— Address, "Publisher," Chemical 
News Office, Boy Court, Ludgate Hill, London, E.C. 



Analytical Chemist (26) desires Post in 

•^^ Laboratory or Work. Assistant for over two years to leading 
London Chemist, to whom reference may bs made. — Address, 
' Assistant," Chbmical News Office, Boy Court, Ludgate Hillf 
London, E.C. 

Chemical Student, who has been a pupil for 
the last year and a half in well-known Agricultural Labora- 
tory, and previously at the Royal College of Science, seeks employ- 
ment. — Address, S., 29, Park Hill, Clapham. 

pOR SALE.—" Journal of the Chemical 

■^ Society," 1877 to 1896, unbound, cut, in good condition ; also 
about ICO Chemical, &c., books. Particulars supplied.— Willis, 18, 
Dagmar Road, Camberwell. 

\X/'anted, a Pupil-Assistant in a London 

' * Laboratory. Applicants must have a good knowledge of 
General and Analytical Chemistry. Small salary. — Apply, " X. V.," 
Chemicai. News Office, Boy Court, Ludgate Hill, London, E.C. 

WALL- PAPER STAINER wants Direaions 

^ ^ how to mix Colours and other Chemicals for the manufac* 
fafture of SANITARY WALL-PAPERS. Will be paid after suc- 
cessful experiment. Best machinery already provided. — Communi- 
cate with Moeller and Condrup, 78, Fore Street, London, E.C. 

T IVERPOOL COLLEGE of CHEMISTRY, 

J— ' Duke Street.— TO BE LET, ist February, 1897. Established 
in 1S48 by the late Dr. Sheridan Muspratt — Apply to Walton 
Batcheloor, ij, Stanley Street, Liverpool. 

RED-WOOD LAKES 

Free from Aniline, 

as Crimson Lake, Cochineal Red, Purple Lake, &c., 

Supplied as a SPECIALITY by 

Dr. BODENSTEIN and KAESTNER, 

Red-Colour Manufa(5lurers, 

(Established 1840), 

SAALFELD-ON-SAALE, GERMANY. 



Mr. J. G. LORRAIN, M.I.E.E., M.I.M.E, M.S.C.I., 

Fellow of the Chartered Institute of Patent Agents, 
Norfolk House, Norfolk Street, London, W.C. 

" PATENTEE'S HANDBOOK " Post Feee on application. 



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these Furnaces. Original letters may be seen at the Works and the 
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NELSON & SONS, Shirland Works, 
Twickenham, London, S.W. 

THE CHEMICAL NEWS 

AND 

JOURNAL OF PHYSICAL SCIBNCE. 
iidited by WILLIAM CROOKES, F.R.S. 

Published every Friday. Price 4d' Annual Subscription poit free 
including Indices ,£1. 

CHARGES FOR ADVERTISEMENTS. 

£ i. d. 
Five lines lu column (about 10 words to line) o 3 6 

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A reauciton made ior a series of tnsertiom. 

Cheques and Post-Office Orders, crossed "London and Coanty 
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BOY COURT. LUDGATE HILL, LONDON, E.C. 



Chbuical Nbws, \ 
Jan. 29, 1897. t 



Unity 0/ the Atomic Weights^ 



49 



THE CHEMICAL NEWS 

Vol. LXXV., No. 1940. 



THE UNITY OF THE ATOMIC WEIGHTS. 

By KARL SEUBERT. 

In a Report by F, W. Kiister, on the Progress of Physical 
Chemistry in the year 1895, which lately appeared in the 
Zeit. Anorg. Chem., it is mentioned that " all the more 
recent determinations of the atomic weight of hydrogen 
show in accordance that the relation : H lies between 
16 : i'007 and 16 : 1*008 (or, in the old style, H : O between 
I : I5'87 and i : I5"88)." We read further that this result, 
which is not novel, will scarcely prevent the value 
H : O = I : i5'96 from being still quietly employed. I cannot 
share the apprehension of my colleague, Kiister. I have at 
once, after Morley's great work had become known to me 
in its details, recognised the inadmissibility of the value 
I5*96, and have expressed this convidtion on the next 
opportunity. The remaining adherents of the " old 
style " may probably think with me, since what formerly 
led us to the assumption of the value O = i5-i6 is no 
longer valid, this number no longer presenting the result 
of the most trustworthy experimental determinations of 
the atomic weight of oxygen in reference to the atomic 
weight of hydrogen taken as unity. This result has 
seemed for some time probable, but the question was too 
much contested to admit of a full decision, and a certain 
reserve appeared to me the more imperative as now and 
then determinations spoke in favour of the older values 
15-96 and 16. At present we may, however, admit that 
Morley's relation, O : H = i5;879: i, approaches so closely 
to the truth that it will not in future undergo any modifi- 
cation of importance. The uncertainty, in all probability, 
amounts to not more than a unit in the second decimal 
place, or about 0'o6 per cent of entire value. Hence the 
atomic weight of oxygen now ranks among those most 
accurately determined, and its possible error becomes 
perceptible only in the higher values of atomic weights, 
and even there in decimal places which in any case must 
be held doubtful. 

There is near at hand an expedient to avoid the un- 
pleasantness involved in the uncertainty and the change 
in the atomic weight of oxygen by fixing this value arbi- 
trarily, and thus rendering it independent of the issue of 
stochiometrical determinations. This expedient must, 
however, be used with the utmost possible limitation. I 
should not delay for a moment to vote to-day for = i6, 
if the result of the most recent investigations on the 
atomic weight of oxygen evinced considerable deviations 
and uncertainties which rendered a seledion among the 
different values impossible ; but, on the contrary, these 
researches, almost without exception, lead to a value 
derived from an experimental investigation condudled on 
a large scale and in an unexceptional manner, and invest 
it with a degree of probability which attaches to our best 
determinations of atomic weights. If, therefore, a number 
must be established for the atomic weight of oxgen, that 
value has the first claim which— according to our present 
experience — gives our atomic weights a rational unity, the 
atomic weight of hydrogen. 

An advantage which has been put forward in favour of 
the assumption O = 16 is, that then a number of atomic 
weights can be reproduced with sufficient accuracy by 
whole numbers ; but this plea is not sufficient to turn the 
scale in its favour. The new atomic weights are certainly 
less convenient in this respedl. 

They show that Front's hypothesis, both in its original 
form and in the modification proposed by Dumas, is not 
refuted by experiment. The atomic weights of the ele- 



' ments — if we disregard desultory exceptions — are neither 

multiples of the atomic weights of hydrogen nor of 0*5 
nor 0-25, therewith the conclusions attached to this sup- 
posed regularity become baseless. 

0=16. H=i. 

Aluminium .. .. Al 27*11 26-go 

Antimony .. ,. Sb HQ'Q iigo 

Arsenic As 75-1 74*5 

Barium Ba I37*43 I36'40 

Beryllium .. .. Be g'05 SgS 

Bismuth Bi 208 *g 207*3 

Boron B 10*94 10*85 

Bromine Br 79*96 79'35 

Cadmium .... Cd ii2*o iii'i 

Carbon C 12*00 ll'gi 

Calcium Ca 40*01 3g7i 

Caesium Cs I33'0 132*0 

Cerium Ce 140*3 I3g"2 

Chlorine CI 35*46 35'i9 

Chromium .. ,. Cr 52*14 5i'74 

Cobalt Co 59*6 59*1 

Copper Cu 63*60 63*12 

Didymium .. .. Di 142*5 141*4 

Erbium E 166*4 165*1 

Fluorine F 19*10 18*96 

Gallium .. .. ,, Ga 70*1 69*6 

Germanium .. ., Ge 72*5 719 

Gold Au 197*2 195*7 

Hydrogen .... H 1*008 I'oo 

Indium In 114*0 113*1 

Iridium Ir 193*0 191*5 

Iron Fe 56*02 55'6o 

Iodine I 12686 125*90 

Lanthanum ., .. La I38'3 i37'3 

Lead Pb 20691 205*35 

Lithium Li 7*03 697 

Magnesium .. ., Mg 24*26 24*18 

Manganese .. ., Mn 54 94 54*52 

Mercury Hg 200*3 198*8 

Molybdenum.. ,. Mo 96*03 95*3i 

Nickel Ni 58*9 58*4 

Niobium Nb 93*9 93*2 

Nitrogen N 14*04 13 94 

Osmium Os 190*8 189*3 

Oxygen O i6*oo 15*88 

Palladium .. .. Pd 106*3 105*0 

Phosphorus .... P 31*03 30*80 

Platinum Pt 194*8 I93'3 

Potassium .... K 3912 38*83 

Rhodium Rh 103*0 102*2 

Rubidium .. .. Rb 85*4 84*8 

Ruthenium ., ., Ru 101*7 100*9 

Scandium .. .. Sc 44*05 43*75 

Selenium Se 7g'07 78*47 

Silver Ag I07*g2 107*11 

Silicon Si 28*38 28*16 

Sodium Na 23*05 22*88 

Strontium .. .. Sr 87*62 86*96 

Sulphur S 32*06 31*82 

Tantalum .. ., Ta 182*5 i8ii 

Tellurium .. .. Te 127*5 126-6 

Thallium Tl 204*2 202*7 

Thorium Th 232*5 230*7 

Tin Sn 119*10 118*20 

Titanium Ti 48*1 47*8 

Tungsten .... W 184*1 182*7 

Uranium U 23g*4 237*6 

Vanadium .... V 51*2 50*8 

Ytterbium .. .. Yb 173*0 171*7 

Yttrium Y 88*g 88*3 

Zinc Za 65*41 64*91 

Zirconium .. .. Zr 90-6 89*g 

If Kiister further remarks that •* the selection of hydro- 
gen as the unit of the atomic weights has been often 
branded as illogical, and practically not to be upheld," I 



50 



Toxicological Behaviour of Picric A cid. 



(Chbmical News, 
\ Ian. 29, 1897. 



cannot share his opinion. It seems to me most natural 
and logical to refer the atomic weights to the smallest of 
all — that of hydrogen — as the unit. If this is not feasible 
from prai^ical reasons, another unit must be seleded 
out of the series of the atomic weights, as it has been 
done in the case of specific gravities. The unquestionably 
inconvenient numbers which result on referring to 
O = I have led to the expedient of taking the atomic 
weight of oxygen = 1600, and thus creating a unit iden- 
tical with no known atomic weight, though it approximates 
to that of hydrogen. Per se, this choice is illogical, and 
the number 16 only obtains meaning with reference to 
hydrogen. It represents makeshift, founded on the idea 
that the reference to hydrogen as unit would be in prin- 
ciple more accurate. Practically we have obtained such 
a relation by assuming O = i5'879, for which we may more 
briefly substitute I5'88, for in all probability future re- 
searches will modify this value so little that the influence 
of such a correction will be felt in most atomic weights 
only in places which are already uncertain. It is very 
questionable whether the advantages held out for the 
calculation = i6'oo will counterbalance the advantage 
of a really rational, logical unit. — Zeit. Anorg. Chem. 



NOTE ON THE DETERMINATION OF 

EQUIVALENT OF SODIUM. 

By WM. FRENCH. 

For the determination of the equivalent of sodium by 
junior students I have adopted the following method, 
which I find has many advantages over the sodium 
amalgam method mentioned in most pradtical text-books. 




accompanying sketch will explain the experimental part 
of the process. The tube b is completely filled by the 
stoppered burette, A, with dilute alcohol (of such strength 
that sodium dissolves in it at a gentle rate). A piece of 
sodium is quickly weighed and placed in the small dry 
flask, c, which is fitted on to the cork connedled to a 
water syphon aspirator in the usual way. Dilute alcohol 
is then run on to the sodium from the burette, and the 
volume of water displaced after due cooling and levelling 
in the measuring cylinder, d, minus the volume of alcohol 
run in from the burette, gives the volume of hydrogen 
evolved, from which the equivalent of sodium can be 
calculated. 
Grammar School, Bury. 



I have not seen a notice of this modification in any of 
the numerous works on praAical chemistry, and assume, 
therefore, that it is certainly not generally adopted. The 



THE TOXICOLOGIGAL BEHAVIOUR OF 

PICRIC ACID AND ITS SALTS, AND OF 

CERTAIN KINDRED SUBSTANCES. 

By Dr. TH. BOKORNY. 

Free picric acid is a powerful poison for algae ; in a 
0*5 per cent solution they dried within fifteen minutes ; in 
0*1 and o'05 per cent solutions within twenty-four hours. 
Many fungi are not quite so sensitive to picric acid. 

Free picric acid is no powerful poison for fungi. With 
algae a concentration of 0*05 per cent is sufficient for 
poisoning, whilst fungi require one of o*i per cent. 
Ammonium picrate is for low organisms a more powerful 
poison than potassium picrate. 

In a solution of orthobenzoic acid of 0*2 to o'l and 0*65 
per cent all life of algae and low animals was extinguished 
in five hours. 

Potassium nitrobenzoate in a 02 per cent solution 
destroys all animal and vegetable life within six hours. 

According to Weyl, Martins yellow or dinitro-a-naphthol 
is a strong poison for dogs, the fatal dose being 03 grm. 
per kilo, living weight. Naphthol yellow S, a sulpho-acid 
of dinitro-a-naphthol, is harmless. A comparison between 
ortho- and para-nitrophenol shows that the para- com- 
pound is somewhat more poisonous to algae and infusoria 
than the ortho-compound. It would be interesting to 
carry out a comparison between para- and ortho-com- 
pounds in an extensive series of organic compounds. — 
ClumikerZeitung. 



DETERMINATION OF BISMUTH. 
By W. MUTHMANN and F. MAWROW. 

The authors have shown some time ago that hypophos- 
phorous acid is suitable for the determination of copper, 
and especially for its separation from cadmium and zinc. 
Experiments with bismuth have now shown that with suit- 
able precautions it may be completely precipitated as metal 
by the reagent above named. Hence there results a method 
of separation and determination which in many cases 
surpasses in accuracy and expedition the methods hitherto 
known. We shall briefly describe it. 

The solution of the bismuth salt, not too strongly 
acid, is mixed with an excess of hypophosphorous acid, 
and heated on the water-bath until the supernatant liquid 
has become perfedtly clear, and a further addition of the 
reagent heated to ebullition produces no further coloura- 
tion. The metal separates out in the form of a reddish- 
grey spongy mass, which can be easily filtered and 
washed. It is colleded upon a weighed filter or in a 
Gooch crucible, washed with boiling water and then with 
absolute alcohol, and dried at 105°. The original solu- 
tion is best used in a state of moderate concentration, 
and a few c.c. of hypophosphorous acid are forthwith 
added. 



Chbmical Mbws, I 
Jan. 29, 1807. I 



Method of Determining Manganese in Iron Ores, 



Our experiments have been carried out with bismuth 
oxychloride washed up in a little water and dissolved by 
the addition of a few drops of hydrochloric acid. The 
liquid after filtration was tested each time for bismuth by 
the introduction of hydrogen sulphide. There only 
appeared a faint brown colouration if heat had not been 
applied for a sufficient time. In four experiments there 
were used respectively— 

BiOCl. Obtained. Bi per cent. 

o'ii58 grm. o'ogae grm. 79*96 

0*1559 .. 0-1250 „ 80-17 

0-I20I „ 0-0963 „ 8o-i8 

0-1068 „ 00857 ». 80*24 

The average percentage being 8o'i3, and the calculated 
result 8o'i5. 

The method is doubtless applicable for the separation 
of bismuth from metals which are not precipitated from 
their solutions by hypophorous acid, especially from zinc 
and cadmium. — Zeit. Anorg. Chemie, xiii., p. 207. 



51 



SARNSTROM'S METHOD OF DETERMINING 

MANGANESE IN IRON ORES. 

By C. T, MIXER and H. W. DUBOIS. 

About a year ago we had occasion to use a volumetric 
method which would allow the determination of manga- 
nese in iron ores ranging in amounts up to 15 per cent, 
and give results in half-an-hour which would check with 
gravimetric determinations within two-tenths per cent for 
ores as high as 15 per cent, and within a few hundredths 
of a per cent for ores under i per cent. 

We found in use in a neighbouring laboratory a method 
which was generally known as the " Swedish Method." 
This method was found to fulfil the above conditions, 
and seems to have sufficient merit to be more widely 
known. 

The first suggestion upon which the method is based 
was made by Guyard,* although his method of operating 
it did not give very satisfaftory results. 

The first description of the method in its present practi- 
cable form was made by C. G. Sarnstrom, in the Vern- 
kontorets Antialer (Sweden), 1881, p. 401.! 

The principle upon which this method depends is the 
readtioti which takes place when a manganese compound 
higher in oxygen than the manganous state, is dissolved 
in hydrochloric acid, forming a higher chloride, which is 
readily shown by the dark coloured solution. When this 
solution is boiled, it rapidly decolourises, being com- 
pletely converted into manganous chloride, not easily 
oxidised by the air while in the acid solution. 

In neutral or alkaline solutions the manganous com- 
pound has a slight tendency to oxidise in contact with the 
air, but we have never deteded any appreciable oxidation 
under the conditions which we follow. 

The separation of the iron and the manganese is effected 
in such a way that the iron is precipitated as hydroxide, 
and the manganese left in the manganous condition in 
solution. Sodium carbonate is used to precipitate the 
iron as hydroxide, and no trouble is experienced in the 
precipitation of the manganese as a carbonate, provided 
that only a very slight excess is employed beyond that 
necessary to completely precipitate the iron. It is advis- 
able to add the sodium carbonate in the form of a solu- 



♦ Guyard, Chem. News, viii., 292; the following references relate 
to the subsequent modifications of the method ; Habich, Ztschr. Anal 
C/iewt., Ill , 474 i Winkler, Ztschr. Anal. Chem., iii., 423; Morawski 
und Stingl, Jottrn. Pmkt. Chem. (N.F.), xviii., 96: Volhard. Ann 
C/jem. (Liebig), cxcviii ,318. 

t Also published in Berg und Hiittenm., Zeitung, xl , 425. A review 
of the original article appears in the Ztschr. Anal. Chem., xxii., &a. 
We aie indebted to Mr Hugo Carlsson, Chief Chemist ot the Johnson 
Works of Lorain, Ohio, for calling oar attention to Sarnstrom's 
original publication and for furnishing us a translation of the same. 



tion, towards the completion of the precipitation of the 
iron, to avoid such an excess. 

Sarnstrom employs sodium bicarbonate, which has the 
advantage that a greater amount of carbon dioxide is 
generated, preventing subsequent oxidation of the man- 
ganous salt by the oxygen of the air. Manganese bicar- 
bonate is formed, which is readily soluble in the solution 
containing carbon dioxide. 

It is always desirable to test the sodium carbonate or 
bicarbonate for organic matter. 

The results given below show the necessity of avoiding 
an excess of sodium carbonate (the same is true of the 
bicarbonate) in the precipitation of the iron. Aliquot 
portions of a solution of manganese containing 3*i4 per 
cent manganese gravimetrically determined, gave only 
261 per cent when treated with such an excess. Another 
ore giving 869 per cent under the proper conditions of 
this method, when treated with an excess of sodium car- 
bonate gave 5-38 per cent. 

After the precipitation of the irpii in the hot solution, 
the manganese being in the manganous state, is oxidised 
by potassium permanganate, according to the following 
formula : 

3MnO+2KMn04+H20 = 2KOH-t-5MnOa, 
which is the same reaction which takes place in Volhard'a 
method. As the titration takes place direCtly, without 
filtering, the precipitate of ferric hydroxide is an advant- 
age, especially in low manganese ores, as it serves to 
collect the fine precipitate of manganese dioxide and 
causes it to settle more rapidly. 

In ores very low in iron it is desirable to add ferric 
chloride in order to obtain the requisite amount of the 
iron precipitate. 

The Method. — Weigh half a grm. ore into a No. o beaker, 
add 15 c.c. of hydrochloric acid, i-i sp. gr., and boil until 
the residue is clear. If necessary fuse the residue with 
sodium carbonate. Add a few drops of nitric acid to 
oxidise any ferrous iron or organic matter. In magnetic 
ores more of course will be necessary. It is well to test 
for ferrous iron. Evaporate a short time to expel any 
nitrous acid that may have been formed. It is advisable 
to have a good amount of free hydrochloric acid present 
to generate carbon dioxide in the precipitation with sodium 
carbonate. The solution is then washed into a No. 3 
beaker or a flask, which is then filled about two-thirds full 
with boiling distilled water, and solid sodium carbonate 
or bicarbonate added until the iron is completely precipi- 
tated, which is readily indicated by the characteristic 
spongy appearance of the precipitated ferric hydroxide. 
A solution of the salt is preferable for the final precipita- 
tion in order to avoid an excess. 

The solution should be about 80° C. when it is titrated* 
with potassium permanganatedireCtly,withoutfiltering, and 
with intervals of vigorous stirring and settling of the iron 
and manganese precipitates, until the supernatant liquid 
shows a permanent faint pink colour. The first appear- 
ance of the pink colour must not be taken as an indication 
that the oxidation is complete, as gentle heating and 
vigorous stirring will allow more potassium permanganate 
to be added before the permanent pink appears.! 

Multiplying the burette reading by two represents the 
equivalent for one grm., and this multiplied by the per- 
manganate value in manganese, which is the iron value 
multiplied by 02946, gives the percentage of manganese. 

In case of over-titration, it is practicable to titrate back 
with a carefully standardised solution of manganous 
chloride, which is prepared by evaporating 15 c.c. potas- 
sium permanganate down to 3 or 4 c.c, adding a few 
drops of hydrochloric acid and boiling as long as chlorine 
comes off. The solution should be neutralised with 
sodium carbonate, and diluted to lo c.c, when i c.c. is 
equal to i c.c. of potassium permanganate. 

* Which should be done immediately after the neutralisation, in 
order to avoid any opportunity for oxidation. 

t This is a very important point not only in relation to this method, 
but in all methods where potassium permanganate is used. 



52 



Metal Separations by means of Hydrochloric A cid Gas, 



; Chbhical Nbws, 

Jan. 29, 1897. 



(Ford's) 
Per cent. 
5298 



44'3 



Sarnstrom states that the method is reliable for high 
manganese ores and ferro-manganese " where it is not 
necessary to determine the manganese closer than a few 
tenths of i per cent." 

Our experience does not confirm this. The results 
average from i to 2 per cent too low, so that we do not 
consider the method at all reliable for high percentages 
of manganese. 

The following are some results which show this : — 

Gravimetric 
Sarnstrom. 
Per cent. 

Illinois ore *. .. 52-06 (i) 
„ .... 51-91 (2) 

1 51*40 (3) 

„ .... 51-78 (4) 

.. •• •• 51-37 (5) 

5i'37 (6) 

No. 595 42-07 

.. 4235 

42*90 — 

,, 42-60 — 

In analyses from No. i to No. 4 sodium carbonate was 
used for the precipitation. To determine whether the 
employment of sodium bicarbonate would be advantageous, 
No. 6 was so treated, while at the same time No. 5 was 
precipitated with sodium carbonate, yielding the same 
result. We have tried sodium bicarbonate with low man- 
ganese ores, but have never noticed any pradtical advan- 
tages, while theoretically, as we have pointed out above, 
there should be an advantage in the employment of 
sodium bicarbonate. 

This discrepancy with high percentages of manganese 
may possibly be accounted for by the fadt that the large 
precipitate of manganese dioxide may adt in a purely 
mechanical way in protedling the final amounts of the 
manganous chloride from being fully oxidised to dioxide 
by the potassium permanganate. It is to be noted in this 
connexion that Volhard's method does not generally give 
reliable results with such high percentages of manganese. 

The following are some results obtained by this and 
other methods : — 





Samstrom 


. 


Volhard. 


Gravimetric. 


A. Magnetic . 
Specular . 

B. Mixture of 
blue granu- 
lar and red 
hematite 


. 0*07 

0-30 

• 0-32 

0-28 




o-io 
o-o8» 

0-31 
0-29 


0-07 

0*29 
0-30 


C. Limonite . 


. 1-03 




1*02 


I '09 


11 < 
D. Silicious or 


. 1-05 
e 2-98 




1-05 
3*o8 


2*93 


Cary Empire . 

M II 


3*07 
. 3 93 
. 3-88 


3*07 

T. V. Church 

Illinois Steel Co. 


■3 "94 


Dexter No. 2 


6-04 
. ■ 602 




6*02 


6-01 




6-01 




— 


— 


Davis ore.. 
Newark ore . 


. 878 

. i'48 


A. G 

Duques 


8-62 L8 86 
. McKenna, ( (Ford's) 
ne Steel Works 1-50 


No. 57 .. . 
No. 218 .. . 


. 5*39 
. 559 




5*39 
559 


— 



In the determination of small amounts of manganese 
this method presents an advantage over Volhard's method 
in giving a more distinift end reaction. 

"The method can be used for iron and steel determina- 
tions if the usual precautions are taken to oxidise the 
carbon. But it is not so well adapted to these on account 
of the impradicability of taking large amounts for analysis. 
— journal of the American Chemical Society, xviii., April, 
1896. 

* This was so low as to necessitate filtering through asbestos in 
order to see end reaction by Volhard's method. 



METAL SEPARATIONS BY MEANS OF 

HYDROCHLORIC ACID GAS.* 

By J. BIRD MOVER. 

Introduction. 
The aftion of gaseous haloid acids upon metallic oxides 
and their salts is a field of investigation which, though 
not of recent origin, has been but lately developed. It 
was Debray {Comp. Rend., xlvi., logS, and Ann. Chem. 
(Liebig), cviii., 250) who first called attention to the 
volatility of molybdic acid in a stream of hydrochloric acid 
gas, with the formation of MoO(OH)2Cl2. 

E. Pechard (Comp. Rend,, cxiv., 173) applied this and 
showed that molybdic acid was completely eliminated 
and separated from tungstic acid by its volatility in a 
current of hydrochloric acid. Since that time nothing 
further has been done with single haloid acids, in gas 
form, until quite recently. Compounds have been decom- 
posed, salts volatilised, and separations made, by means 
of other gases and mixtures, which may be as effedive as 
hydrochloric acid, but are not devoid of trouble nor 
nearly so neat. 

Smith and Oberholtzer (yourn. Amer. Chem. Soc, xv., 
1), repeated and confirmed Pechard's work in regard to 
the separation of molybdic acid from tungstic acid, and 
in addition showed that gaseous hydrobromic, hydriodic, 
and hydrofluoric acids aded similarly. Later, Smith and 
Maas (Ztschr. Anorg, Chem., v., 280) made use of the 
volatilisation of molybdic acid for a close atomic mass 
determination of molybdenum. 

Smith and Hibbs (yourn. Amer. Chem. Soc, xvi., 578) 
showed that vanadium behaved like molybdenum. 
Hydrochloric acid gas completely eliminates vanadic 
acid from sodium vanadate. A little later they investi- 
gated the adion of hydrochloric acid upon the members 
of Group V. of the periodic system (Ibid., xvii., 6S2). 

The sodium salts of nitric, pyrophos-phoric, pyroarsenic, 
and pyroantimonic acids were used. They found nitrogen, 
arsenic, and antimony to be volatile in gaseous hydro- 
chloric acid, and made it the basis of a separation of 
phosphoric acid from nitric acid. Lead arsenate changed 
completely to chloride, the arsenic being volatilised, thus 
affording a good quick separation. Smith and Meyer 
{Ibid., xvii., 735) tried the adion of all the haloid acids 
upon the elements of Group V. of the periodic system. 
They worked with sodium salts and observed: — I. That 
nitrogen was expelled completely by all the haloid acids. 
II, That phosphoric acid was not aded upon. III. That 
arsenic acid was fully expelled by hydrochloric, hydro- 
bromic, and hydriodic acids, but only partially by hydro- 
fluoric acid. IV. That antimony was completely volati- 
lised by hydrochloric acid. There was no work done on 
bismuth. V. Vanadium went over completely in hydro- 
chloric acid, but only partially in hydrobromic and hydro- 
fluoric acids. VI. Columbium forms volatile produds 
with hydrochloric and hydrobromic acids. No knowledge 
of didymium was obtained. VII. Tantalum is only 
slightly volatile in hydrochloric acid. 

P. Jannasch and F. Schmidt (Ztschr. Anorg. Chem., 
ix., 274) repeated some of the work of Smith and Hibbs, 
in which they confirmed the separation of arsenic from 
lead. They anticipated a slight portion of my work, and 
in addition separated arsenic acid from iron, tin from 
lead, tin from copper, and tin from iron, in a stream of 
hydrochloric acid gas. 

The position of bismuth in the periodic system makes 
it natural to suppose that it too will be volatile in hydro- 
chloric acid gas. This I have shown to be true, and was 
thus enabled to separate it from lead and copper. The 
adion of hydrobromic acid on bismuth trioxide was also 
tried ; it formed the bromide and then volatilised. It 



* From author's thesis presented to the Faculty of the University 
of Pennsylvania for the degree of Ph.D., 1896. From the Joum. 
Amer. Chem. Soc, xviii., December, 1896. 



Crrmical News, i 
Jan. 29, 1897. I 



Metal Separations by means of Hydrochloric Acid Gas, 



53 



requires a higher temperature and longer aftion than with 
hydrochloric acid. Because of lack of time, I have been 
compelled to abandon the experiments instituted with a 
view of affedting separations, in atmospheres of hydro- 
bromic acid and hydriodic acid gas, and have confined 
my labours to hydrochloric acid gas. 

Method of Work. 

The hydrochloric acid gas was generated by dropping 
concentrated sulphuric acid from a separatory funnel upon 
concentrated hydrochloric acid contained in a three litre 
flask. The gas evolved at the ordinary temperature was 
dried by passing it through two sulphuric acid drying 
bottles and then through a calcium chloride tower, when 
it was considered sufficiently dry for the purpose. The 
substance to be aded upon was weighed out in a porce- 
lain boat, and the latter was placed in a combustion tube 
of hard glass. 

The tube had previously been rinsed with alcohol and 
then with ether to remove all moisture. The ether was 
removed by drawing a current of dry air through the tube. 
This tube was connedled to a two necked bulb receiver 
containing about 300 c.c. of distilled water. When 
working with arsenic 10 c.c. of niiric acid were added. 
The connedting tube from the combustion tube to the 
bulb receiver was made to enter the receiver and dip 
below the surface of the water, thus catching all volatile 
produds, as well as taking up the hydrochloric acid gas. 
To insure safety from the loss of volatile produdts, a small 
flask containing water was attached to the bulb receiver. 
The apparatus was controlled at both ends by stop-cocks. 
This is necessary to prevent backward sud\ion on discon* 
nedling the apparatus. After the readtion was completed 
the boat was removed to a sulphuric acid desiccator 
from which the air could be exhausted. In general, the 
procedure was similar to that employed by Hibbs 
(Thesis, 1896). 

I. — Behaviour of Antimony Trioxide, 
Antimony oxide, labelled chemically pure, was dis- 
solved in hydrochloric acid and precipitated with a large 
amount of water. After washing by decantation it was 
re-dissolved and re-precipitated. This procedure was 
repeated several tfmes, when it was precipitated by 
ammonium carbonate, washed, and ignited. The pure 
oxide obtained in this manner was subjedled to the adlion 
of hydiochloric acid gas, and it was found to volatilise 
completely. In each trial a one-tenth grm. of the oxide 
was adted upon. The temperature varied between 150° 
and 190° C. It was determined in the following way: — 
The combustion tube was slipped through two holes made 
in the sides o( a copper drying oven. 

A veiy slow current of gas was used as the antimony 
seemed to volatilise more readily and completely if the 
current was slow and the heat gentle. This 1 aitribute, 
on refledlion, to the fadt that 1 ignited the oxide too 
strongly (to a red heat) in its preparation. It dissolved 
with difficulty m concentrating hydrochloric acid. Lack 
of time prevented the repetition of this experiment and 
the separation of antimony from lead and copper, in 
which this substance was used. About eight hours was 
the time required for the volatilisation ; very probably a 
shorter time would be required if the oxide had been 
obtained by gentle ignition. 

II, — Behaviour of Lead Oxide. 

Pure lead oxide was obtained from re-crystallised nitrate 
by careful ignition. This oxide changed completely into 
chloride at the ordinary temperature, and it was only 
necessary to apply a gentle heat to complete the change 
and entirely remove the water formed. No volatilisation 
was noticed until a temperature of 225° was reached ; at 
this point the lead chloride slightly volatilised. 

1 think it possible to estimate lead as chloride, if the 
temperature is kept under 200°. A weighed amount of 
lead oxide was adted upon by hydrochloric acid gas in the 



cold for two hours, and theo heated sufficiently to remove 
all the water formed. 

The boat was cooled in the gas, and then placed in a 
sulphuric acid desiccator and allowed to stand one-half 
hour. It was then weighed. 

Experiments, 

Lead Lead Lead 

oxide chloride chloride 

taken. obtained, required. Difference) 

Grm. Grm. Grm. Grm. 

Experiment I. o'loiy 0*1267 o"i267 o'oooo 

„ II. o'lois o'i258 o"i265 —0*0007 

„ III. o*ii6g 0*1454 0*1447 +0*0007 

The lead chloride dissolved in hot water without residue, 

III. — The Separation of Antimony from Lead. 
The oxides were carefully weighed and thoroughly 
mixed in a porcelain boat. Hydrochloric acid gas was 
passed over them in the cold, until the lead oxide had 
been entirely changed to the chloride. It was then heated 
with the smallest flame obtainable from a fish-tail burner, 
placed about two inches below the tube. 

Antimony Lead Lead Lead 

trichloride chloride chloride chloride 

taken. taken. obtained, required. 

Grm, Grm. Grm. Grm. 

Experiment I. 0*1015 o*ii8g 0*1470 0*1482 

„ II. 0*1090 0*1021 0*1266 0*1272 

„ III. 0*1350 0-0852 0*1057 0-1062 

,, IV. 0*1250 0*1671 0*2069 0*2083 

The time required was seven hours. The lead chloride 
was immediately weighed. It dissolved completely in 
hot water, and this solution was tested by means of 
Marsh's apparatus for antimony, without finding the 
latter present. Experiment II. was slightly varied by 
first moistening the oxides with a drop of hydrochloric 
acid. 

IV. — Behaviour of Bismuth Oxide. 

Bismuth nitrate, as pure as could be obtained, was dis- 
solved in nitric acid and then thrown down with a large 
quantity of water. The precipitate was carefully washed 
by decantation. This operation was repeated several 
times. 

It was then dissolved in acidulated water and precipi- 
tated with ammonium hydroxide and ammonium car- 
bonate. This, on ignition, gave pure oxide, which, heated 
in a stream of hydrochloric acid gas, completely volatilised 
as chloride. Here the same treatment is necessary as 
obtained for antimony. A slow current of gas and a low 
heat were best adapted for the volatilisation (a tempera- 
ture of 130°, or roughly, the heat afforded by a fish-tail 
burner placed two inches below the combustion tube, with 
a flame an eighth of an inch high). The bismuth chloride 
sublimed nicely, forming a white crystalline mass beyond 
the boat, which could be readily driven along by a gentle 
heat. 

V. — The Separation of Bismuth from Lead. 

The same material was used as in the preceding experi- 
ments. The weighed oxides were thoroughly mixed in a 
porcelain boat. Usually the gas was allowed to adt in 
the cold for an hour, which changed the oxides completely 
to chlorides. 

The same conditions prevailed as under bismuth oxide 
alone. If an attempt was made to hasten the readtion by 
heating higher than 180°, a little lead would volatilise. 
This sublimate, slightly yellow in colour, would appear 
diredlly over the boat and could not be driven along the 
tube like bismuth ; hence it was readily detedled. 

The separation of bismuth from lead requires much 
care, as it is not as sharp as could be desired. It is also 
difficult to tell exadlly when the last traces of bismuth 
have been driven out of the boat, as there was no colour 
change to indicate it, both metals forming white chlorides. 
The separation is complete in from six to seven hours. 
At the end of the separation the position of the boat waa 



5^ 



Determination of Atomic Masses by the Electrolytic Method. {^"In'^^s^;*'* 



changed and the adlion continued ; if no further sublima- 
tion occurred it was cooled and removed to a desiccator. 
The weight was taken after standing one-half hour over 
sulphuric acid. With care bismuth can be separated 
from lead in this manner. 

Lead. Bismuth Lead Lead 

oxide trioxide chloride chloride 

taken. taken, obtained, required. Difference. 

Grm. Grm. Grm. Grm. Grm. 

Experiment I. o"ioi4 0*2020 0*1261 0*1264 — 0*0003 

„ II. 0*1006 00642 0*1252 0*1254 — 0-O0O2 

„ III. 0*1038 o 1003 0*1294 0-1302 — O'OOOS 
,, IV. 0*1412 0*1260 0*1759 0*1759 00000 

The chloride of lead dissolved completely in hot water. 
It showed no bismuth. The sublimate contained no lead. 

(To be continued). 



THE DETERMINATION OF ATOMIC MASSES 

OF SILVER, MERCURY, AND CADMIUM, 

BY THE ELECTROLYTIC METHOD.* 

By WILLETT LEPLEY HARDIN. 

(Continued from p. 41). 

Second Series. 
Experiments on Silver Acetate. 
The fadl that silver forms well-crystallised salts with a 
number of organic acids makes the comparison of the 
atomic mass of silver with the combined atomic masses 
of carbon, hydrogen, and oxygen, a matter of no great 
difficulty. From certain preliminary experiments the 
acetate of silver seemed to fulfil the conditions necessary 
for accurate determinations. 

Preparation of Silver Acetate, 
The purest commercial sodium acetate was dissolved in 
water, the solution filtered and re-crystallised. After 
three crystallisations the material was dissolved in pure 
water, and to the rather concentrated solution was added 
a solution of silver nitrate, prepared in the manner already 
indicated. The white curdy precipitate which separated, 
after washing with cold water, was dissolved in hot water, 
the solution filtered and evaporated to crystallisation. 
The silver acetate separated in brilliant sword-shaped 
crystals. After pouring off the solution the crystals were 
quickly rinsed with cold water and placed between filters 
to remove the adhering moisture. The material was 
allowed to remain in contadl with the filters only for a 
short time. It was then placed in a platinum dish, and 
when apparently dry the crystals were broken up into a 
finely divided condition and dried forty-eight hours in a 
vacuum desiccator. This work was carried on in a 
darkened room, and the silver acetate obtained was 
placed in a weighing tube, and kept in a desiccator in a 
dark place. 

Mode of Procedure. 

The method of operation was similar to that described 
under silver nitrate. After weighing the silver acetate 
its aqueous or cyanide solution was eleftrolysed and the 
weight of the resulting metallic silver determined. The 
results obtained from the aqueous solution were some- 
times vitiated by the separation of silver peroxide at the 
anode. To prevent this, potassium cyanide was sometimes 
added. The results, however, from the two solutions were 
praftically the same when no peroxide separated. From 
the aqueous solution the silver was deposited in a crys- 
talline form. The strength of current and time of adlion 
were the same as for silver nitrate. 

* Contribution from the John Harrison Laboratory of Chemistry 
No. 13. From the author's thesis presented to the Faculty of the 
University of Pennsylvania for the degree of Ph.D.— From the 
Journal of the American Chemical Society, xviii., p. 999. 



Ten observations on silver acetate reduced to a vacuum 
standard on the basis of — 

3-241 = density of silver acetate, 

10*5 = „ metallic silver, 

24*4 = „ platinum dish, 

8*5 = „ weights. 

and computed for the formula AgCzHsOj, assuming the 
atomic masses of carbon, hydrogen, and oxygen to be 
12*01, i*oo8, and 16 respedively, are as follows : — 





Weight 


Weight Atomic mass 




of AgC^HsOj. 


of Ag. 


of silver. 




Grms, 


Grm. 




I 


0*32470 


0*20987 


107*904 


2 


0*40566 


0*26223 


107-949 


3 


0*52736 


0-34086 


107-913 


4 


0*60300 


038976 


107-921 


5 


0-67235 


0-43455 


107-896 


b 


0-72452 


0*46830 


I07'9i6 


7 


0-78232 


0-50563 


107-898 


8 


0*79804 


0-51590 


107-963 


9 


0*92101 


0-59532 


107-925 


10 


1-02495 


0*66250 


107-923 




Mean .. 


.. = 107-922 






Maximum 


.. = 107-963 






Minimum 


. . = 107-896 





Difference .. = 0*067 
Probable error =i 0-005 

Computing from the total quantity of material used 
and metal obtained, we have 107-918 for the atomic mass 
of silver. 

Experiments on Silver Succinate, 

Silver succinate was prepared in a manner similar to 
that of silver acetate. The commercial C. P. succinic 
acid was re-crystallised three times; the ammonium salt 
was then prepared and its aqueous solution precipitated 
with a solution of pure silver nitrates. The precipitate 
of silver succinate was thoroughly washed by decantation 
with pure water and carefully dried. After drying for 
several hours in an air-bath at 50°, the material was 
ground in an agate mortar to a finely divided powder, and 
was then re-dried for twenty-four hours in an air-bath at 
a temperature of 60°. The white powder obtained in this 
way was placed in a weighing tube and kept in a desic- 
cator. 

The method of analysis was similar to that of silver 
acetate. A weighed portion of the material was dissolved 
in a little potassium cyanide in a platinum dish. After 
diluting with pure water, the solution was eleiStrolysed 
and the resulting deposit weighed. The strength of cur- 
rent and time of aftion were the same as for silver nitrate. 
The results computed for the formula C4H404Ag2 were 
not constant, and were invariably from one to two units 
lower than those obtained from silver nitrate and silver 
acetate. The material was then dried at a temperature of 
75°, but the results obtained were not satisfaiStory. 

The two most probable causes for these low results 
are: — 

First, the difficulty of removing the last traces of im- 
purities from a precipitate like that of silver succinate. 
The experience throughout this work has been, that to 
remove all the impurities from a finely divided precipitate 
by washing is almost impossible. 

Second, the difficulty met in drying material of this 
kind. This same difficulty was met in the experiments 
on silver oxide which, as shown by Lea, retained moisture 
up to 165°. 

Third Series. 
Experiments on Silver Benzoate. 

The preceding work on silver acetate and silver succi- 
nate shows the necessity of selecting compounds which 
form well-defined crystals. Perhaps no organic salt 
of silver fulfils the conditions necessary for accurate 
analysis better thati silver benzoate. 



CRBMtCAL NBWS, I 

Jan. 29, 1897. I 



Aluminum Analysis, 



55 



Preparation of Silver Benzoate. 

The purest commercial benzoic acid was re-sublimed 
three times from a porcelain dish into a glass beaker. 
The produ(5t thus obtained was dissolved in pure aqueous 
ammonia, and the solution evaporated to crystallisation. 
The ammonium salt was then dissolved in distilled water, 
and to the solution was added a solution of pure silver 
nitrate. The white precipitate of silver benzoate which 
separated was washed with cold water ; it was then dis- 
solved in hot water, the solution filtered, and evaporated 
to crystallisation. The salt separated in fine needles, 
which clung together in arborescent masses. After re- 
moving the liquid from the beaker, the crystals were 
quickly rinsed with cold water and placed between filters 
to remove the adhering moisture. When apparently dry 
they were broken up into small fragments and dried forty- 
eight hours in a vacuum desiccator. The material was 
then placed in a glass-stoppered weighing-tube and kept 
in a dark place. 

Mode of Procedure, 

The details of the method of operation are the same as 
those given under silver nitrate. A weighed portion of 
the material was dissolved in a dilute solution of potas- 
sium cyanide in a platinum dish. The solution was then 
eledtrolysed and the resulting metal weighed. The 
strength of current and time of aftion were the same as 
for silver nitrate. 

Before the results could be reduced to a vacuum 
standard it was necessary to determine the specific 
gravity of silver benzoate. This was done by means of a 
specific gravity bottle, the liquid used being chloroform. 
The mean of two determinations gave 2*082 for the spe- 
cific gravity of silver benzoate. 

Ten results on this compound, reduced to a vacuum 
standard on the basis of — 

2*082 = density of silver benzoate, 
io'5 = >» metallic silver, 

2I'4 = „ platinum dish, 

8-5 = „ weights, 

and computed for the formula C^HsAgOj, assuming i2'oi, 
I'ooS, and 16 to be the atomic masses of carbon, hydro- 
gen, and oxygen, respeftively, are as follows :— 

Weight "Weight Atomic mass 

of C^HjsAgOj. of Ag. of silver. 

Grms. Grm. 

1 0'4o858 o' 19255 107*947 

2 0*46674 0*21999 107*976 

3 0'484I9 0*22815 107*918 

4 0*62432 0*29418 107*918 

5 0*66496 0*31340 107964 

6 0*75853 0*35745 107*935 

7 0*76918 0*36247 107*936 

8 0*81254 0-38286 107*914 

9 0*95673 0*45079 107908 
10 1*00840 0*47526 107*962 

Mean .. ,. = 107*938 
Maximum .. = 107*976 
Minimum .. = 107*908 



Difference .. = o*o68 
Probable error = ^ 0*005 

Computing from the total quantity of material used 
and metal obtained, we have 107*936 for the atomic mass 
of silver. 

Summary. 

In discussing the work on the atomic mass of silver, 
two possible sources of error suggest themselves : — 

First, the hydrogen which is continually being set free 
in the process of eledtrolysis may, in part, be occluded by 
the metallic silver. As already pointed out, the metallic 
deposits were washed several times with boiling water, 
with the hope of removing any occluded gases ; but 
whether this effedted a complete removal of all the 
occluded gases was not determined. 



Second, the condensation of moisture on the platinum 
dish might be urged as a possible source of error. But it 
must be remembered that the dish was dried in the same 
manner each time and kept for several hours in a desiccator 
and that the atmosphere inside the balance was kept dry 
by means of several beakers of anhydrous calcium chlo- 
ride, and that the temperature of the balance room 
throughout the work was almost constant. Under these 
conditions there is but little chance of error from different 
amounts of moisture condensed. Moreover, the variation 
in the different weighings of the same dish was very 
slight. 

The advantages of the method are evident :— 

First, the great advantage of the method is its extreme 
simplicity. 

Second, the nature of the compounds used and of me- 
tallic silver renders them well adapted to weighing. 

Third, the method was such as to eliminate the errors 
incident to the ordinary gravimetric methods of analysis. 

Of the three series, the first is probably entitled to the 
greatest weight. That the silver nitrate was pure and 
free from moisture seems beyond question. However, 
the close agreement of the last two series with the first 
indicates that the acetate and benzoate of silver were 
also free from moisture. 

Giving equal weight to each of the three series, we 
have the following as the general mean computed from 
the separate observation : — 

Atomic mass of silver. 

First series 107*924 

Second „ 107*922 

Third „ 107938 

General mean =» 107*928 

Compijting the general mean from the total quantities 
of material used and metal obtained, we have :— 

Atomic mass of silver. 

First series 107*926 

"^ " 107*918 • 



Second 
Third 



107936 



General mean = 107*927 

Combining this with the first general mean we have 
107*9275 as the final result for the atomic mass of silver. 

(To be continued). 



ALUMINUM ANALYSIS.* 
By JAMES OTIS HANDY. 

Although the aluminum industry is not a large one in 
the sense that the iron industry is, it is growing very 
rapidly. The output of the United States in 1894 was 
550,000 pounds, and in 1895 it was about 850,000 
pounds. The Pittsburg Redudion Company, with works 
at New Kensington, near Pittsburg, Pa., and at Niagara 
Falls, N. Y., is the only American producer of aluminum. 
The material is made by the eledrolysis, in carbon-lined 
pots, of alumina dissolved in a fused bath of fluorides. . 
The produa of each pot is ladled out at intervals, and is 
graded according to the analyses of the Pittsburg Testing 
Laboratory, Limited. Some of the aluminum is sold as 
it is made, and some is alloyed to modify its physical 
properties. Alloys of aluminum with 3 per cent nickel, 
or with 3 to 7 per cent copper, or similar amounts of zinc, 
are very useful, on account of increased strength with 
only slightly increased specific gravity. The aluminum 
at present produced with the best ores available contains 
from — 



♦ From the Journal of the American Chemical Society, Sept., 1896. 



56 



Aluminum Analysis. 



Chemical News, 
Jan. 29, 1807, 



99 to 99'9 per cent of aluminum. 

o'3 to 0-05 per cent of silicon (combined and 

graphitic). 
0*50 to o'o per cent of copper. 
0*20 to 00 per cent of iron. 
Carbon is sometimes present in aluminum. 

Second grade aluminum contains 96 to gS per cent 
aluminum, silicon and iron making up the remainder. 
Aside from analyses of metallic aluminum, there are 
required, in the pursuit of the aluminum industry, analyses 
of alloys of copper, nickel, manganese, chromium, tung- 
sten, zinc, and titanium, with aluminum ; aluminum 
solders, containing tin, zinc, and phosphorus; aluminum 
hydrate, bauxite, and eie(ftrode carbons ; hydrofluoric acid 
and fluorides. 

Analysis of Commercial Aluminum. (95 to ggg per 
cent, pure). 

In the analysis of aluminum we are offered a choice of 
solvents. 

Solubility of aluminum : — Hydrochloric acid of 33 per 
cent (i.e., i part of hydrochloric acid of V2 sp. gr. to 
2 parts water) is a rapid solvent. 

Sulphuric acid of 25 per cent dissolves aluminum com- 
pletely on long boiling. 

Nitric acid of i-fg sp. gr. dissolves aluminum on pro- 
longed boiling. 

Acid mixture : — A mixture of the three acids, which we 
term " Acid Mixture" is made of — 

100 c.c. nitric acid of i'42 sp. gr. 

300 c.c. hydrochloric acid of i'2o sp. gr. 
600 c.c. sulphuric acid of 25 per cent. 

It is a very useful solvent for aluminum, because it sup* 
plies oxidising conditions during solution and so prevents 
loss of combined silicon as hydride. The sulphuric acid 
content of the acid mixture furnishes a means of rapidly 
dehydrating the silica. 

Sodium hydroxide solution of 33 per cent is a useful 
solvent when it is desired to separate the metallic im- 
purities from the bulk of the aluminum at once. Weaker 
solutions do not work as quickly or completely. Solution 
succeeds best in an Erlenmeyer flask. 

Fifteen c.c. of the sodium hydroxide solution suffice for 

1 grm. of aluminum. 

Commercial soda lye may be used if dissolved and 
filtered through asbestos. 

Other Reagents and Standard Solutions used in Aluminum 
Analysis. 

Sodium carbonate, chemically pure. 

Soda ash : " Solvay " soda ash, a saturated solution in 
water, Altered. 

Powdered zinc : pradically free from iron and copper. 

Fifteen per cent nitric wash : (15 parts 1*42 nitric acid 
to 85 parts water). 

Standard potassium permanganate : 5*76 grms. in 

2 litres. One c.c. equals 0005 grm. iron. 

Standard potassium cyanide: 45 grms. in 2 litres. One 
c.c. is made to equal 0*005 grm. copper. 

Special Apparatus. 

Two narrow glass tubes, graduated roughly, one to hold 
I grm. of powdered zinc, and the other i grm. of chemi- 
cally pure sodium carbonate. 

The evaporating dishes which are used are, preferably, 
about 4J inches in diameter, and are covered with 5-inch 
glasses. 

The Erlenmeyer flasks are of about 12-ounce capacity, 
and furnished with porcelain crucible covers. 

The Method. 
Determination of Silicon, Iron, and Copper in Commer- 
cial Aluminum. — One grm. of aluminum drillings is dis- 
solved in a 4J-inch evaporating dish in 30 c.c. of " acid 



mixture." If the drillings are thin it is best to add only 
15 c.c. at first. Placing cold water on the cover-glass 
sometimes prevents loss from too energetic foaming. 
Solution having been completed by warming slightly, 
evaporate quickly to strong fumes of sulphuric acid, and 
continue heating for five minutes. Experience will show 
on what parts of the hot plate these solutions can be 
evaporated without spattering at the time when aluminum 
sulphate begins to crystallise out. Remove the dishes 
from the plate by means of an iron fork, and in a few 
moments add to the contents of each 75 to 100 c.c. of 
water and 10 c.c. of 25 per cent sulphuric acid, break up 
the residue in each dish with a short heavy glass rod, 
and place the dishes back on the hot plate. Boil until 
all aluminum sulphate dissolves. Add to each dish i grm. 
of metallic zinc powder, measured. Be careful to pour 
the zinc into the middle of the liquid. If it touches the 
sides of the dish it sometimes becomes firmly fixed there. 
Keep the dish contents at 60° to 70° C. until the zinc has 
dissolved, leaving the iron reduced and the copper preci- 
pitated. Filter and wash well with hot water. Cool, 
titrate the filtrates withstandard potassium permanganate. 
One c.c. equals 0-50 per cent iron when i grm. of aluminum 
has been used. Placing new receivers under the funnels, 
treat each residue twice with hot 15 per cent nitric acid 
wash. Wash out with water, and in the solutions thus 
obtained titrate the copper with standard potassium 
cyanide, after adding saturated soda ash solution until the 
precipitated copper carbonate re-dissolves. The end point 
of the titration is very satisfactory. The cyanide solution 
should be standardised with copper of known purity in 
about the amount usually found, viz., 0*005 'o o'oio grm. 
The residue of silicon and silica are burned of! in num- 
bered crucibles, and each fused with i grm. of chemically 
pure sodium carbonate (measured). The crucible con- 
taining the fused mass is placed in 15 c.c. of water in the 
porcelain dish originally used, and 25 c.c. of 25 per cent 
sulphuric acid are added. Solution takes place quickly 
without separation of silica, and after rinsing out and 
removing the crucible, the solution is evaporated to five 
minutes fuming on the hot plate. After cooling add 75 
to 100 c.c. of water, and boil to disintegrate the silica. 
Filter and wash well with water. Burn off and weigh 
silica and crucible, treat with hydrofluoric acid and a 
drop of sulphuric acid if impurity is suspeded. Evaporate, 
ignite, and weigh again. Loss equals silica; calculate 
to silicon. 

Determination of Crystalline {Graphitic) Silicon in 
Aluminum. — Dissolve i grm. of aluminum in 30 c.c. of 33 
per cent hydrochloric acid (two parts of water to one of 
hydrochloric acid) in a platinum dish; add about 2 c.c. of 
hydrofluoric acid, stir, and filter at once through a No. o 
9 cm. filter, contained in a funnel which has been thinly 
coated with paraffin. Wash with water and burn off in a 
platinum crucible. Fuse with i grm. of sodium carbonate, 
cool in 15 c.c. of water in a four-and-a-half-inch evapo- 
rating dish. Add 20 c.c. of 25 per cent sulphuric acid. 
Rinse out the crucible. Evaporate to fumes, cool, add 
75 c.c. of water, boil up, and filter off the silica. Wash, 
ignite, and weigh. Calculate to silicon. 

The determinations of silicon, copper, and iron are the 
every-day methods of grading aluminum. It is recognised 
that sodium and carbon occasionally exist in aluminum, 
and they are determined by methods described. In cer- 
tain samples it is desirable to know the approximate per- 
centage of graphitic and combined silicon. These deter- 
minations are also described. We determine nitrogen, 
if present, by a special method. 

(To be continued). 



The Chemical Society,— At the last meeting of the 
Chemical Society it was announced that Mr. J. J. 
Tustin had made a donation of one thousand guineas to 
the Research Fund of the Society. 



I'RBMICAL NbWS, ) 

Jan. 29, 1897. I 



Passage of Electricity through Gases. 



57 



PROCEEDINGS OF SOCIETIES. 

PHYSICAL SOCIETY. 
Ordinary Meeting, January 22nd, 1897. 

Prof. Ayrton, Vice-President, in the Chair. 

Mr. Croft gave an exhibition of some simple apparatus. 

The exhibition included an ingenious form of clip to fit 
on an upright retort stand ; a nicol used for projefting 
the rings and brushes in crystals, with which it is suffi- 
cient to use the ordinary condenser of the lantern, the 
source of light having been moved further away from the 
lens than is usual ; some photographs showing caustics, 
conical refradion, and diflfradtion ; a stand for magnets, 
&c., when demonstrating the attradion and repulsion of 
poles ; a stand for the suspension of objects for experi- 
ments on diamagnetism ; a holder for X ray tubes, con- 
sisting of a spiral of wire fitting round the exhaustion tube 
of the bulb ; an X ray photograph taken by means of a 
Wimshurst machine ; a model of Michelson's interference 
experiment ; an arrangement to show subjedive colours, 
in which a double lantern is arranged to give two partly 
overlapping discs. A sheet of green glass is placed before 
one lantern, and the light of the other decreased till the 
illumination of the two discs is the same. The overlap 
then appears white, while the remainder of the uncoloured 
disc appears red. 

Prof. SiLVANUs Thompson said he was surprised that 
•' patent plate " was sufficiently good for Michelson's 
experiment. Had the author tried illuminating the discs 
in his subjedive effed experiment for a very short 
interval, so that the eye would not have time to wander 
from one disc to the other ? 

Mr. Griffith said that if you looked through a tube 
at one disc at a time, one appeared green and the other 
white. 

The Chairman said the point seemed to be, could you 
fatigue the eye simultaneously, or must it be successive ? 

Prof. SiLVANUS Thompson said two common one-inch 
microscope objedives were very suitable for projeding 
rings and brushes. 

Mr. E. C. Baly read a paper on the " Passage of Elec- 
tricity through Gases." 

In this paper, which is of a purely controversial nature, 
the author brings forward as arguments that eledrical 
condudion in gases is not of an eledrolytic nature the 
following: — (i) That the sign of the supposed gaseous 
ion is variable. (2) The initial resistance of a gas. (3) 
The invalidity of Ohm's law. (4) The permanence of the 
supposed gaseous eledrolyte. (5) That every mixture of 
gases must equally be an eledrolyte. (6) That the 
potential gradient in a vacuum-tube when the current is 
passing has been shown to be very uneven. It is very 
steep in the cathode glow, and is by no means a regular 
decline between the eledrodes. 

Prof. Armstrong said it was difficult to know from 
what point of view the author had treated the question. 
The first part of the paper consisted almost entirely of a 
criticism of Prof. J. J. Thomson's theory and experiments. 
Prof. Thomson, however, is not the only observer who 
has dealt with this subjed. The author's arguments 
seemed vitiated by the fad that he has looked upon the 
subjed from one very narrow standpoint only, viz., the 
ionic hypothesis, and Lord Kelvin, for instance, does not 
believe in the truth of the ionic hypothesis even in the 
case of liquids. Prof. Thomson has shown that the 
phenomena depend on the dryness of the gas, so that the 
condudion cannot depend on the gaseous molecule alone. 
In the case of condudion induced by a neighbouring dis- 
charge, this might be due to the expulsion of condensed 
vapour from the walls of the vessel. It would appear 
that in the dry state gases are not ele(5lrolytes. 



Mr, Enright said he thought it was not correA to say 
no work was done in eledrolysis. 

Prof. SiLVANUS Thompson said that the pursuit of the 
analogy between the condudivity in gases and liquids 
was apt to lead one too far. Thus, if you compare the 
condudion in a mixture of H and CI with eledrolysis, 
your analogy will be a false one unless you import into 
the term eledrolysis the idea of chemical separation as 
taking place in the solution. If a current separated a 
mixture of powdered zinc and sulphur, it could not be 
called a case of eledrolysis. 

Prof. Armstrong said an experiment of Prof. Dewar's 
was very instrudive. He had shown that if you cool the 
surface of a Crookes tube the discharge stops. It was 
quite inconceivable that at these low pressures the gas 
became liquefied, so that this experiment seemed to show 
that condudivity depends on the presence of a vaporous 
eledrolyte. 

Mr. Enright asked if Prof. Armstrong knew how the 
presence of an eledrolyte assisted condudion. 

In a communication Prof. J. J. Thomson said that in 
the decomposition of steam by a spark, the fad that in 
the tube as a whole the amount of steam decomposed is 
greater than the amount of gases liberated in a volta- 
meter in series was no objedion to the condudivity being 
eledrolytic. The only condition imposed by the laws of 
eledrolysis was that the excess of H or O at one terminal, 
and of O or H at the other, should correspond to the 
amount of eledricity passing through the tube. Thus, 
suppose in a water voltameter a number of metal parti- 
tions are fixed so that the current has to pass across these 
plates. Then at each plate H will be given off on one 
side and O on the other, and by making the partitions 
sufficiently numerous the total quantity of gases given off 
for the passage of a given current may be made as large 
as we please. The excess at the terminals would not be 
afTeded at all by these partitions. In the experiments 
made by Mr. Rutherford and himself (Prof. Thomson), 
they did not observe any polarisation when the con- 
dudivity was produced by Rontgen rays. With reference 
to Mr. Baly's objedions to the eledrolytic theory, (i) 
There is no reason to think that under conditions other 
than in solution the atom of hydrogen may not have a 
negative charge. (2) The eledrolytic theory leads us to 
exped that it would require a finite eledromotive force to 
send a discharge through a gas. Before such a discharge 
can take place, the molecules must be split up, and this 
requires an eledric field of finite strength. (3) In the 
case of a gas the eledric field has to ionise the molecules, 
/ so that an increase in the strength of the field will not 
only (as in the case of a liquid eledrolyte) increase the 
speed of the ions, but it will also increase their number, 
and thus the current will increase faster than the eledro- 
motive force. {4) The ion once used can again combine, 
and since the ionisation is done by the eledric field it can 
be again split up and used again. If, however, the ion- 
isation has been done by external sources, as, for example, 
by Rontgen rays, then we find that the condudivity 
decreases as the current passes. (5) There seems to be 
no reason on the eledrolytic theory why in a mixture of 
HCl and CI some of the current should not go through 
the chlorine. (6) A variable potential gradient would be 
produced if the ions moved with different velocities. Mr. 
Baly's process in the positive column appears to be the 
same as on the eledrolytic theory, minus the atomic 
charges. 

In a communication Prof. Schuster said : Mr. Baly 
criticises what he calls the eledrolytic theory, but direds 
his arguments against a form of the theory which is, as 
far as the writer knows, upheld by no one. Mr. Baly 
appears not to have read the original papers in which the 
fundamental points of the theory upheld by J. J. Thom- 
son and the writer (Prof. Schuster) are explained. If he 
had done so he could not have given as an objedion to 
the theory that the condudivity of a gas increases with 
the E.M.F. The essential difference between a liquid 



58 



Proximate Constituents of Coal. 



r CHEMICAL News, 
1 Jan. 29, 1807, 



and a gas is that in the liquid the number of ions is fixed 
by the chemical constitution of the liquid, while in a gas 
dissociation has first of all to be produced by the current 
itself, and hence the number of ions depends on the cur- 
rent. In the paper referred to by Mr. Baly, in which the 
fadt that when a spark is passed through a gas the gas 
ceases to insulate for some distance round the spark is 
described, the explanation that this was due to a difficulty 
of passage of the eledlricity from the eledlrode into the 
gas was especially disclaimed, the explanation given 
being substantially the same as that now given by Mr. 
Baly. Mr. Baly asks what becomes of the ions that are 
set free ? The answer, of course, is that they re-combine. 
The view that stratifications are due to compound mole- 
cules, and do not probably occur in pure gases, is not new. 
With reference to the author's statement about " measure- 
ments made by Wheatstone and J. J. Thomson prove 
that the eleAricity travels along the positive column from 
the anode to the cathode, and that its velocity is about 
half that of light," Prof. Thomson's results show that 
the breakdown of the insulating power of air takes place 
in the manner described, but this does not show anything 
as to what happens when the discharge has reached the 
steady state. Mr. Baly is quite wrong in the excess 
charges he assigns to different parts of the vacuum tube. 
Experiments on the excess charges can count for nothing 
unless they are done with continuous currents. Mr. 
Baly is further wrong in stating that the fall of potential 
is rapid in the glow ; on the contrary, it is very small 
in the glow, being very rapid in the dark space 
between the glow and the cathode. Mr. Baly adopts 
Prof. Thomson's view as to the formation of molecular 
chains, but in a form very difficult to accept. The whole 
foundation of Mr. Baly's theory is upset by his wrong 
assumptions as to the excess charges in different parts of 
the tube. 

The Author, in his reply, said, that on some points he 
had been misunderstood. He thought that the increase 
in conduftivity could not be due to vapour driven off from 
the sides, for ultra-violet light also produced such an 
increase. If Rontgen rays produce ionisation, then there 
ought to be a reduction in the density of the gas. 



NOTICES OF BOOKS. 

Rontgen Rays, and Phenomena of the Anode and Cathode. 
By Edward P. Thompson, M.E., E.E. With con- 
cluding Chapter by Prof. William A. Anthony. New 
York : D. Van Nostrand Company. 

This book is really a colledion of abstracts from 
papers dealing with ele<5trical discharges generally, 
and with the produdlion of X rays in particular ; it is well 
printed, and the illustrations are good, but there seems 
to be an idea in the mind of the printer that these latter 
need to be uniformly distributed through the book, with 
the result that within the first 70 pages or so we have no 
less than seven illustrations all referring to matter 
beyond pages 100. The first 60 pages are occupied 
with details of experiments on anodic and cathodic phe- 
nomena made long previous to Rontgen's discovery, the 
reason for this being, as the author points out in his 
preface, " that the student and general reader, whose 
objedt is to become acquainted with the properties of 
cathodic and X rays, might better understand them." 
This is very commendable, only we are rather afraid that 
the general reader will be in danger of confusion, while 
for the student the abstracts are far too meagre to be of 
much value beyond that of an index to the publications. 

The book contains far too much of the sensational 
newspaper charader that seems quite out of place ; 
for instance, a whole-page illustration of " Edison's 
beneficent X-ray exhibit " at the Eledrical Exposition in 
i8g6 is given on page 37, and is referred to on page 71 as 



an instance when " thousands of people, through the 
beneficence of Dr. Edison, were permitted to see the 
shadows of their bones surrounded by living flesh I " 

How this will enable either students or general readers 
to become better acquainted with X rays is difficult to 
comprehend. 

Another personal illustration, given on page 122, seems 
equally superfluous ; in this a Sprengel pump is shown 
of such an obsolete form, that if the physicist in question 
really used such an apparatus the wonder is that he ever 
produced any successful results at all. 

The abstracts of the most important papers are good. 
The review of Spottiswoode and Moulton's paper on 
Sensitive Discharges, Mr. Crookes's on Radiant Matter, 
and Lenard's Experiments, show that the author has 
thoroughly investigated the subjetft ; but again we must 
point out that they seem too technical for the general 
reader, and the student had far better refer to original 
papers for an intelligent knowledge of the experiments 
and the conclusions drawn from them. This cannot be 
got from an abstraft, no matter how carefully it may have 
been made. 

In several places there are statements that cannot fail 
to mislead an uninformed reader. For instance, on page 
47 Perrin's experiment to find out if the cathodic rays 
carry negative charges is given with illustrations, but it 
is not stated that this was fully demonstrated five years 
previously by Mr. Crookes in his Address before the 
Institute of Eledtrical Engineers. 

On page 96 a standard X-ray tube is shown with two 
concave cathodes, one at either end, and this is stated 
to have been " first proposed by Prof. Elihu Thompson." 
As this form of tube immediately suggested itself to many 
workers on the subjeft, it was proposed by numbers of 
people in the early days of X-ray work, and it is difficult 
to see the value of a claim to priority, especially in view 
of the fadt that it does not appear to have fulfilled the 
hopes of those who proposed it. With regard to the so- 
called "focus tube," which is really an unimportant 
modification of Mr. Crookes's incandescent platinum 
tube, it is said that King's College published a descrip- 
tion of it, and that Mr. Shallenberger was the first, as far 
as the author knew, to originate it. It is perfectly well 
known in England, at least, that the use of this tube was 
fully described by Mr. Jackson, of King's College, towhose 
energy much of the subsequent success of practical 
skiography is due, and it seems a pity that his name is 
not given. 

Great prominence is given to the calcium-tungstate 
screen for X-ray work. This material, although it pos- 
sesses the advantage of cheapness, is much inferior to 
barium or potassium platinocyanide. 

On the whole, we cannot but feel disappointed that the 
book, which, as the author says, is got up regardless of 
expense, should be of no more use than a compilation of 
abstracts. 



CORRESPONDENCE. 

REPORT OF COMMITTEE ON 
THE PROXIMATE CONSTITUENTS OF COAL. 

To the Editor of the Chemical News> 
Sir,— In the Chemical News (vol. Ixxiv., p. 292) there 
appeared a letter from Messrs. Cross and Bevan relating 
to the above report. To this I should have replied before 
had not my vacation intervened, during which I was 
unable to refer to the papers cited in the letter. 

As Secretary of the Committee, and mainly responsible 
for the drawing up of the Report, I would wish, in the 
first place, to take the onus of the shortcomings of the 
Report on my own shoulders, and, secondly, to disavow 
entirely any ihtentioh to disparage oi: belittle in any Way 



^rbmicalNkws, ) 
Jan. 29, 1897. I 



Chemical Notices from Foreign Sources, 



59 



the work of Messrs. Cross and Bevan on this subjedt. 
That the scope of their investigations had not been 
properly appreciated by me arose entirely from the fadt 
that I was not— as I ought certainly to have been— aware 
of the extent of their investigations. The perusal of 
their papers published in 1881, and in the Philosophical 
Magazine of 1882, has led me to realise something of 
what they have done toward furthering our knowledge of 
the relations of coal. I wish, therefore, to acknowledge 
the justice of their claim to priority for the method of 
attacking this problem by the aftion of chlorinating 
agents. — I am, &c., 

P. Phillips Bedson. 

The Durham College of Science, 
Newcastle-upon-Tyne, January 20, 1897. 



CHEMICAL NOTICES FROM FOREIGN 
SOURCES. 

NoTB.— All degrees of temperature are Centigrade unless otherwise 
expressed. 

Comptes Rendus Hebdomadaires des Seances, deV Academic 
des Sciences. Vol. cxxiv., No. 2, January ir, 1897. 

Obituary. — M. Loewy gave an account of the career 
and researches of Prof. B. A. Gould, the illustrious astro- 
nomer, of Cambridge (U.S.A.), who died on November 
26th last. The deceased was one of the first who suc- 
cessfully applied photography to the determination of the 
positions of the stars. 

The Academy proceeded to nominate a Commission 
charged with the appointment of a young French savant^ 
to whom will be granted the " encouragement " founded 
by the Royal Society of London in memory of the 
eminent physicist Joule. 

M. Berthelot presented to the Academy a volume 
entitled " Seriae intorne alia Teorie Moleculare ad 
Atomica ad alia Notazone Chimica," by S. Cannizzaro. 
This volume has been printed by occasion of the 70th 
anniversary of the birth of the eminent chemist, at the 
expense of an international subscription (July 13, 1896). 

Density of Ozone, — Marius Otto. — The density is ij 
times that of oxygen, i.e., i"6584. 

Decomposition of Metallic Sulphates by Hydro- 
cbloric Acid. — Albert Colson. — If the adtion of hydro- 
chloric acid upon sulphates is assimilable to heterogeneous 
dissociations two conclusions are necessary : — i. Sulphuric 
acid at about 15° will not attack lead chloride placed in an 
atmosphere of hydrochloric acid gas. The attack takes 
place only if the pressure is sufficiently reduced. Not 
merely is the principle of mechanical equivalence appli- 
cable to these phenomena of displacement, but Carnot's 
principle intervenes in a decided manner. 

Polymerisation of some Cyanic Compounds, being 
a Redtification of some of tbe Author's former 
Paper on Cy^C\^. — Paul Lamoult. — A thermo-chemical 
paper. 

A(5tion of Potassium Cyanide upon the Olides 
I — 4. — Edmond Blaise. — The author is seeking to effedt 
the synthesis of dimethyl 2-2 pentanedioic acid by the 
aftion of potassium cyanide upon bromo —2 — , ethyl 
— a — , pentanoate — 

^S3>CBr-CH2-CH2-COa-C3H5-KCN = KBr-|- 
/-iTT^>C - CHa — CHa 

CN CO2-C2H5, 

and saponification of the nitrile ether obtained. 

Phosphoric Ethsrs of AUylic Alcohol. — J. Cavalier, 
— The author is studying the monoallyl-phosphoric, 
diallylic and triallyl-phosphoric acids. 



A Difference between the " Top " and "Bottom" 
Yeasts. —P. Petit. — Top yeast consumes more than 
double the amidic nitrogen of bottom yeast, and, on the 
contrary, much ammonial nitrogen. 



MEETINGS FOR THE WEEK. 

Monday, Feb. ist.— Society of Arts, 8. (Cantor Leftures). "Material 
and Design in Pottery," by Wm. Burton, F.C.S. 
Tuesday, and.— Royal Institution, 3. "Animal Elearicity," by 
Prof. A. D. Waller, F.R.S. 

Society of Arts, 8. " The Progress of the British 

Colonial Empire during the past Sixty Years of 

Her Majesty's Reign," by the Right Hon. Sir 

Charles W. Dilke, Bart., M. P. 

Wednesday, 3rd.— Society of Arts, 8. "The Recommendations of 

the Recess Committee for the Development of 

Ireland's Industrial Resources," by The Right 

Hon. Horace Plunkett, M.P. 

Society of Public Analysts, 8. " The Composi- 

tion of Meat Extrafts and similar Produfts," 
by Otto Hehner. " The Distillation of Form- 
aldehyd from Aqueous Solution," by Norman 
Leonard, B.Sc, Harry M. Smith, and H. 
Droop Richmond. " Some Ana'yses of Water 
from an Oyster Fishery," " Remarks on Form- 
aluehyd " (postponed from last meeting), by 
Charles E. Cassal. ' 

Thursday, 4th.— Royal Institution, 3. " Some Secrets of Crystals " 
by Prof. H. A. Miers, F.R.S. 

Society of Arts, 8. " The Mechanical Produaioa 

of Cold," by Prof. James A. Ewing, M.A., F.R,S. 

Chemical, 8. "The Oxidation of Nitrogen," by 

Lord Rayleigh. " Researches in the Stilbene 
Series, 1.," by J. J. Sudborough, Ph.D. 
" Diortho -substituted Benzoic Acids. III. 
Hydrolysis of Substituted Benzamines," by 
J. J. Sudborough, Percy G. Jackson, and L. L. 
Lloyd. "Apparatus for Steam Distillation," 
by F. E. Matthews, Ph.D. " Oxidation of Sul- 
phurous Acid by Potassium Permanganate," by 
T. S. Dymond and F. Hughes. 

Friday, 5th.— Royal Institution, 9. " The Pidturesque in History,' 
by The Right Kev. The Lord Bishop of London, 

Saturday, 6th.— Royal Institution, 9. " Neglefted Italian and 
French Composers," by Carl Armbruster. 



LATELY PUBLISHED, Vol. III., 86a\pages, with 248 Illustrations 
price Iz zs. (completing the SECOND EDITION in Three 
Vols., £6 6s,). 

THE MANUFACTURE OF 

SULPHURIC ACID AND ALKALI, 

WITH THE COLLATERAL BRANCHES. 
By GEORGE LUNGE, Ph.D., Professor of Technical Chemistry 
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the Tyne Alkali Works, South Shields. 

" We hope that where this has not already been attended to, the 
three volumes will be forthwith added to the library of every college, 
technical school, and no less of every chemist (in the Continental 
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(SYNOPTICAL CIRCULAR ON APPLICATION). 



ODOROGRAPHIA: a Natural History of Raw Materials 

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CHEMISTRY OF THE ORGANIC DYE-STUFFS. By 

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This Laboratory, which has been founded by 
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Determtnaiion of A tomic Masses by the Electrolytic Method.. 



61 



THE CHEMICAL NEWS. 



Vol. LXXV., No. 1941. 



ON SOME CHROMATIC REACTIONS PRODUCED 

BY ORGANIC ACIDS, PRINCIPALLY 

TARTARIC, CITRIC, AND MALIC ACIDS. 

By E. PINERNA, 
Professor of Chemistry in the University of Valladolid. 

The reagent employed by me contains of a fresh solution 
of uaplitliol /? in concentiateiJ sulphuric acid (8-napthol- 
sulphuric acid). It is prepared with 0*02 grm. of naph- 
thol-/3 anii i c.c. of sulphuric acid, 1-83. 

Five centigrms. of each of the organic acids, or the 
residue left on the evaporation of their solutions, gradu- 
ally heated in a little porcelain capsule with a spirit flame, 
after having; added from 10 to 15 drops of the reagent, 
produce the following tints: — 

Tartaric acid, pure, gives at first a blue colour, and on 
continuing gradually to heat, it produces a very decided 
green colouration. On adding water to the liquid result- 
ing from the readion, after it has cooled (15 to 20 times 
its volume), the colour changes fo a persistent reddish- 
yellow. 

Citric acid, pure, gives an intense blue colour which 
does not change to a bright green even when it is heated 
gently for a long time. On pouring fifteen or twenty 
times its bulk of water on the liquid after cooling, the 
solution remains colourless or takes a light yellow 
colour. A small quantity of tartaric acid added to the 
citric acid is sufficient to produce the above-mentioned 
indigo-green colour. 

With pure citric acid we never obtain the strong green 
colouration so charaderistic of tartaric acid. A dull 
blue-green corresponds to the presence of 10 or 12 per 
cent of tartaric acid. 

Malic acid, pure, first gives a greenish yellow colour, 
and on continuing the gradual adion of heat a bright 
yellow colour. When the amount of acid is very small 
the colouration is well seen by shaking the capsule 
so that the liquid resulting from the readtion moistens the 
interior side, and the portion which remains on the sides 
is of a very perceptible yellow colour. The addition of 
water changes the colour to a bright orange. 

All the readions of these organic acids are charaderistic, 
and can be produced with great facility. 

It is only necessary to pay great attention to the 
employment of heat, and to notice the moment when any 
colouration commences, and then to remove the capsule 
from the fire, waiting till the change has terminated 
before re-commencing to heat (if necessary) until there 
appear the colours corresponding to each of the acids 
indicated above. 

The readions produced by other organic acids are 
different in colour and tint, but are not so charaderistic 
or brilliant as those already pointed out. One must pro- 
ceed to separation by solvents of the colouring matters 
produced. Other coloured readions are produced with 
nitrites, nitrates, and chlorates. On adding ten drops of 
the above described reagent to hve centigrms. of sodium 
nitrite with three or four drops of water, a very strong 
red colouration is produced, and the addition of water 
does not change it. 

On pouring ten drops of a solution of resorcin in sul- 
phuric acid (o-i grm. of resorcine in i c.c. of sulphuric 
acid at 66°) on five centigrms. of sodium or potassium 
nitrate, there is produced at first a red-brown colouration, 
and then a very intense violet, changing to orange on the 
addition of water. 



With potassium chlorate (two centigrms. of chlorate 
suffices) a very intense green colour is produced, changing 
to brown on the addition of water. 



THE DETERMINATION OF ATOMIC MASSES 

OF SILVER, MERCURY, AND CADMIUM, 

BY THE ELECTROLYTIC METHOD.* 

By WILLETT LEPLEY HARDIN. 

(Continued from p. 55). 

Part II. 
Determination of the Atomic Mass of Mercury, 
From ail the earlier dt-terininations Clarke gives 200 as 
the most probable value for the atomic mass of mercury, 
assuming oxygen equal to 16. 

Experiments on Mercuric Oxide. 
A large number of experiments were made with a view 
of determining the ratio of mercury to oxygen in mercuric 
oxide. The method proved to be unsatisfadory, although 
apparently very good results were obtained in some pre- 
liminary experiments. The cause of this close agreement 
of results will be explained in the details of the work. 

Preparation of Pure Mercuric Oxide. 
The purest commercial mercuric chloride was carefully 
sublimed from a porcelain dish into a glass funnel. The 
sublimed portion was dissolved in water, the solution 
filtered, and evaporated to crystallisation. The crystals 
were then thoroughly dried and carefully re-sublimed. 
The produd obtained in this way consisted of white 
crystalline leaflets which dissolved completely in water. 
Pure sodium hydroxide was then prepared by throwing 
pieces of metallic sodium on pure water contained in a 
platinum dish. To the pure sodium hydroxide was added 
a solution of mercuric chloride, the former always being 
in excess. The yellow mercuric oxide which separated 
was washed for several days by decantation with hot 
water. The material was then dried twenty-four hours in 
an air bath at 105°. 

Mode of Procedure. 
In a series of preliminary experiments made in the 
spring of 1895, a weighed portion of mercuric oxide pre- 
pared in the above manner was dissolved in a dilute solu- 
tion of potassium cyanide in a platinum dish. The solu- 
tion was then eledrolysed and the weight of the resulting 
metallic mercury determined. Inasmuch as the results 
obtained in these preliminary experiments were not re- 
duced to a vacuum standard, it was thought advisable to 
weigh the empty platinum dish after removing the metallic 
deposit in order that the two weighings might be made 
under approximately the same conditions. The results 
for the most part agreed very closely and differed very 
little from the results obtained by other methods. Six 
observations computed for the formula HgO, assuming 
the atomic mass of oxygen to be 16, are as follows : — 

Atomic Masses of Silver, Mercury, and Cadmium. 





Weight of HgO. 


Weight of Hg. 


Atomic mass 




Grm. 


Grm. 


of mercury. 


I 


0*26223 


0-24281 


200-05 


2 


0-23830 


0-22065 


200-02 


3 


0-23200 


0-21482 


200'o6 


4 


O-14148 


013100 


200 '00 


5 


0-29799 


0-27592 


200-03 


b 


0-19631 


0'l8l77 


200*02 




Mean 


=200*03. 





♦ Contribution from the John Harrison Laboratory of Chemisti-y 
No. 13. From the author's thesis presented to the Faculty of the 
University of Pennsylvania for the degree of Ph.D. — From the 
Journal of the American Chemical Society, xviii., p. 990. 



62 Determination of A tomic Masses by the Electrolytic Method. 



Cbbuical Mbw8, 
Feb. 5,1807. 



These results were seledled from a larger series. After 
making the above observations it was noticed that the 
platinum dish had gradually decreased in weight through- 
out the work. This decrease in weight indicated that 
the mercury deposit had formed an amalgam with the 
platinum dish, which was soluble in hot nitric acid. To 
ascertain whether such was the case or not the platinum 
dish, after weighing, was filled with a solution of the 
double cyanide of mercury and potassium and the solution 
eledtrolysed. On dissolving the mercury deposit in cold 
nitric acid a dark coloured film remained on the sides of 
the dish. The dish was then carefully washed, dried, and 
re-weighed, and found to be heavier than at the beginning 
of the operation, showing that the mercury had not been 
completely removed. The dark film was then dissolved 
in hot nitric acid and the dish again weighed. This last 
weight being less than that at the beginning showed that 
some of the platinum had been dissolved from the dish. 
The nitric acid solution of the dark film was evaporated 
to dryness and ignited to remove the mercury. The 
residue was dissolved in aqua regia, the solution evapo- 
rated to dryness, and enough water added to dissolve the 
small residue. A little concentrated ammonium chloride 
was then added to the solution, and the double chloride 
of ammonium and platinum separated as a yellow crystal- 
line powder. This proved conclusively that the mercury 
deposit had united with the platinum dish to form an 
amalgam which was soluble in hot nitric acid. Hence 
the results given for mercuric oxide are of no value in 
determining the atomic mass of mercury. 

A series of careful experiments was then made on the 
oxide dried at different temperatures. To avoid any error 
from the amalgam which formed with each deposit, the 
platinum dish was weighed at the beginning of each observa- 
tion, the temperature and barometric pressure being noted 
at the same time. The results obtained from the oxide 
dried at a temperature of 105° gave from 180 to 185 for 
the atomic mass of mercury. The material was then 
dried at a temperature of 125°, but the increase in the 
amount of mercury obtained was very slight. Fmally, 
with material dried at 150°, the results obtained for the 
atomic mass of mercury were all below 195°. 

The most probable causes for these low results are: — 

First, the difficulty of removing the last traces of 
alkalies from the mercuric oxide. 

Second, the difficulty met in the complete removal of the 
moisture from an amorphous precipitate. This difficulty 
as well as the first was referred to in the experiments on 
silver oxide. 

Third, mercuric oxide does not form a clear solution 
with potassium cyanide. There seems to be a slight re- 
dudtion of the oxide to the metallic state. It is difficult 
to determine whether this reduced portion unites com- 
pletely with the metallic deposit or is partially removed 
in the process of washing. The latter is probably true, 
and it may be that a different method of analysis would 
give more accurate results for this compound. 

First Series. 
Experiments on Mercuric Chloride. 
The material used in this series of experiments was 
prepared from the commercial C. P. mercuric chloride. 
The product was first dissolved in water, the solution 
filtered and evaporated to crystallisation. The crystals 
were dried and carefully sublimed from a porcelain dish 
into a glass funnel. The sublimed portion was dissolved 
in water, the solution filtered and evaporated to crystal- 
lisation. These crystals were dried as before and care- 
fully re-sublimed. The material was then placed in a 
weighing tube and kept in a desiccator. 

Mode of Procedure. 

The method of operation was similar to that already 

described under the different compounds of silver. A 

weighed portion of the mercuric chloride was dissolved in 

a little potassium cyanide and the solution ele^rolysed. 



The deposit was washed and dried and handled in every 
way like the deposits of silver. The strength of the cur- 
rent and time of aftion were as follows: — 

Time of a£lion. Strength of current. 

4 hours N.Dioo=o'02 amperes. 

N.Dioo = o-05 „ 



N.Dioo = oio 
N.Dioo = o-30 



A current of gradually increasing strength deposits the 
mercury in extremely small globules, which can be 
washed and handled more easily than the larger globules 
obtained by using a strong current at first. In cases 
where more than one-half grm. of metal was deposited 
the strong current was allowed to &&. two hours longer. 

Ten results on mercuric chloride reduced to a vacuum 
standard on the basis of 

5"4i = density of mercuric chloride, 
^3'59= II II metallic mercury, 
2i'4 = ,, ,, platinum dish, 

8*5 = ,1 11 weights, 

and computed from the formula HgClj, assuming 35*45 
to be the atomic mass of chlorine, are as follows : — 



I 
3 

3 
4 
5 
6 

7 
8 

9 
10 



Weight 
of HgClj. 

Grms. 
0-45932 

o"54735. 

056002 

063586 

0-64365 

073281 

0-86467 

1-06776 

1-07945 

I -5 1402 

Mean .. 

Maximum 

Minimum 



Weight 
ofHg. 
Grm. 
0-33912 
0-40415 
0-41348 
0-46941 
0-47521 
o'54ioi 
0-63840 
078825 
079685 
1*11780 

= 200' 
= 200 
= 199 



Atomic mass 
of mercury. 

200*030 
200-099 
200-053 
199-947 
200-026 
199-988 
200-838 
199-946 
199-917 
200*028 



006 
099 
917 



Difference .. = 0-182 
Probable error =^o-oii 

Computing from the total quantity of material used and 
metal obtained we have 199-996 for the atomic mass of 
mercury. 

Second Series. 

Experiments on Mercuric Bromide. 

The bromine used in these experiments was prepared 

by distilling the commercial C. P. bromine twice over 

manganese dioxide. Any trace of chlorine which might 

be present would be removed by this method. 

Preparation 0/ Mercuric Bromide. 
Fifty grms. of metallic mercury were placed in a beaker 
and covered with water. Pure bromine was then added 
until the mercury was completely saturated. The con- 
tents of the beaker were then digested with hot water 
until the mercuric bromide dissolved ; the solution was 
filtered and evaporated to crystallisation. The white 
crystals of mercuric bromide which separated were 
thoroughly dried and carefully sublimed from a porcelain 
dish into a glass funnel. Only the middle portion of the 
sublimate was used in the experiments. The produdl 
obtained in this way consisted of brilliant crystalline 
leaflets which dissolved completely in water. The 
material was kept in a weighing tube in a desiccator. 

Mode of Procedure. 
The method of analysis was exadly like that described 
under mercuric chloride. A weighed portion of the mer- 
curic bromide was dissolved in dilute potassium cyanide 
in a platinum dish. The solution was then eleArolys«d 



Chrmical Nsws, 
Feb. St 1S97. I 



Metal Reparations by means of Hydrochloric A cid Gas, 



63 



and the resulting metal weighed. The strength of current 
and time of adtion were the same as for mercuiic chloride. 
Ten results on mercuric bromide reduced to a vacuum 
standard on the basis of 

5-92 = density of mercuric bromide, 
I3"59 = II metallic mercury, 

21*4 = ,, platinum dish, 

8*5 = „ weights, 

and computed for the formula HgBrj, assuming 79'95 to 
be the atomic mass of bromine, are as follows : — 





Weight 


Weight Atomic mass 




of HgBfj. 


ofHg. 


of mercury. 




Grtns. 


Grm. 




I 


070002 


0*38892 


199898 


2 


0*56430 


0*31350 


199-876 


3 


0-57142 


0-31750 


199-938 


4 


077285 


0-42932 


199-832 


5 


0*80930 


0-44955 


199814 


6 


0*85342 


O-474I6 


199 91 1 


7 


1*11076 


0*61708 


199-869 


8 


1*17270 


065145 


199 840 


9 


1*26186 


0-70107 


199899 


10 


1*40142 


0*77870 


199-952 




Mean .. 


.. = 199-883 






Maximum 


.. = 199*952 






Minimum 


.. = 199*814 





Difference .. = 0*138 
Probable error =io-oio 

Computing from the total quantity of material used and 
metal obtained, the atomic mass of mercury is 199*885. 
(To be continued). 



METAL SEPARATIONS BY MEANS OF 

HYDROCHLORIC ACID GAS.» 

By J. BIRD MOVER. 

(Continued from p, 54). 

VI. — Behaviour of Cupric Oxide. 
Pure copper nitrate was made by re-crystallisation. It 
was then ignited in a porcelain crucible at a dull red heat, 
until it became constant in weight. The pure black 
oxide was then subjei5ted to the adion of hydiochloiic 
acid gas. In Experiment I., the boat containing the 
oxide was heated at the outset to 175°. It was taken out 
after two hours, placed over sulphuric acid for half-an-hour, 
and weighed. The weight showed that the copper oxide 
had hardly been aded upon. It had only been super- 
ficially changed to chloride. It was then moistened with 
two or three drops of hydrochloric acid, dried in a rapid 
current of the gas, and heated two hours longer. This 
resulted in the complete transformation into chloride. 
The anhydrous chloride thus obtained, liver brown in 
colour, was placed in a desiccator from which the air was 
exhausted. This was done to remove all the gas that 
might be retained, and prevented a too rapid absorption 
of moisture. 

Copper chloride absorbs moisture, but not so rapidly as 
to prevent weighing in this form : — 

Copper Copper 

oxide chloride 

taken. obtained. 

Grm. Grm. 



Experiment I. 

II. 

.. IlL 



0*1011 

0*1025 
0*1034 



0*1708 
0*1726 
0-1756 



Copper 
chloride 
required. 

Grm. 
0*1713 
0-1736 
0*1752 



Difference, 
Grm. 

— 0*0005 

— 0*0010 
4-0*0004 



In Experiment II. the change was completed in the 
cold by prolonged adlion through four hours. It was 
then heated about ten minutes at the end to drive out 
the moisture that had formed. In all the experiments 
cited, the copper chloride, after weighing, was found to 
dissolve completely in cold water. 

VII. — The Separation of Antimony from Copper. 

The same material was used as in the preceding 
experiments. 

The weighed oxides were thoroughly mixed. The 
antimony was completely volatilised, leaving copper 
chloride which was weighed as such. The volatile anti- 
mony chloride was caught in the bulb receiver at the end 
of the tube. The bulb and tube were washed out with 
acidulated water into a beaker, and the antimony thrown 
down with hydrogen sulphide. The antimony sulphide 
was filtered, thoroughly washed, and while moist dis- 
solved in strong hydrochloric acid. The hydrogen sulphide 
evolved was conduced into bromine water and oxidised 
to sulphuric acid, which was estimated as usual and the 
antimony calculated. 

The length of time required was eight hours. On 
several occasions the experiment was interrupted at the 
end of four hours, but invariably the separation was 
incomplete, and on dissolving out the copper chloride 
formed, black copper oxide and white antimony oxide 
were plainly evident. In some cases the mixture of 
oxides was moistened with a couple of drops of hydro- 
chloric acid, and then evaporated down in a stream of 
acid gas by heating the tube over a water-bath. This 
treatment seemed to facilitate matters, but it is not alto- 
gether advisable, because the copper chloride has a 
tendency to creep over the sides of the boat. It is quicker 
in the end to separate them in the dry condition, allowing 
plenty of time for the readlion. The copper chloride 
obtained was perfedly soluble in cold water and con- 
tained no antimony. It could readily be changed to 
oxide and weighed if thought necessary. 



Experiment I 
„ II 
., Ill 



Antimony 

trioxide 

taken. 

Grm. 

. o-io68 

. 0-1062 

. 01022 



IV. 0*1198 



Copper 
oxide 
taken. 
Grm. 
0-1040 
01053 
O 1020 
0-1020 

Antimony 

trioxide 

taken. 

Grm. 

0-1068 



Copper Copper 

chloride chloride 

obtained, required. Difference. 



Grm. 
0*1750 
0*1774 
0-1726 
0-1722 

Antimony 
trioxide 
found. 
Grm. 
0-1059 



Grm. 

0-1745 
0-1784 
o 1728 
0-1728 



Grm. 
-{-00005 

— O'OOIO 

— 00002 

— 00006 



Difference. 

Grm. 
-f 0-0009 



Experiment I. 

VIII. — The Separation of Bismuth from Copper. 
The pure oxides were mixed and treated as direded 



under bismuth and lead. 

Copper 
oxide 
taken. 
Grm. 
0-1030 
0*1004 
0-1026 
o-ioig 



Bismuth Copper 
trichloride chloride 
taken, obtained. 



Copper 

chloride Difference, 
required. 



Experiment I. 

II. 

„ III. 

IV. 



Grm, 

— 0-0007 

— 00012 
-t-00003 

— 00008 



♦ From author's thesis presented to the Faculty of the University 
of Penns>lvania for the degree of rh.D., 1896. From tbe Journ. 
Amer. Chem. Soc, xviii., December, i8gG. 



Grm. Grm. Grm. 

0-1069 0-1738 0-1745 

0*1077 0-1701 0-1713 

o-iobo 0-1741 0*1738 

0-1058 0*1718 0-1726 
Bismuth Bismuth 
trioxide trioxide 

obtained. required. Difference. 
Grm. Grm. Grm. 

Experiment I. 0-1076 0-1069 +00007 
The time required in each of these trials was seven 
hours. It seemed to be advantageous to raise the tem- 
perature and heat sharply for about ten minutes at the 
end, to insure the complete removal of the bismuth. 

Moistening with acid helped the reaftion, but subjeded 
it to the same danger of creeping as noted under antimony 
and copper. 



64 



Metal Separations by means of Hydrochloric A cid Gas, 



;hbuical News, 
Feb. 5, 1897. 



The bismuth was estimated as follows : It was washed 
out of the tube and bulb with acidulated water, and then 
precipitated as sulphide. The bismuth sulphide was 
filtered, washed, and dissolved in nitric acid. It was 
thrown out of the solution with ammonium hydroxide 
and ammonium carbonate as hydrated oxide, and then 
filtered, dried, and ignited. It was weighed as oxide. 
The residue of copper chloride in the boat dissolved in 
cold water and showed no bismuth. 

IX. — Action of Gaseous Hydrochloric Acid on Sodium 
Pyroarsenate. 

Hibbs (yourn. Amer. Chem. Soc, xviii., 1044) showed 
that arsenic was completely volatilised from sodium pyro- 
arsenate, leaving weighable sodium chloride. In fad, so 
clean was the elimination of arsenic that he made it the 
basis of an arsenic atomic mass determination, with 
admirable success. 

In working up the separation of arsenic from other 
metals it was necessary to start with the pure sodium 
salt. After purification I decided to test it, by weighing 
the salt produced by the aiJiion of the acid gas upon it. 
Several determinations gave close results, proving the 
salt pure. 

Chemically pure arsenate was procured. It was 
re-crystallised and then ignited (not too strongly) for an 
hour. The pyroarsenate obtained was used in precipi- 
tating the various arsenates investigated. 





Sodium 

pyroarsenate 

taken. 


Sodium 
chlo.-ide 
obtained. 


Sodium 
chloride 
required 


Experiment I. 
II. 


Grm. 
0'202I 
0'1039 


Grra. 
01330 
0*0691 


Grm. 

0-1335 
o'o686 



X. — The Separation of Arsenic from Copper. 

Pure sodium pyroarsenate was used to precipitate the 
copper salt. 

Copper sulphate was re-crystallised five times, a few 
good crystals were dissolved and the two solutions mixed. 
A green copper arsenate was precipitated. It was washed 
and dried at 100°. Salkowski (yourn. Prakt. Chem., civ., 
129) observes that copper arsenate still contains water 
above 130°. My salt had the composition — 
CujAsaOs + 2H2O. 

Hydrochloric acid gas completely changes it in the 
cold to chloride. A slight heat drives out the arsenic 
and water and leaves a brown anhydrous copper chloride, 
which can be weighed as such. Care was taken to 
remove all the acid gas before weighing. 

The arsenic was washed out of the bulb into a beaker ; 
this was warmed with nitric acid to insure oxidation, and 
then it was precipitated from an ammoniacal solution 
with *' a magnesia mixture." It was weighed as 

MgaAsjO;. 

" Copper 

chloride 
obtained. 

Grm. 
o'o850 
0*0998 
0*0860 



Experiment I. 

II. 

„ III. 

„ IV. 

V. 



Copper 
arsenate 

taken. 

Grm. 
0*1067 
0*1240 
0*1072 
0*1155 
0*1042 



00924 
0*0832 



Copper 
chloride 
required. 

Grm. 
0*0851 
0*0991 
0*0856 
0*0923 
0*0833 



Difference. 
Grm. 

— 0*0001 
+ 0*0007 
-f 0*0004 
-fOOOOI 

— 0*0001 



Experiment I. AS2O5 obtained, 0*0498 grm. ; AS2O5 
required, 00487 grm. 

The residue of copper chloride completely dissolved in 
water. It showed no arsenic when tested in a Marsh 
apparatus. 

XI. — The Separation of Arsenic from Silver, 

Silver arsenate was made by precipitating silver nitrate 

with sodium arsenate. Care was taken to have the 

nitrate in excess. The reddish-brown arsenate of silver 

was washed with boiling water, until the washings no 



longer showed silver when tested with hydrochloric acid. 
It was dried at 110°. 

As was expeded, the acid gas attacked it even in the 
cold. In fadt the adion was so vigorous that a couple 
of analyses were spoiled by spattering. The trouble 
arose from the fad that the arsenate was not finely 
powdered. Heat was generated in the readion suffi- 
ciently to send over a portion of the water formed. 
Experiment I. was run in the cold for one hour and then 
heated sharply for a few minutes to expel the arsenic and 
water. The result was only 0*46 per cent too high, but 
indicated that the salt should be heated longer, and not 
necessarily as high to remove all the arsenic. 

The succeeding experiments were heated from one to 
two hours at 150° with better results : — 





Silver 


Silver 


Silver 






arsenate 


chloride 


chloride 






taken. 


obtained. 


required. 


Difference 




Grm. 


Grm. 


Grm. 


Grm. 


Experiment I. 


0*2542 


0*2381 


0*2363 


+ o*ooi8 


n. 


0*2325 


0*2163 


0*2l6l 


+ O*0002 


in. 


0*2084 


0*1952 


0*1938 


+ 0*0014 


IV. 


02070 


0*1927 


0*1924 


+ 0*0003 



Experiment I. Ag obtained = 70*45 per cent ; Ag 
required = 69 '99 per cent. 

The residues in Experiments II., III., and IV. were 
dissolved and tested for arsenic. None was found. 

XII. — The Separation of Arsenic from Cadmium. 

Chemically pure cadmium sulphate was precipitated by 
a solution of sodium pyroarsenate. Stirring brought out 
a gelatinous arsenate, which changed by additional stir- 
ring to a granular salt. This was thoroughly washed and 
dried at 110°. It had the composition Cd3As208 + 2H20. 
Salkowski (loc. cit.) observes that a red heat is necessary 
to fully dehydrate this salt. 

The moisture and arsenic were completely expelled at 
150°, leaving a uniform mass of cadmium chloride. It 
was weighed as such after standing over sulphuric acid 
for one-half hour. The arsenic was determined as usual. 

CdgAs20g4- Cadmium Cadmium 

2H2O chloride chloride 

taken. obtained, required. DifTerence. 

Grm. Grm. Grm. Grm. 

Experiment I. 0*2359 0*1965 0*1977 —0*0012 

„ II. 0*1166 0*0968 0*0968 O'OOOO 

,, III. 0*1030 0*0857 0*0855 +O*O002 

„ IV. o"ii38 0*0947 0*0946 +0*0001 

„ V. 0*1043 0*0870 00867 +0*0003 

CdgAs208+ As^Os AS2O4 

2H5JO taken, obtained, required. Difference. 

Grm, Grm. Grm. Grm. 

Experiment I. 0*2359 0*0813 00822 0*0009 

The cadmium chloride dissolved perfedly in water, and 
showed no arsenic when tested in a Marsh apparatus. 

XIII. — The Action of Hydrochloric Acid Gas on 
Ferric Oxide. 

Pure oxide of iron was heated in a stream of acid gas. 
The behaviour of iron is rather peculiar, as it very readily 
changes into chloride, and then only partially volatilises 
On heating to 200° the greater part is driven over as flaky 
crystals of ferric chloride. The remainder consists of a 
white mass, which refuses to go over on prolonged adion 
and also on raising the temperature. 

This residue was soluble in water and did not read 
with potassium thiocyanate, but immediately gave a blue 
precipitate with ferricyanide. Redudion was therefore 
evident; this is also noted by Jannasch and Schmidt 
{loc. cit.). The temperature at which ferric chloride 
usually goes into the ferrous condition is above looo'^. 

Care was taken to prepare perfedly pure hydrochloric 
acid gas. Chemically pure acids were used to this end. 
The adion, however, was the same in all cases. 



CasMicAt mbws, 

Feb. 5, 1897. I 



Nickelo-nickelic Hydrate. 



XIV.— The Separation of Arsenic from Iron. 

Chemically pure ferrous ammonium sulphate was care- 
fully oxidised with nitric acid, it was taken up in water, 
filtered, and then crystallised several times. The best 
crystals were seleded, and a solution made to precipitate 
the arsenate. A white precipitate tinged with yellow was 
formed. It was washed by decantation and then filtered 
and washed until the washings no longer gave Prussian 
blue with ferrocyanide. It was then dried and gently 
ignited. 

The acid gas adts on it quickly in the cold, and it 
becomes a light green liquid. In evaporating off the 
moisture the chloride of iron was carried over with the 
arsenic. 

In a second trial, with the temperature lower and occa- 
sionally removing the source of the heat altogether, when 
ebullition threatened to cause spattering, ferric chloride 
was obtained without loss. This v/as gradually heated a 
little higher to remove all the arsenic. 

The chloride of iron was dissolved, oxidised, precipi- 
tated with ammonium hydroxide, and estimated as usual. 
The result was fair, and the produdl tested showed the 
absence of arsenic, but all succeeding experiments failed. 
Either the substance spattered or the iron went along 
with the arsenic. 

Jannasch and Schmidt {loc. cit.) separated arsenic from 
iron by placing their material in a large hard glass bulb 
and evaporating down to dryness with nitric acid in an 
air current. This is not applicable when a porcelain 
boat is employed. They then volatilised the arsenic in 
hydrochloric acid gas at 120°. 

(To be continued). 



NICKELO-NICKELIC HYDRATE, Ni304.2H20. 
By WILLIAM L. DUDLEY. 

In studying the adlion of fused sodium dioxide on metals, 
I have obtained interesting crystalline compounds, some 
of which at least have never been described. Only one of 
them has been carefully investigated, and it proves to be 
nickelo-nickelic hydrate, having the formula Ni304.2H20. 

It is prepared by fusing sodium dioxide in a nickel 
crucible with metallic nickel at a cherry-red heat. The 
aftion of the oxide upon the nickel proceeds with moderate 
rapidity, and in a few minutes scaly crystals appear 
floating in the fused mass. The crystals multiply steadily 
until, in the course of an hour, the contents of the crucible 
is thick with them, and comparatively little liquid 
remains. After cooling, the crucible is submerged in a 
beaker of distilled water, and the undecomposed sodium 
dioxide, together with the sodium oxide, dissolves out, 
leaving the crystals which rapidly settle to the bottom of 
the liquid. The crystals should be washed several times 
with boiling water by decantation, and finally thrown in a 
filter. It is quite difficult to wash out all the alkali, which 
adheres with unusual persistence. Probably the best 
plan to adopt is to put the crystals in a Soxhlet extradlion 
apparatus, and wash with water until no colouration is 
obtained with phenolphthalein. I'his requires about fifty 
hours of continuous washing. The crystals should then 
be dried at no° C, and a magnet passed carefully through 
them to remove any particles of metallic nickel which 
may have eroded and not been completely adted upon. 

The crystals are lustrous and almost black, with a 
slight brown-bronze hue. They are soft, and grind in a 
mortar much like graphite. The crystals seem to be 
hexagonal plates, but measurements of the angles have 
not been made. They dissolve slowly in acids, forming 
nickelous salts. Hydrochloric acid evolves chlorine ; 
sulphuric and nitric acids, oxygen. They are insoluble 
in water and in solutions of the alkalies. The compound 
is not magnetic. The specific gravity is 3*4115 at 32° C. 



At 130° C. the compound does not undergo decomposi- 
tion, but at about 140° C. it begins to lose weight ; at 
240° C. the weight remains constant. At a red heat 
further loss is sustained and the residue remaining is 
nickelous oxide. The loss from 130° C. to 240° C. is due 
to water driven off, and at a red heat this loss is due to 
the evolution of oxygen. 

The compound proved to be Ni304.2HaO, as is shown 
by the results of the analysis : — 

Loss of HaO on heating from 130° C. to 240° C. : — 

Per cent. 

First determination 13-00 

Second „ I3'i3 

Theory for Ni304.2H20 13-05 

The residue remaining after heating to 240° C. is 
Ni304. On heating this residue to redness the loss of 
oxygen was found to be: — 

Per cent. 

Loss of oxygen 663 

Theory 6*67 

The total loss of water and oxygen obtained on heating 
the compound from 130° C. to redness was :— 

Per cent. 

First determination 18-gi 

Second „ 18-88 

Theory for Ni304.2H20 18-86 

The oxygen given off on heating to redness was deter* 
mined by calcining the compound in an atmosphere of 
carbon dioxide, and colledting in Schiffs apparatus over 
potassium hydroxide solution. The result gave : — 

Per cent. 

Oxygen 5-93 

Theory for Ni304.2H20 5-84 

The nickel was determined and found to be : — 

Per cent. 

Nickel 6367 

Theory , 63-72 

In all of the calculations the atomic weight of nickel 
was taken to be 58-56, and oxygen 16. 

The compound made in a nickel crucible of commerce 
is not pcrfedlly pure, as the sample obtained was found 
to contain o-yr per cent of cobalt, the presence of which, 
however, would make no appreciable difference in the 
results of the analyses. No method has been found for 
freeing the compound from this impurity, and it appears 
at present as if the only plan would be to use a chemically 
pure nickel crucible in making it, for no crucible will 
withstand the adion of fused sodium dioxide. Porcelain, 
iron, silver, gold, and platinum crucibles are rapidly 
attacked. 

The presence of water in this compound seems curious, 
but it may be due to the presence of sodium hydroxide in 
the sodium dioxide. Again it may be due to the water 
added to dissolve the soluble residue from the crystals. 
The first explanation seems to be the more plausible since 
the crystals are formed in the mass while it is fused, and 
they are not produced upon the addition of the water. If 
such is the case it would seem that the water driven off 
between 130° C. and 240° C. is from the breaking down of 
a true hydrate, rather than the expulsion of water of 
crystallisation. 

A cobalto-cobaltic hydrate, C03O4.2H2O, has been 
described (Genth and Gibbs, Amer. yourn. Sci., xxiii., 
257), but it was obtained by exposing to moist air, C03O4, 
prepared by heating cobalt carbonate. Ni304, prepared 
by heating nickelo-nickelic hydrate to 240° C, is hygro- 
scopic, and absorbs about 7^^ per cent of water from the 
air at 30° C, which is completely lost at 110° C, show- 
ing that no hydrate is formed under these conditions. 

The study of the adion of fused sodium dioxide on 
the metals will be continued here, and it is hoped that 
some more data can be contributed soon. — yournal of the 
American Chemical Society, xviii., OAober, 1896. 



66 



Aluminum Analysis. 



OHBMicAL News, 
Feb. 5, i8q7. 



ALUMINUM ANALYSIS.* 

By JAMES OTIS HANDY. 
(Continued from p. 56). 



Determination of Sodium in Aluminum. 
One grm. of drillings is dissolved in a porcelain evapo- 
rating dish in 50 c.c. of 1*3 sp. gr. nitric acid and sufficient 
hydrochloric acid to effed solution. Boil down until all 
hydrochloric acid has been removed. Rinse the solution 
into a large platinum dish and evaporate to dryness. 
Heat over a good Bunsen burner until nitric oxide fumes 
cease to be evolved. Grind the residue finely. Mix it 
by grinding with i grm. of chemically pure ammonium 
chloride and 8 grms. of chemically pure calcium carbonate. 
Heat the mixture in a large covered platinum crucible. 
For the first fifteen minutes have a Bunsen burner flame 
just touching the bottom of the crucible, and for the next 
forty-five minutes have the whole crucible heated bright 
red by a full Bunsen burner flame. Cool, and treat the 
residue with hot distilled water until it becomes just 
friable under pressure. Avoid adding an excess of water 
beyond that necessary to make the sintered mass just 
friable. Grind it in a Wedgwood mortar, and rinse out 
with hot distilled water. Filter, rejedling the well-washed 
residue, and treat the filtrate at the room temperature 
with saturated ammonium carbonate solution in slight 
excess. Stir very thoroughly. The precipitated calcium 
carbonate is at first flocculent, but on standing for about 
ten minutes it becomes crystalline. Filter into a platinum 
dish ; rejedt the residue, and evaporate the solution on 
the water-bath to dryness. Heat carefully to dull redness 
to expel ammonium salts. Dissolve the residue in a little 
water, and add a few drops of ammonium carbonate solu- 
tion. If this produces a precipitate, add sufficient ammo- 
nium carbonate solution to precipitate all of the remaining 
lime. Stir well, wait ten minutes, filter, evaporate to 
dryness, heat to dull redness, and weigh sodium chloride. 
Dedudt any sodium chloride found in a blank determina- 
tion, using acids, &c., as above, and finally 8 grms. of 
calcium carbonate and i grm. of ammonium chloride. 

NaCl X 0'393i6 = Na. 

Care should be taken when heating up the residue of 
sodium chloride, &c., after evaporating on the water-bath. 
If the platinum dish and contents are heated for a few 
minutes on sheet asbestos on the hot plate before placing 
over the lamp, spattering may be avoided. Sodium is 
generally absent from aluminum, but it has been found 
in amounts as high as 0*20 per cent, and is considered a 
cause of the cccasional deterioration of the metal in 
water. 

Determination of Carbon in Aluminum. {Moissan^s 

Method Modified). 
Triturate 2 grms. of drillings in a Wedgwood mortar 
with 10 to 15 grms. of mercuric chloride, powdered and 
dissolved, or partly dissolved, in about 15 c.c. of water, 
Readion takes place rapidly, and a heavy grey residue is 
left. Persistent trituration removes the last particles of 
metallic aluminum. Evaporate on the water-bath to 
dryness. The dry residue is heated in a current of pure 
hydrogen to expel mercuric compounds. The remaining 
material is then placed in a boat in a combustion-tube 
and burned off as in carbon determination in steel. The 
carbon dioxide is caught as barium carbonate, and the 
excess of barium hydroxide determined by means of 
standard acid. We are working on a more generally 
applicable method for carbon in alummum. 

Determination of Nitrogen in Aluminum. 
Aluminum, when overheated in re-melting, is believed 
to have the property of combining with nitrogen. The 
metal becomes weaker. Moissan's method for deter- 

* Fiom the Journal of the American Chemical Society, Sept., 1896. 



mining nitrogen in aluminum may be found in Complex 
Rendus, cxix., 12. Nitrogen thus absorbed would un- 
doubtedly exist as nitride of aluminum, and solution of 
sodium hydroxide with subsequent distillation would seem 
to be the best method of procedure. We are working up 
this method. 

Determination 0} Aluminum in Metallic Aluminum. 

Dissolve I grm. of metal in 30 c.c. of 33 per cent 
hydrochloric acid in a porcelain dish and evaporate 
cautiously to complete dryness. Re-dissolve, by boiling 
with 10 c.c. of concentrated hydrochloric acid and 75 c.c. 
of water. Wash into a 12-ounce beaker ; dilute to 250 
c.c, and pass hydrogen sulphide until saturated. Filter 
into a beaker and boil off hydrogen sulphide. Oxidise by 
adding i c.c. of concentrated nitric acid and continuing 
to boil for ten minutes. Cool, and make the solution up 
to 500 c.c. Remove 50 c.c. of the solution, and, having 
diluted to 250 c.c. and heated to boiling, add ammonium 
hydroxide in slight excess and boil well for twenty 
minutes. Let settle; filter, and wash thoroughly with 
hot water. It is necessary to wash the precipitate off 
from the filter, break it up, and wash it back again. 
Finally burn off in a thin-walled platinum crucible, 
igniting most intensely, and weighing the instant the 
crucible and contents are cool. We have found that 
alumina is one of the most difficult oxides to dehydrate 
completely, and when dehydrated it absorbs atmospheric 
moisture even more rapidly than calcium oxide does. 
Moissan prefers to precipitate aluminum by ammonium 
sulphide. Having prepared a solution in hydrochloric 
acid, he takes an amount equal to 0*15 grm. of aluminum, 
neutralises it in the cold with ammonia, and precipitates 
it by ammonium sulphide which has been recently pre- 
pared. He then digests for one hour, filters, washes 
with hot water, ignites, and weighs. 

Analysis of Alloys of Aluminum with Smaller Amounts 
of other Metals. 

Copper Alloys. — Three to thirty per cent copper, and no 
zinc or nickel. 

Dissolve i grm. or i grm. in 15 c.c, of 33 per cent 
sodium hydroxide solution in an Erlenmeyer flask of 
12-ounce capacity. If the flask is covered and set in a 
warm place, solution is complete in a few minutes, even 
if the drillings are quite coarse. Dilute to 30 c.c. with 
hot water, and filter through a coarse lintless filter-paper 
(Whitall, Tatum, and Co.'s 5-inch). Wash well with hot 
water. Dissolve residue, after washing it off the filter- 
paper into a 12-ounce beaker, by warming with 5 c.c. of 
concentrated nitric acid. Cool, add saturated commercial 
sodium carbonate solution until re-solution occurs. Titrate 
with standard potassium cyanide solution to the disap- 
pearance of the blue colour. Standardise the cyanide for 
about the same amount of copper. 

For commercial reasons 20 per cent alloys are made in 
the reduction pots, and these alloys are subsequently used 
for making copper alloys of low percentage. 

Determination of Nickel in Aluminum Alloys. 

The 3 per cent nickel alloy is now used. The addition 
of 3 per cent of nickel increases the tensile strength of 
aluminum by several thousand pounds per square inch. 

One grm. of drillings is dissolved in 15 c.c. of 33 per 
cent sodium hydroxide solution in a 12-ounce Erlenmeyer 
flask. Dilute to 50 c.c, and filter through a 5-inch lint- 
less paper, washing the residue thoroughly with hot water. 
Rinse the residue back into the ilask, and add 3 to 5 c.c. 
of concentrated nitric acid, and a drop of concentrated 
hydrochloric acid. Boil, and when dissolved cool, and 
make up to 250 c.c. In 100 c.c. determine the copper by 
neutralising with ammonia, adding 2 c.c. of concentrated 
hydrochloric acid, warming, and passing hydrogen sul- 
phide. Filter and wash with ammonium sulphide. Burn 
it off carefully in a porcelain crucible, and, having 
weighed, dissolve in 5 c.c. of concentrated nitric acid. 



OHSyiCAL NbW8,I 

Feb. 5, 1897. I 



A luminum A nalysis* 



67 



Then dilute to 20 c.c, add excess of sodium carbonate 
solution, and titrate with standard potassium cyanide. 
Boil the filtrate from the cupric sulphide, oxidise with 
I c.c. of nitric acid, and precipitate with ammonium 
hydroxide. Do not boil, but digest for a few minutes 
just below the boiling-point. Filter, wash, re-dissolve in 
hot 15 per cent nitric acid wash. Dilute to 150 c.c, and 
again precipitate with excess of ammonium hydroxide, 
being careful to avoid boiling or prolonged digestion. 
Filter and wash. Burn off and weigh ferric oxide, &c. 
In a second 100 c.c. of the main solution, precipitate 
nickel hydroxide, cupric oxide, ferric hydroxide, &c., by 
33 per cent chemically pure sodium hydroxide solution, 
added in slight excess to the boiling solution. Boil for 
fifteen minutes, filter, and wash most thoroughly with 
hot water. Burn off and weigh nickel oxide, cupric 
oxide, and ferric oxide. Deducft cupric oxide and ferric 
oxide already found. Calculate nickel oxide to metallic 
nickel. 

Analysis of Aluminum-Manganese Alloys. 
Determination of Manganese. — Place i grm. of drillings 
in a i2-ounce beaker. Add 30 c.c. of 33 per cent hydro- 
chloric acid (one part of concentrated hydrochloric acid 
to two parts of water). When dissolved add 25 c.c. of 
nitric acid (1*42), and boil down to 10 c.c. Add 50 c.c. of 
colourless nitric acid (i'42), and boil. Precipitate the 
manganese with powdered potassium chlorate, added 
cautiously, and proceed as described under manganese in 
steel by Williams's method (Blair's " Chemical Analysis 
of Iron "). 

Analysis of Chromium-Aluminum Alloy. 
Determination of Chromium. — Dissolve i grm. in a 
i2-ounce beaker in 30 c.c. of 33 per cent hydrochloric 
acid, and when dissolved add 50 c.c. of sulphuric acid 
(i'84), and evaporate carefully until fumes of sulphur 
trioxide escape. Cool, add 60 c.c. of water, and boil. 
After five minutes, if all aluminum sulphate has been 
dissolved, add powdered potassium permanganate until 
the solution has a distind pink colour. Boil until the 
excess of potassium permanganate is decomposed. Filter 
through washed asbestos, and determine the chromium 
in the filtrate as in chrome steel (Galbraith's method. 
See Blair's •' Chemical Analysis of Iron"). 

Analysis of Tungsten-Aluminum Alloy. 
Determination oj Tuw^sfeM.— Dissolve i grm. in 33 per 
cent hydrochloric acid in a 4J-inch evaporating dish. Add 
30 c.c. of nitric acid (i'42), and evaporate to dryness. 
Re-dissolve in 30 c.c. of hydrochloric acid (i"2o), dilute 
to about go c.c, and boil for two hours. Filter and wash 
thoroughly. Burn off and weigh Si -|- Si02-f-W03 -f- cru- 
cible. Treat with 3 drops of 25 per cent sulphuric acid 
and about 2 c.c. of hydrochloric acid. Evaporate care- 
fully over an Argand burner, re-ignite, and weigh crucible 
and silicon and tungstic oxide. Fuse with i grm. of 
sodium carbonate, cool, place in dish, and add 15 c.c. of 
water and 20 c.c. of 25 per cent sulphuric acid, remove 
crucible, and evaporate until white fumes escape. Cool, 
re-dissolve in about 50 c.c. of water. Filter, wash, ignite, 
and weigh silica (from silicon), tungstic oxide, and cru- 
cible. Treat with sulphuric acid and hydrofluoric acid, 
evaporate, ignite, and re-weigh. Loss equals silica. 
Calculate to silicon, and add to the weight of silica lost 
by treatment of first insoluble residue. Dedudt this sum 
from the weight of silicon, silica, and tungstic oxide first 
found, and the remainder equals tungstic oxide. Calcu- 
late to tungsten. 

Analysis of Aluminum-Titanium Alloy. 
Determination of Titanium. — Two grms. of the alloy 
in a i2-ounce Erienmeyer flask are dissolved by addition 
of 50 c.c of 10 per cent potash solution. Dilute with 
distilled water to about 125 c.c, boil up, and filter as 
quickly as possible. Wash ten times with boiling water. 



Burn off the residue in a porcelain crucible, crush it in a 
Wedgwood mortar, fuse in a large platinum crucible with 
10 grms. of potassium bisulphate. Condudt the fusion 
exaAly as follows : — Choose a good Bunsen burner, and 
protedl it from draught by a sheet-iron chimney ; make 
the flame i^ inches long, and place the triangle carrying 
the upright crucible just at the point of the flame. In- 
crease the heat gradually until in ten minutes the lower 
fourth of the crucible is red hot. Allow it to remain at 
this temperature ten minutes, moving the lid slightly to 
one side every two minutes, and giving the crucible (held 
firmly in the tongs) a gentle rotating movement, then turn 
up the light until the flame reaches the top of the crucible 
and envelopes it. Five minutes of this treatment melts 
down any potassium bisulphate, &c, which have risen on 
the sides. The flame is lowered and the lower fourth heated 
for ten minutes longer. Cool, dissolve in about 200 c.c 
of water ; filter, rejedling the residue, if ignition and 
treatment with hydrofluoric acid show it to be only 
silica. If it contains anything more, fuse with 4 grms. of 
potassium bisulphate again. The filtrate contains all the 
titanic oxide and the ferric oxide. Add ammonia until a 
slight permanent precipitate is formed, then add dilute 
sulphuric acid from a pipette or burette until this precipi- 
tate just re-dissolves. Finally add i c.c. more of 25 per 
cent sulphuric acid, and dilute to 300 c.c. If the solution 
is high in iron (which will be indicated by its distindl 
yellow colour) sulphur dioxide gas must be run into it 
until it is decolourised and smells strongly of sulphur 
dioxide; but if the solution is nearly colourless, indicating 
a low percentage of iron, only sulphur dioxide water 
need be added for the redudtion. Boil well for one hour, 
adding water saturated with sulphur dioxide occasionally. 
Filter off the titanic oxide through double filters, and 
wash well with hot water. Burn off and weigh as titanic 
oxide. If the precipitate is yellow, indicating the pre- 
sence of iron, it may be fused with i grm. of potassium 
bisulphate, the fusion dissolved in 10 c.c. of dilute sul- 
phuric acid, and the iron determined in this solution by 
reducing with i grm. of zinc, and titrating with perman- 
ganate. This is not often necessary. Calculate titanic 
oxide to titanium. TiOj X o-6 = Ti. 

Determination of Zinc in Zinc-Aluminum Alloys. First 
Method. 
Dissolve I grm. in 30 c.c of 33 per cent hydrochloric 
acid in a i2-ounce beaker. Dilute to 200 c.c, and heat 
nearly to boiling. Pass hydrogen sulphide till all copper 
is precipitated. Filter and boil off hydrogen sulphide, 
oxidise with i c.c nitric acid by boiling ten minutes. 
Add sodium hydroxide solution until neutral, then make 
barely acid with hydrochloric acid, and stir until the 
aluminum hydroxide all dissolves. Add 10 grms. of 
sodium acetate and 500 c.c. of water, boil up, and filter 
at once. Dissolve the washed precipitate in hydrochloric 
acid, and repeat the acetate separation. Heat the 
united filtrates to boiling and pass hydrogen sniphide. 
Filter off the zinc sulphide on double filters, wash 
thoroughly with hot water. Burn off in a porcelain cru- 
cible, and weigh zinc oxide. Calculate to zinc This 
method may be used when only a small quantity of the 
sample is available; but when this is not the case, it is 
better to use the method given below. 

Determination of Zinc in Zinc-Aluminum Alloy. Second 
Method. 
Dissolve I grm. of drillings in 33 per cent sodium 
hydroxide solution in a 12-ounce Erienmeyer flask. Filter 
as soon as dissolved through a 4-inch lintless filter-paper. 
Wash thoroughly with hot water. Rinse the residue of 
zinc, iron, copper, silicon, &c., back into the flask. This 
may require 25 c.c. of water. Add 5 c.c. of hydrochloric 
acid and boil. Dilute to 150 c.c. with hot water and pass 
hydrogen sulphide. Filter and boil off hydrogen sulphide, 
re-oxidise by adding i c.c. nitric acid and boiling ten 
minutes. Add sodium hydroxide till neutral, then add 



68 



Constitution of Benzene, 



{Chemical NkWb, 
Feb. 5, 1897. 



dilute hydrochloric acid till just acid, and then 10 gims, 
of sodium acetate, and 300 c.c. of boiling water, and boil 
for five minutes. Wash well. If the precipitate is small 
re-solution and re-precipitation are not necessary. Pass 
hydrogen sulphide through the filtrate. Filter off zinc 
sulphide through double filters. Wash well. Ignite in a 
porcelain crucible, heating finally over the blast to zinc 
oxide. ZnOxo'8o32 = Zn. 

Analysis of Aluminum Solders. 
Determination 0/ Tin, Phosphorus, and Z««c.— Alumi- 
num solders generally contain phosphor-tin and zinc. As 
presented for analysis they usually consist of a soldered 
joint, from which the solder must be scraped and analysed. 
The analysis, therefore, involves a separation of the 
elements aluminum, zinc, tin, and phosphorus. It is a 
difficult matter to determine whether aluminum was a 
constituent of the solder when only a soldered joint is 
available for examination. It is best to dissolve all 
adhering aluminum from the pieces chosen for analysis by 
treatment with 33 per cent sodium hydroxide solution, 
after which the residue is filtered off, dried, and weighed 
out for analysis. Dissolve or decompose three-tenths to 
five-tenths grm. in a twelve-ounce beaker by means of 
20 c.c. of nitric acid (i'42). If necessary, 5 c.c. of hydro- 
chloric acid (i'2) may be used to effeft complete decom- 
position. Evaporate to complete dryness on a hot plate. 
Cool, add 25 c.c. of nitric acid (i'i3), and boil thoroughly. 
Filter. The residue contains all of the tin, most of the 
phosphorus, and possibly some zinc. Burn it off in a 
porcelain crucible, and, after pulverising the residue in an 
agate mortar, mix it with 2 grms. of sodium carbonate 
and 2 grms. of sulphur, fuse it in a covered porcelain 
crucible over a Bunsen burner for about half-an-hour. 
Give it three minutes of gentle blast flame at the last. 
Cool, boil out with 150 c.c. of water in a twelve ounce 
covered beaker. Filter and wash. Extracft any possible 
zinc sulphide, &c., from the residue by dissolving in nitric 
acid, boiling off hydrogen sulphide, and adding this to 
the first filtrate obtained after evaporating to dryness with 
nitric acid. The sodium sulphide solution contains the 
tin and phosphorus. Add it to hydrochloric acid until 
just acid. Warm slightly and pass hydrogen sulphide. 
Filter off stannous sulphide and wash thoroughly with hot 
water. Burn off in a porcelain crucible and weigh stannic 
oxide. Calculate to metallic tin. rhe filtrate from the 
stannous sulphide is boiled to expel hydrogen sulphide, 
and then oxidised by adding 2 c.c. of nitric acid and 
boiling for fifteen minutes more. Filter off any sulphur 
which separates, and in this filtrate, which should amount 
to only about 100 c.c, precipitate the phosphorus by 
adding pure sodium hydroxide solution till alkaline, then 
nitric acid till distindly acid, heating to 85° C, and 
adding 50 c.c. of filtered molybdate solution. Stir or 
shake well for five minutes, filter on a weighed filter 
paper, and after washing with one per cent nitric acid 
wash, dry at 100° C, and weigh. Yellow precipitate 
multiplied by o"oi63 equals phosphorus. The nitric acid 
solution obtained after evaporating the first solution to 
dryness, &c., is now neutralised with sodium hydroxide 
solution, and then made just acid with hydrochloric acid. 
Ten grms. of sodium acetate are now added, and 300 c.c. 
of water (hot). Boil up for five minutes, then filter and 
wash. If the precipitate is of considerable size, it is pro- 
bable that aluminum was a constituent of the solder. 
Re-dissolve it in a little hydrochloric acid, neutralise, 
acidify, and make a basic acetate separation as before. 
Precipitate the zinc in the acetate solutions by hydrogen 
sulphide. Filter, wash, ignite in a porcelain crucible, and 
weigh as zinc oxide. Calculate to metallic zinc. Dis- 
solve the precipitate of aluminum acetate in hydrochloric 
acid, dilute to 250 c.c, and precipitate with ammonia. 
After filtering, washing, igniting, and weighing as 
alumina, calculate to metallic aluminum. Solders con- 
taining lead are sometimes met with. In such cases, 
evaporate the nitric acid filtrate from the metastannic 



acid to small bulk, add 25 c.c. of 25 per cent sulphuric 
acid, and evaporate until white fumes escape. Cool, add 
100 c.c. of water, stir, an d let stand for an hour in a warm 
place. Filter and wash with water containing 5 per cent 
sulphuric acid. Burn off in a porcelain crucible at a low 
temperature. Re oxidise any reduced lead oxide, and 
restore its sulphur trioxide by adding a few drops of nitric 
acid and sulphuric acid and evaporating. Finally weigh 
lead sulphate. Calculate to metallic lead. Zinc is deter- 
mined in the lead sulphate filtrate. 

Analysis 0/ Alumina.' 
Alumina is made from bauxite or cryolite. It is usually 
purchased in the hydrated form. 

(To be continued). 



PROCEEDINGS OF SOCIETIES. 



EDINBURGH 



UNIVERSITY 
SOCIETY. 



CHEMICAL 



At a meeting of the Edinburgh University Chemical 
Society on the nth January, a paper was read by Dr. 
Macdonald on the" Constitution of Benzene." 

The different formulas from time to time proposed for 
benzene were discussed and criticised. It was pointed 
out that for the study of all ordinary benzene derivatives, 
Kekule's hexagonal formula had proved the most service- 
able. The identity of 3- and 5-methylpyrazole is much 
akin to the benzene tautomerism, and points more clearly 
to re-arrangement of single and double bonds such as 
proposed in Kekule's oscillation hypothesis. This hypo- 
thesis is difficult to accept in detail, but for a working 
hypothesis it is sufficient to assume that in certain 
peculiar conditions of ring symmetry double linkings are 
not fixed. The disturbing agent might be found in the 
intra-molecular energy. Assuming this to take the form 
of energy of motion round the ring, the single and double 
bonds would then repiesent something like the phases pf 
a wave motion. 

At the Fourth Ordinary Meeting, held on Monday, Jan. 
25th, 1897 (^^'■- Macdonald in the chair), Dr. Dobbin 
read a paper on the subjed — " Who Introduced the Use 
of the Balance into Chemistry ? " 

After quoting a variety of statements from current text- 
books, which more or less emphatically attributed to 
Lavoisier the discovery of the law of the conservation of 
matter, and the first employment of the balance in investi- 
gating theoretical questions in chemistry, the author of 
the paper remarked upon the startling character of these 
statements to any person who had read Black's research 
on " Magnesia Alba," and quoted a few passages from 
Black in support of the statement that every step in his 
investigation has been made good by appeal to diredt quan- 
titative experiments. He next quoted a passage from *' La 
Revolution Caimique," showing that Berthelot was well 
aware of the fa<5t that these views regarding Lavoisier 
were entirely at variance with the true state of matters. 

Dr. Dobbin then went on to mention that, so far as he 
was aware, the well known and often quoted experiment 
of van Helmont upon the supposed formation, from water 
only, of 164 pounds weight of the substance of a willow 
tree — the weight of the earth in which this willow grew 
having varied only by about two ounces in five years — 
was the earliest attempt to determine the accuracy of a 
view concerning a matter of scientific fadl by appeal to 
quantitative experiment. It was further pointed out that 
Boyle made very frequent use of the quantitative method 
of investigation in dealing with the most diverse subjects, 
and that his inspiration in this direi5tion was very probably 
derived from van Helmont. 



UriKMICAL NBWA, 1 

Feb. 5, 1897. / 



Manufacture and Properties of Structural Steel, 



69 



The author concluded his paper by pointing out, with 
regard to Lavoisier's examination of the alleged con- 
version of water into earth, that every essential point in 
the investigation, and in the mode of carrying it out, was 
to be found discussed or suggested in the works of Boyle, 
of which we know that Lavoisier was an attentive 
student. So far as he had been able to ascertain, atten- 
tion had not previously been called to this fadt by the 
historians of chemistry. 



NOTICES Of BOOKS. 



The Manufacture and Properties of Structural Steel, 

By Harry Hume Campbell, S.B. New York and 

London : The Scientific Publishing Co. 8vo., pp. 397. 

1896. 
If we were called upon to classify this valuable work we 
should feel at a loss. A chemical treatise it certainly is 
not, seeing that the metal which it discusses is charadler- 
ised not by its chemical composition, qualitative or quan- 
titative, and is hence named •' structural steel." Chemical 
considerations are certainly not overlooked, but they play 
here a relatively less weighty part than they do, eg., in 
tissue-printing or in alkali-making. If we bear in mind 
that steel and iron works are in the hands of engineers, 
and that the authorities here quoted are the proceedings 
of societies for civil and mechanical engineering we must 
place this work under the category of " engineering." 

The author in his first chapter brings forward the 
" errancy " of scientific records — a painful subjedt under 
a strange name. Errors are shown in Howe's "Metal- 
lurgy of Steel." 

These variations in the results of experiments are due 
to the accumulation of petty errors. It is of some con- 
solation to find that the variations here cited are not in 
chemical composition, but in physical properties, such as 
ultimate strength, elastic limit, percentage of elongation, 
redudion of area, and percentage of elastic ratio. But 
variations in chemical composition are also quoted. The 
different methods of determining carbon vary to an extent 
unexpected as unsatisfaftory. 

The author remarks — as it might be fairly expedted — 
that the comparison of miscellaneous records is perfedlly 
useless and misleading. " Even the results of two 
different well-condudted laboratories may not be trustingly 
placed together. This may be done if the two works in 
question exchange samples and find that both obtain 
similar results from the same metals, but under no other 
circumstances is the comparison valid." 

In the determination of phosphorus similar but more 
important errors are committed. 

The authorconcludes this chapter with thepithy didtum : 
" The making of steel was once a trick; it was then an 
art ; it is now a business." 

Chapter IV. leans to the definition of steel, a task 
which though apparently simple has never yet been 
accomplished to the satisfadlion of all concerned. " A 
true formula," says an author, " must apply not only to 
all the metals commonly designated by the term, but to 
all compounds which ever have been or ever will be 
worthy of the name, including the special alloys made by 
the use of chromium, tungsten, nickel, and other elements 
introduced to give peculiar qualities for special purposes." 

After criticising various proposed definitions the author 
gives the following standards as embodying current usage 
in America, and become universal also in Britain and in 
France. In other lands the authority of famous names, 
backed by conservatism (word wrongly used!) govern- 
mental prerogative, has fixed for the present in metal- 
lurgical literature a list of terms which I have tried to 
show is not only difficult but fundamentally false. 

The author understands therefore by the term wrought 



iron the produd of the puddling furnace or the sinking 
fire. On the other hand, " by the tcr n steel is meant the 
produce of the cementation process, or the malleable 
compounds of iron made in the crucible, the converter, or 
the open-hearth furnace." 

In subsequent chapters we have accounts of the acid 
and the basic Bessemer processes, as also the open-hearth 
process in its acid and basic modifications. 

In Chapter XVII. follows an investigation ofthe influence 
of certain elements on the physical properties of steel, the 
pre-eminence in injurious effedls being ascribed to phos- 
phorus. " Safety increases as phosphorus decreases," and 
the engineer may calculate just how much he is willing 
to pay for greater protedtion from accident. 

A relatively high proportion of copper has in certain 
experiments given a slightly higher elastic ratio and a 
better elongation and redudlion of area. These results 
are scarcely to be viewed as conclusive. 

Aluminium has little effedt upon tensile strength, while 
it does not injure the dudtility in proportions under 2 per 
cent. 



Notes on the Qualitative Analyns arranged for the Use of 
Studettts of the Rensselaer Polytechnic Institute. By W. 
P. Mason, Professor of Chemistry. Third Edition. 
Easton, Pennsylvania, Chemical Publishing Co. 1896. 
i2mo., pp. 56. 

In the Preface to this little book we find the admission 
that " the market is unquestionably much overstocked 
with books upon this subjedl," and the author puts for- 
ward as his only excuse that it meets the requirements 
of his own classes. He further expresses the opinion 
that, were it not for the " expense of printing, every 
teacher of chemistry would use a text-book made by 
himself with either pen or scissors." Sad, indeed, if true 1 
He hopes that those who use the matter here given may 
be led so to think for themselves as to " create a desire 
to know rather than an anxiety to pass." This is a very 
laudable aspiration, but we doubt if there is anything 
calculated to create this desire in this book rather than 
in not a few others. In the recognition of certain ele- 
ments the author makes use of the spedtroscope and of 
blowpipe readlions. 



An Introduction to the Study of Chemistry. By W. H. 
Perkin, Jun., Ph.D., F.R.S., Professor of Organic 
Chemistry in the Owens College, Manchester; and 
Bevan Lean, D.Sc, B.A., Assistant Ledlurer and 
Demonstrator, and late Berkely Fellow of the Owens 
College, Manchester. London: Macmillan and Co., 
Ltd. New York : The Macmillan Co. 1896. Pp. 399. 

This is a gratifying book. The student is trained to re- 
discover, or, as the case may be, to re-demonstrate for 
himself, the cardinal fadtor and laws of chemical^science. 
Hence, instead of — as is too generally the case — closing 
the book with the sad refledlion that the contents, how 
true soever, are a mere rechauffee of what has been many 
times said before, we are in a position to congratulate the 
authors and still more their pupils and readers. They 
are reminded in the Preface, according to a quotation 
from Prof. H. A. Miers, that " the order in which pro- 
blems have presented themselves to successive genera- 
tions is the order in which they may be most naturally 
presented to the individual." 

In carrying out this plan the author gives an abstradl 
of the birth of chemistry drawn fron the invaluable work 
of Berthelot. The passages cited fully support the 
maxim that conclusions must be tested by experiment 
and by measurement. Virgil's strange recipe for gene- 
rating a swarm of bees from the putrid carcase of a 
bullock may be traced to the inability of the classical 
world to distinguish bees from certain carrion-hunting 
Diptera. 



70 



Chemical Notices from Foreign Sources. 



Chemical News, 
Feb. 5, 1807. 



In the chapter on the metric system the authors do not 
overlook its occasional inconveniences, e.g., its unsuit- 
ableness to retail trade. They do not mention the 
pedantic refusal of French and other instrument 
makers to admit of any weights except the multiples 
and submultiples of 10. Had they been willing, instead 
of the French arrangement of 5, 5, 2. 2, i, to adopt the 
English scale, 6, 3, 2, i, they would have found the 
metric system gain in popularity. 

We are most favourably impressed with Messrs. 
Perkin and Lean's book, and hope that it may be widely 
appreciated. 

The Progress of Medical Chemistry, comprising its Appli- 
cation to Physiology, Pathology, and the Practice of 
Medicine. By J. L. W. Thudichum, M.D., F.R.C.S.L. 
London: Baiiliere, Tindall, and Cox. i8g6. Pp.212. 

We have here a handy book, which will prove of great 
value to the earnest student of animal chemistry, in per- 
haps its most complicated region. The charader of the 
work is decidedly controversial, and it possesses a not un- 
pleasant acidulous flavour. 

The controversy is mainly direded against the shade of 
the late Professor F. Hoppe-Seyler, Briicke, E. Salkowsky, 
Kossel, Freitag, &c. We must not, however, suppose 
that Dr. Thudichum's hand and pen are raised against 
all his contemporaries engaged in the same class of re- 
searches. 

The author commences his work by comments on the 
" Rise of Specialism, Limited." In a succeeding paragraph 
he enlarges on the reign of the phagocyte, and the asto- 
nishing feats of this creature of the baderiological 
imagination, "among which none was more surprising 
than that by which it put all chemistry to shame — namely, 
chemotaxis." 

We have an elaborate discussion of the protagon 
question, which we hope after all its changing phases 
may now be considered as definitively settled. Dr. Thu- 
dichum tells us that the effedt of the analytical operations 
of Kossel and Freytag is entirely retrograde, as they 
" carelessly repeat indecisive data, ignore fadts which 
have been proved for many years, iterate refuted errors, 
try to displace proved fads, substitute erroneous names 
and dates for true ones, and in the only part of their ope- 
ration which might have furnished something original 
and new fail in a manner which is the necessary result 
of disregard for the accepted principles of scientific 
research." 

Towards the end of the book we have a very interesting 
chapter on *' Shady Side of Biological Science," otherwise 
the ghosts of spurious researches. Following the ex- 
ample of Babbage, he divides spurious researches into 
four groups — forgeries, hoaxes, cooked and trimmed 
results. 

In addition come the blundenngs, made not necessarily 
in bad faith. 

We may thank Dr. Thudichum for some innovations in 
nomenclature which are decided improvements. For 
alcohols in its generic sense he would say " cohols." 
•' Quantation " is a convenient abbreviation for quantita- 
tive determination. 



CORRESPONDENCE. 



Dimorphism of the Succinates of the Camphols 
-{-a and -a; Isomorphism of the Succinates of the 
Camphols +aand —a, and of the Succinates of the 
Isocamphols -i-j8 and -/3.— J. Minguin.— As the crys- 
talline form of the succinates approximates decisively to 
that of borneol and that of camphor, it should seem that 
a transformation of CO into the CHOR of camphor does 
not sensibly affed the crystalline form, whilst a trans- 
formation effeded in CHj makes itself more ieh.—Comptes 
Rendus, cxxiv., No. 2. 



ON THE RELATION OF THE SPECIFIC 

ROTATORY AND CUPRIC REDUCING POWERS 

OF THE PRODUCTS OF STARCH 

HYDROLYSIS BY DIATASE. 

To the Editor of the Chemical News. 
Sir, — The paper by Messrs. Brown, Morris, and Millar, 
read before the Chemical Society on December 17th, 
i8g6, and subsequently abstraded and appearing in the 
Chemical News, Ixxiv., 43, confirms my own experience 
in starch estimation in various produds by the O'SuUivan 
process. I have found that, without exception, there is 
a constant relation between the cupric reducing power 
and the specific rotatory power, and am, therefore, glad 
to see a confirmation of my own work by such eminent 
chemists as the authors of the above paper. — I am, &c., 

J. Arthur Wilson. 

Newchurcb, Rossendale, 
Jan. 27, 1897. 



CHEMICAL NOTICES FROM FOREIGN 
SOURCES. 

Note. — All degrees of temperature are Centigrade unices otherwise 

expressed. 

Zeitschrift fur Analytische Chemie. 
Vol. xxxvi.. Part i. 

A Contribution to the Chemistry of Animal Fats. 
— Carl Amthor and Julius Zinc. — An elaborate paper, 
not admitting of abstradion. 

Determination of Formaldehyd. — Dr. G. Romijn. — 
For the examination of pure solutions of formaldehyd 
the iodometric method is to be preferred, on account of 
its great accuracy and convenient execution. The me- 
thods of Brochet and Cambier and the potassium cyanide 
method may also be recommended. But if the presence 
of other aldehyds is to be feared the potassium cyanide 
method is suitable, and, along with the iodometric 
method, will in many cases permit of the entire analysis 
of the mixture. Legler's method will never bear a com- 
parisun with the other three methods. 

Behaviour of the Shellac Acids in the Separation 
of Fatty Acids and Resin Acids, according to Glad- 
ding and Twitchell. — F. Ulzer and Rudolf Defris. — 
It appears that samples are sold under the name of 
shellac which consist of a mixture of shellac and ordi- 
nary colophonium. 

Determination of Thoria in Thorin. — E. Hintz and 
H. Weber. — This memoir will be inserted in full. 

Determination of Fatty Matter in Miik. — H. Frese- 
nius. — The author evaporates the sample over purified 
quartz-sand, and extrads the dry residue with ether in a 
suitable apparatus. After distilling off the ether, the 
residual fat is dried for one hour in a weighing-glass at 
100°, and weighed. 

A Simple and Universally Applicable Method for 
Determining the Water in Silicates. — P. Jannasch and 
P. Weingaten (^Zeit. Anorg. Chem.). — This paper requires 
the accompanying illustration. 

A Technical Pyrometer. — W. C. Heraus and Keiser 
and Schmidt. — Tnis instrument depends on the same prin- 
ciple as that of Le Chatelier, and is described in the 
Zeit. fur Instrumentenkunde. 

Determination of Arsenic— R. Engel and J. Bernard. 
— From the Comptes Rendus. 



Ubbmical NBWS, I 
Feb. 5. 1897. I 



Chemical Notices from Foreign Sources, 



71 



Produ<5tion of Chlorine for Laboratory Purposes. 
— F. A. Gooch and D. A. Kreider {Ztit. fur Anorg. 
C hemic). 

Analysis of Purified Zinc. — F. Mylius and O. 
Fromm {Zeit. fur Anorg. Chemie).— This memoir will be 
inserted in full. 

Quantitative Determination and Separation of 
Copper. — F. Mawrow and W. Muttmann {Zeit. fur 
Anorg. Chemie).— This memoir will be inserted in extenso. 
Detection of Formaldehyd. — G. Romijn [Nederland 
Tijdschrift voor Pharm. Chem. en Toxicologie). — The 
author is of opinion that formaldehyd may best be recog- 
nised by conversion into hexamethylamin by means of 
ammonia. At ordinary temperatures this transformation 
is efTeAed in eighteen to twenty hours. At higher tem- 
peratures the conversion is very rapid. The addition of 
lormaldehyd to ammoniacal liquids as a disinfectant is 
therefore of little value. Romijn gives a number of re- 
actions for the identification of hexamethylamin. 

Determination of Nitrogen in presence of Ni- 
trates. — H. C. Sherman. — From the jfournal of the 
American Chemical Society. 

Execution of the Gravimetric Determination o 
reducing Sugar by means of Fehling's Solution. — 
Abstracts are here given of recent papers by Nihoul, 
Griinhut, Killing, Piager, Farnsteiner, and Hefelmann. 

Occurrence and Determination of Copper in 
Organic Substances, especially in Foods. — From the 
Archiv Jur Hygiene, Chemiker Zeitung, and Kaiserlich 
Gesundheits amte. 

Normal Constituents of Betrwort which may be 
supposed to be Abnormal. — J. Brand [ZeU.fur Brau- 
wesen and Dingier' s Polyt. Journal, also Berichte, xxvii., 
3115). — Of these substances the principal is maltol, 
C6H6O3. It is probably a methyl-pyromeconic acid. 

Examinationof Mace.— E. Spaeth.— The fatof genuine 
mace is yellowish brown, while that of Bombay mace is 
light yellow. 

Volumetric Determination of Lead. — A. C. Becbe. 
From the Chemical News. 

Determination of Dry Matter in Peat. — H. Puchnor 
(Lonw. Versuchstationen). — Not suitable for abridgment. 

Behaviour of Stannous Chloride with Essential 
Oils. — E. Hirschsohn.— The author has previously ob- 
served that the ethereal oil obtained from Gurgun balsam 
by means 01 watery vapour, if boiled with stannous 
chloride, gives a red colour passing into violet and blue. 
He proposes examining a series of ethereal oils by this 
reaction. — (Pharm. Zeitung Rusiland). 

Alkaloidal Siearates and their Therapeutic Appli- 
cation. — F. Zonandi. — The author has examined the 
preparation and properties of the morphin, atropin, and 
cocain stearates. 

Action of Morphine and of Acetanilide upon Mix' 
tures of Ferric Salts and Potassium Ferricyanide. — 
E. Schaer (Archiv der Pharmacie). — This paper is more 
of theoretical than analytical importance. 

Detection and Determination of Sodium Salicyl- 
ate in presence of Icbthyol (jfourn. de Pharmacie). — 
Vissen dries the mixture with fine sand on the water-bath, 
and extracts in the Soxhlet apparatus with anhydrous 
ether. 

Testing the Purity of Apiol. — G. Francois {journal 
de Pharmacie and Pharm. Central-Halle). 

Atomic Weight of Tungsten.— R. Schneider. — The 
mean from all the author's experiments is 184-01. 

Atomic Weight of Helium. — M. A. Langlet (Zeit. 
Anorg. Chemie). — The mol. of helium, like that of argon, 
contains only one atom, and its atomic weight must be 
taken as = 4* 



MISCELLANEOUS. 

Harben Gold Medal. — At a meeting of the Harben 
Nomination Committee held last month in connection 
with the British Institute of Public Health, Professor 
Max von Pettenkofer, Scientific Director of Liebig's Ex- 
tract of Meat Company, was nominated Harben Gold 
Medallist for 1897. '^^^ medal was founded in 1895 by 
Henry Harben, Esq., J. P., for the recognition of eminent 
service to the public health, and one presentation is made 
every year. 

Institute of Chemistry.— January Examinations, 
1897 — Candidates who passed the practical examination 
for the Associateship : — Walter Harry Barlow, Finsbury 
Technical College; Charles Beavis, Ph.D. (Wiirzburg), 
Universities of Bonn and Wiirzburg, and with Dr. Quirin 
Wirtz, F.I.C. (for Fellowship); Cecil Joslin Brooks, King's 
College, London ; Ernest Mostyn Hawkins, Finsbury 
Technical College, London ; Charles J. S. Makin, Royal 
College of Science, London, and the Fresenius Laboratory, 
Wiesbaden; William Moore, Laboratories of the Pharma- 
ceutical Society, University College, London, and with 
Professor John Attfield, F.R.S., F.I.C. ; Sigmund Salomon 
G. Rosenblum, University of Warsaw, Fresenius Labora- 
tory, Wiesbaden, and with Dr. Samuel Rideal, F.I.C. 
Intermediate Examination. — Reginald Arthur Berry, Cam- 
bridge University ; John Alfred Foster, under the late 
Dr. A. Norman Tate, F.I.C , Professor V. B. Lewes, 
F.I.C. ; Robert Dexter Littlefield, University College, 
London, and also with Dr. John Muter, F.I.C, and Mr. 
W. A. H. Naylor, F.I.C. Final Examination for the 
Associateship (In Branch A., Mineral Analysis). — Frank 
Collingridge, B.Sc, (Lond.),'UniverBity College, London 
(passed "Intermediate." July, 1896); William Ranson 
Cooper, M.A., B.Sc, (R.U.I,), Royal University of Ire- 
land, and King's College, London; John Allsopp Walker, 
B.A. (Oxon.), Oxford University. (In Branch E., Analysis 
of Water, Food, and Drugs). — Raymond St. George Ross, 
Owens College, Manchester, and Dresden Polytechnic 
(for Fellowship). Examiners : Professor Percy F. Frank- 
land, F.R.S., F.I.C, and Otto Hehner, Esq., F.I.C. 

City and Guilds of London Institute for the 
Advancement of Technical Education. — The follow- 
ing is the Scheme for the Leathersellers' Company's 
Research Fellowships in Chemistry, founded and De- 
cember, 1896, during the Mastership of Dr. W. H. 
Perkin, F.R.S. :— 

I. — Number and Amount of Fellowships. 

1. The Grant of £1^^ a year offered by the Leather- 
sellers' Company shall be applied in founding one or 
more Fellowships, entitled '• Leathersellers Company's 
Research Fellowships," for the encouragement of Higher 
Research in Chemistry in its relation to Manufactures. 

2. The amount of the grant attached to each Fellow- 
ship shall be determined by the Executive Committee of 
the Institute, regard being had as far as practicable to the 
nature of the Research, the time required to complete it, 
and the merits of the candidate ; subjeCt in all things to 
the approval of the Company. 

II. — Conditions of Eligibility. 

1. Applications for Fellowships shall be made in 
writing, addressed to the Honorary Secretary of the In- 
stitute, at the Head Office, Gresham College, E.C, and 
shall state the name of the proposed research and the 
qualifications of the candidate. 

2. The Fellowships shall be open to natural born British 
subjects, who are — 

a. Students of the Institute who have completed a full 

three years' course of instruction in the Chemical 
Department of the Central Technical College, or 

b. Candidates duly qualified in the methods of Chemi- 

cal Research in its relation to manufactures, with- 
out restriction as to age or place of previous study, 
but preferably to class (a) . 



72 



Meetings for the Week. 



f Chemical News, 
\ Feb 5, 1897. 



III. — Award. 

1. The Fellowships shall be awarded by the Executive 
Committee with the consent of the Company in accord- 
ance with this Scheme, or with such modifications as the 
Company may from time to time approve. 

2. The Executive Committee shall appoint a special 
Committee to receive applications, and seleiSt candidates, 
and to report thereon, and upon the progress of researches ; 
and such Committee shall include the representative or 
representatives for the time being of the Company on the 
Executive Committee. 

3. The Executive Committee shall report to the Com- 
pany the award of each Fellowship, and at the close of 
each session shall report the results or progress of the 
Research or Researches undertaken during the session. 

W.— Tenure. 

1. Every Fellowship shall be tenable for part of a year 
or for one year, and may be renewed for a second or third 
year, but in no case shall be held for a further period. 

2. Holders of Fellowships shall devote their whole time 
to the prosecution of research, unless otherwise sandtioned 
by the Executive Committee, and shall report as required 
on their work. 

3. The Researches shall be carried out at the Central 
Technical College, and the holders of Fellowships shall 
be subjedt to the regulations of the College and the super- 
vision of the Board of Studies. 

4. The Company reserve to themselves the right at any 
time to modify this Scheme, or to withdraw all or any of 
the Fellowships. 

F. A. Abel, Chairman of the Executive Committee. 
John Watney, Honorary Secretary. 



MEETINGS FOR THE WEEK, 



MoNDAV, 8th.— Society of Arts, 8. (Cantor Lectures). " Material 

and Design in Pottery," by Wm. Burton, F.C.S. 
Tuesday, gth. — Royal Institution, 3. " Animal Eledtricity," by 
Prof A. D. Waller. F.R.S. 

Society of Arts, 8. '' Lithography as a Mode of 

Artistic Expression," by George McCuUoch. 
Wednesday, loth.— Society of Arts, 8. " The Chemistry of Tea," 

by David Crole. 
Thursday, nth.— Royal Institution, 3. " The Problems of Arftic 
Geology," by J. W. Gregory, D.Sc, F.R.S. 

Society of Arts, 4.30 (at Imperiallnstitute). "The 

Progress of Science Teaching in India," by 
Prof. J. C. Bose. 

Society of Arts, 8. " The Mechanical ProduAion 

of Cold," by Prof. James A. Ewing, M.A., F.R.S. 
Friday, I2th. — Royal Institution, 9. "Recent Advances in Seis- 
mology," by Professor John Milne, F.R.S., F.G.S. 
Saturday, 13th.— Royal Institution, 9. " The Growth of the 
Mediterranean Route to the East," by Walter 
Frewen Lord. 



Recently Published, with Illustrations, in Demy Bvo., cloth. 

PRICE 12s. 6d. 

PRACTICAL STUDIES 

:F:Bi?.:M:Ei#Tj^.Tioisr, 

Being Contributions to the Life-History of Micro-Organisms. 

By EMIL. CHR. HANSEN, Ph.D., Professor and Direftor at the 

Carlsberg Laboratory, Copenhagen. Translated by Alex. K. 

Miller, Ph.D., Manchester, and Revised by the Author. 

London : E, & F. N. SPON, Ltd., 125, Strand. 

RED-WOOD LAKES 

Free from Aniline, 

as Crimson Lake, Cochineal Red, Purple Lake, &c., 

Supplied as a SPECIALITY by 

Dr. BODENSTEIN and KAESTNER, 

Red-Colour Manufa(5lurers, 

(Established 1840), 

SAALFELD-ON-5AALE, GERMANY. 



A ssistant wanted in London Laboratory; one 

*■ ■^ accustomed to Mellurgical Work. — Address Bo.x No. 99, Che- 
mical News Office, 6 & 7, Creed Lane, Ludgate Hill, London, E.G. 

A nalyticaland Manufacfluring Chemist wanted. 

■*^^ One with a good knowledge of the Manufafture of Small 
Chemicals preferred. — Please apply, in stri(5t confidence, giving full 
information as to age, experietice, and salary required, to " Manu- 
fa(5turer," Chemical News Office, 6 & 7, Creed Lane, Ludgate Hill, 
London, E.G. 



A nalytical Chemist (26) well acquainted with 

■^^ the manufa(5lure of the raw materials, and of the Aniline and 
Coal Tar Dyes, is now open for engagement as Chemist to a Works 
engaged in this industry. Well acquainted with all the processes of 
dyeing and inorganic research work. An accurate and reliable 
analyst ; highest testimonials. — Address " Aniline," Chemical News 
Office, 6 & 7, Creed Lane, Ludgate Hill, London, E.C. 



Analytical Chemist, eleven years' experience, 
desires post in Laboratory or Works, home or abroad. Experi- 
enced in the management of men and machinery ; has taken highest 
University Honours. — Address, stating particulars, to *' Analyst," 
chemical News Office, 6 & 7, Creed Lane, Ludgate Hill, 
London, E.C. 



Gentleman, aged 27, qualified Analytical Che- 
mist, of some years' training and experience, wishes to enter 
an established firm or company with a view to future partnership or 
advancement. — Address " Chemist," care of Deacon's Advertising 
Offices, Leadenhall Street, E.C. 



Chemist, Dipl., open for engagement. Nine 
years' i;rai5tical experience in large English Alkali Works ; 
has had charge of men and machinery ; well up in the manufadlure 
of Sulphuric Acid, Caustic, Bleach, Chlorate, Bichromates, Manga- 
nate of Soda, Strontia Salts, Copper Sulphate, and in large scale 
eleiStro-chemical work. — Address, " Diploma," Chemical News 
Office, 6 & 7, Creed Lane, Ludgate Hill, London, E.C. 



PATENTS, DESIGNS, AND TRADE MARKS ACTS, 
1883 TO 1888. 

INJOTICE IS HEREBY GIVEN, that 

-^^ HENRY ROBERT ANGEL, of 7, St. Helen's Place, 
London, E.C, has applied for leave to amend the Specification filed 
in pursuance of the Application for Letters Patent, No. 335, of 1896, 
for "Improvements in the Manufa(5iure of Caustic Soda, Carbonate 
of Soda, and Sulphide of Sodium." 

Particulars of the proposed amendments were set forth in the 
Illustrated Official Journal (Patents), issued on the 27th January, 1897. 
Any person, or persons, may give notice of opposition to the 
amendment (on Form G) at the Patent Office, 25, Southampton 
Buildings, London, W.C., within one calendar month from the date 
of the said Journal. 

(Signed) H. READER LACK, 

Comptroller General. 

CARPMAEL&CO., 

24, Soutnampton Buildings, 

London, W.C. 

Agents for Applicant. 

Mr. J. G-. LORRAIN, M.I.E.E., M.I.M.E, M.S.C.I., 

Fellow of the Chartered Institute of Patent Agents, 

Norfolk House, Norfolk Street, London, W.C. 

" PATENTEE'S HANDBOOK " Post Feee on application. 



THE ALKALI-MAKER'S HANDBOOK. 

BY 

GEORGE LUNGE, Ph.D., 

Professor of Technical Chemistry, Zurich, 

and 

FERDINAND HURTER, Ph.D., 

Consulting Chemist to the United Alkali Co., Limited. 

Tables and Analytical Methods for ManufatSurers of 
Sulphuric Acid, Nitric Acid, Soda, Potash, and 
Ammonia. Second Edition, Enlarged and thoroughly 
Revised. In crown 8vo., with Illustrations, los. 6d. ; 
strongly bound in half leather, 12s, 
" The present edition gives abundant evidence that care is being 
taken to make the book a faithful record of the condition of contem- 
porary quantitative analysis."— Prof. T. E. Thorpe in Nature. 
" That excellent book." — The late Prof. W. Dittmar. 
" It is an excellent book, and ought to be in the hands of every 
chemist."— Prof. I. J. Hummel. 

London: WHITTAKER & CO., Paternoster Square, E.C. 



Cbbmioal MBWB, I 
Feb. n. 1897. I 



Efficiency 0/ the Hermite Bleaching Solution. 



73 



THE CHEMICAL NEWS 



Vol. LXXV., No. 1942. 



NOTE ON THE LIMIT OF ACCURACY 

ATTAINABLE IN COLORIMETRY. 

By CHARLES W. FOLKARD. 

As the result of a large number of experiments in 1893 
and 1896, the author has come to the conclusion that 
analytical processes depending on the exadt imitation of 
the colour of a solution of unknown strength by another 
solution containing a known amount of the substance (as 
in Nesslerising, &c.), are capable of affording results of 
far greater accuracy than has been generally supposed. 

By taking proper precautions it is possible to work 
colorimetricallyto within one-fortieth or one-fiftieth (say, 
2 per cent), and by averages to within i per cent of the 
quantity of substance present («.§'., copper in ammoniacal 
solution). 

This was at first so startling that publication was 
deferred, but further experience has afforded ample con- 
firmation as regards azure blue, yellow, and red solutions, 
and the object of this note is to ascertain if other ob- 
servers (more particularly works' chemists) have been 
led to a similar conclusion in the course of their daily 
practice. 

Ealing, February 5, 1897. 



THE EFFICIENCY OF THE HERMITE 

BLEACHING SOLUTION. 

By CLAYTON BEADLE. 

As far as I am aware there are no published results of 
experiments upon the bleaching efiSciency of the Hermite 
bleaching solution in comparison with that of a solution 
of bleaching-powder upon the bleaching of cotton and linen 
fibre. All the published results — viz., those of Messrs. 
Cross and Bevan, and Professor Piftet — are, I believe, 
upon the bleaching of wood pulp. 

I made a series of experiments to determine whether 
the Hermite solution still gave the same efficiency when 
used for bleaching cotton and linen rags and rag half- 
stuff. For this purpose a small beater was used, similar 
in construdtion to the paper-maker's hollander. I took 
half-stuff produced from second quality linen rags and 
from second quality cotton rags. Before doing experi- 
ments in the small beater, I mixed a known weight of 
each of the half-stuffs with a carefully ascertained volume 
of Hermite solution, also with bleaching-powder solu- 
tion, the chlorine strength of each having been carefully 
ascertained. 

The time required to bleach the materials to a full 
white was noted, and when the bleaching was complete 
the available chlorine in the residual liquors was deter- 
mined, and the amount of chlorine consumed by the 
fibre calculated. The following are the results : — 

Put in. 







Dry 

weight. 


Strength Percent 




Half-stuff. 


Liquor. per litre, on fibre 






Grms. 


Grms. 


I. 


Linen . . 


1 62 '6 


Hermite .. 2'8 i7'2 


2. 


•1 •• 


i62'6 


Bleaching pd. 3*i6 i9"4 


S> 


Cotton .. 


1762 


Hermite .. 2'8 is-g 


4- 


II • • 


I76'2 


Bleaching pd. 3*16 i8'o 







C0N6UUBD. 






Chlorine. 


Chlorine. 


Time oi 




Grms. 


P.c. on fibre. 


bleaching. 


I. 


2 '44 


1-5 


30 mms 


2. 


372 


2-29 


4 hrs. 


3- 


4-0 


2*27 


2 hrs. 


4- 


6'49 


3-68 


10 hrs. 



The efficiency of chlorine in the Hermite liquid as 
compared with that of chlorine in ordinary bleaching- 
powder is claimed by the inventors to be as 5 is to 3. 
This has been substantiated by the results of Messrs. 
Cross and Bevan, and Professor Pidet. 

3:5::!: 1-66. 

Comparing this with the experiments above, — 



I and 2. 
3 and 4. 



Hermite. 
1-5 : 
2*27 ; 



Bleaching 
powder. 

2-35 
3-68 



154 
165 



These results therefore confirm fairly closely those of 
other observers. The next two experiments were done 
with a view of finding how long the Hermite solution 
took to exhaust itself if the chlorine put in was the exaA 
amount necessary, according to the above experiments, to 
do the bleaching. The rate of bleaching was much 
slower than if the chlorine had been used greatly in 
excess. After three days, however, the liquid only con- 
tained the least possible trace of chlorine, and the fibre 
appeared to be perfedly bleached. 

The preceding experiments were all done with " still " 
liquor. In the following experiments the half-stuff was 
put into the small beater, and the Hermite liquor allowed 
to flow round the beater, and washed out again by means 
of a washing drum, from whence it was delivered to a 
store tank and then again to the beater. The total 
amount of liquor was first of all measured both into the 
beaker and into the store tank, from which a sample was 
taken and tested for chlorine. This experiment was not 
done under the most favourable circumstances, as the 
liquor was drawn from the store tank and not from the 
electrolysing tank whilst the eledtrolysis was going on, 
which I think would have made a considerable difference 
to the results. 

Put in. 
Volume of 
liquid. 



Half-stuff. 

Linen . 
Cotton . 



Weight of 
chlorine. 



Weight 
dry fibre. 

Grms. 
. 542 

• 470 



56*I2 
56'i2 



Strength 
per litre. 
Grms. 

2*64 

2'64 



Per cent 
on fibre. 



27-3 
31-5 



5-6 
5-6 



Consumed. 
Per cent on 
fibre. 

1-03 
1*20 



Time. 
40 mins. 
60 „ 



It is evident that the circulating liquor is more econo- 
mical than the non-circulating. 



Non-circulating Circulating 

Half- chlorine chlorine 

stuff. consumed. consumed. 

Linen .. 1*5 1*03 

Cotton.. 2*27 I "20 



Saving by 

circulating over 

non-circulating. 

30 p.c. 

47 t, 



My results confirm those of other observers as regards 
the rapidity of bleaching by the Hermite solution, which 
I found to bleach very rapidly, doing as much work in 
thirty minutes as bleaching-powder solution of the same 
strength would do in three hours. I also found that 
Hermite solution will bleach in one treatment, when any 
amount of bleaching-powder will fail to do so without an 
intermediate acid treatment. It can be used either circu- 
lating or stored in tanks for use like ordinary bleaching- 



74 



Viscose and Viscoid. 



' CHBHICAt NBWt, 
Feb. la, 1897. 



powder, but the latter, as we have seen, does not give 
such good results. 

Laboratory, West Street, Eritb, 
January 2|, 1897. 



VISCOSE AND VISCOID.* 
By CLAYTON BEADLE. 

In August, 1894 (yournal of the Franklin Imtitute, 
cxxxviii.. No. 824), I had the honour of reading a paper 
before the Franklin Institute upon some new cellulose 
derivatives which had been discovered and partly worked 
out by my colleagues, Messrs. C. F. Cross and E. J. Bevan, 
and myself. Mr. Arthur D. Little, of Boston, took up 
the subjed on this side of the water, and the samples 
which we showed you at that time were produced by him. 
Since then we have added considerably to our knowledge 
of these derivatives. The basis of these products is a 
substance to which we have given the name "Viscose." 
Viscose is chemically cellulose xanthate, the preparation 
and constitution of which is fully explained and set forth 
in my previous paper (vide ut supra). 

The dry regenerated cellulose obtained from the viscose 
solution we have named " Viscoid." 

It is impossible, in a paper of this length, to give a 
history of all the work ws have done in the last two 
years in connection with viscose ; so I have chosen to 
confine myself to certain branches of the work, the 
description of which, I trust, will prove interesting to the 
members of the Institute. 

Manufacture of Alkali Cellulose. 

In the manufadlure of viscose on a large scale, we first 
endeavoured to discover what materials could be utilised, 
and in the course of our work we found that any kind of 
cellulose could be used, provided that it was fairly pure. 
The fibres, however, should be very short indeed ; the 
process depends as much upon the length of the fibre as 
upon the purity of the eellulose. As an instance of this, 
if raw cotton be used without any disintegration it is 
almost impossible to mercerise it and convert it into vis- 
cose ; but if the fibre be disintegrated so as to break up 
the ultimate fibre into pieces of about one-twentieth of 
the length of the original, the mercerisation and conver- 
sion into viscose is rapid and complete. With regard to 
the purity of the fibre, bleached wood generally yields a 
better viscose than unbleached wood, but it is next to 
impossible to convert mechanical wood (i. e., wood dis- 
integrated by mechanical means, and containing a large 
amount of resin and other impurities) into viscose. The 
alkali cellulose often requires to be kept for several d ays 
before treatment with carbon bisulphide; but when the 
disintegration of the fibre is thorough, and the mixture 
with caustic properly effected, the maturing of the alkali 
cellulose is almost unnecessary. 

One great precaution, which at first we lost sight of, 
was to prepare the alkali cellulose without conta(a with 
the atmosphere. 

This we discovered by analysing a number of samples. 
We found that on an average about 50 per cent of the 
alkali had been carbonated during mercerisation, and thus 
rendered useless for the readtion. Alkali cellulose is con- 
verted by the aftion of the CO2 of the atmosphere into 
sodium carbonate and cellulose without our knowing it. 
This change was the cause of a large number of failures, 
which necessitated condudting a series of trials under 
varying conditions, in which we determined the amount 
of alkali carbonated. 

At last we arrived at a method of producing the alkali 
cellulose by which only 5 per cent to 10 per cent of the 
total soda is converted into carbonate. 



Journal of the Franklin Institute^ January, 1897. 



Yield of Viscoid. 

A great deal of work has been done upon the amount 
of viscoid yielded by different celluloses. Pure cotton 
yields somewhat more than its own weight. This is due 
to a change in the cellulose molecule (vide Beadle, yourn. 
of the Franklin Inst., cxxxviii., No. 824). Wood, on the 
other hand, even when thoroughly bleached and pure, un- 
dergoes a considerable loss, which amounts often to 20 
per cent. This is due to the formation of soluble produds 
during mercerisation. 

We have followed this very carefully, and it appears that 
bleached wood pulp contains oxycellulose, which is largely 
dissolved by caustic soda. Under certain conditions the 
regenerated cellulose has no strength, as when films made 
from viscose solution are found to be rotten. Very great 
care has to be taken in the manufadure of viscose to 
insure that the regenerated cellulose is not injured by the 
treatment. A knowledge of this can be acquired only by 
experience, and those who are thoroughly acquainted with 
the manufacture of viscose can often tell at a glance, from 
the appearance of the alkali cellulose or the viscose solu- 
tion, whether a satisfadtory produd will be obtained. These 
conditions are now well understood by us, so that we can 
insure that the cellulose is always regenerated in the 
proper physical condition required for the particular pur- 
pose to which it is to be applied. 

Production of Veneers. 

Mention was made in my previous paper (Journal of 
the Franklin Institute, vol. cxxxviii.. No. 824) of cutting 
pieces from the coagulum and annealing them under pres- 
sure for the produdtion of sheets. This has been worked 
at on a larger scale. The viscose has been run into 
redlangular moulds, and the coagulation of the mass has 
been effedled by exposure to a hot damp atmosphere. 
These masses, weighing from 250 to 400 pounds, have 
been dehydrated by exposing them to an atmosphere 
which is gradually raised in temperature. When the 
blocks have been sufificiently hardened, they are cut into 
sheets about 24 X 18 inches, by a guillotine specially 
construdted for the purpose. By an automatic gear the 
bed on which the guillotine rested was made to travel 
forward at every stroke of the knife, and the amount of 
travel could be regulated at will, so that sheets of any 
thickness could be cut. By this means we were able to 
cut about twenty sheets per minute. 

The sheets were deprived of the chemical by-produdts, 
and then submitted to heavy pressure, by means of which 
the cellulose hydrate was dehydrated down to a compadl 
sheet of cellulose. We had a difficulty by this method in 
obtaining our dehydrated sheets free from strudure. They 
had a tendency to split in laminae. The fradture had 
every appearance of slaty cleavage (Chemical News, 
vol. Ixx., p. 139), and the planes of cleavage were found 
always to be at right-angles to the diredtion in which the 
pressure was applied. With thin sheets we had less 
trouble, and I believe the reason of this was that the 
sheet was thinner than the laminae. In order to avoid 
this difficulty with thicker sheets, we were obliged to 
dehydrate the coagulum to a greater extent, by exposure 
to a hot atmosphere of steam before applying the pres- 
sure. The fad of pressure on the coagulum giving rise 
to slaty cleavage, prevented us from applying pressure 
for moulding solid articles from the coagulum. This 
is obvious when we take into consideration the fadl 
that the dehydrated laminae formed on the outer sur- 
faces by the first application of pressure, prevents 
the egress of moisture from the interior, and, as it were, 
seals the interior from further dehydration. We found it 
next to impossible to mould articles of any thickness under 
pressure from the coagulum for this reason, even on the 
application of a pressure of several tons to the square inch. 
When, however, the sheets are almost dried by exposure to 
warm air, or by one of the processes described subsequently 
for the produdtion of solids, they can be embossed and 



Ohkmical News, I 
Feb. 12,1897. / 



•Report of Commitiee on A tomic Weights. 



75 



stamped into small articles, such as buttons, which are 
sufficiently strudlureless for all pradtical purposes. 

When the sheets are completely dried they offer too 
great a resistance for moulding under pressure. Viscoid 
sheets can be produced by the above process in almost 
any colour, either translucent or opaque, and they can be 
prepared in such a way that they are either soft and 
pliable, or stiff and horny like celluloid. Under pressure 
they can be embossed in various patterns. 
(To be continued). 



THIRD ANNUAL REPORT OF COMMITTEE 

ON ATOMIC WEIGHTS. 

RESULTS PUBLISHED DURING 1895.* 

By F. W. CLARKE. 

To THE Members of the American Chemical Society. 
Your committee upon atomic weights respedtfuUy sub- 
mits the following report, summarising the work done in 
this branch of chemistry during 1895 — a year which may 
be well called eventful in the history of the science. Two 
new elements, argon and helium, have been made known 
to the world, and from the most unexpedted sources ; the 
colledive works of Stas have been published by the 
Belgian Academy, as a monument to his memory ; Prof. 
Morley's great research upon oxygen is at last finished ; 
and a goodly number of other important determinations 
have appeared. Incidentally, but pertinently, I may also 
call attention to the Marignac memorial lecture by Cieve 
{jfourn. Ghent. Soc, June, 1895), in which the atomic 
weight researches of the former chemist are well out- 
lined ; and to the extraordinary number of papers upon 
the periodic law, which have been called out by the dis- 
covery of argon and helium. These papers fall outside 
the scope of this report, and they are numerous enough 
to almost warrant a bibliography of their own. 

The H : O Ratio. — Prof. Morley's work upon this funda- 
mental constant has been published in full by the Smith- 
sonian Institute, t and divides itself naturally into four 
parts: — First, the density of oxygen; second, that of hy- 
drogen ; third, the volumetric composition of water ; and 
fourth, its gravimetric synthesis. 

For the density of oxygen, or rather the weight of i litre 
at 0°, 760 m.m.. at sea-level, and in latitude 45°, three 
sets of measurements are given, with the following mean 
values in grms. : — 

Series I i'42879 J; 0*000034 

,, 2 I '42887 ^ 0000048 

„ 3 i"429i7 ^ o"oooo48 

As the third series, on experimental grounds, is re- 
garded by Morley as the best, he assigns it double weight, 
and on this basis the general mean of all three becomes — 
1*42900 i o'oooo34. 

For the weight of a litre of hydrogen under similar 
standard conditions, five series of determinations are 
given, as follows : — 

Series i o'o89938 

,, 2 0*089970 

,, 3 o"o89886 J;' 0*0000049 

,, 4 0*089880 ^ 0*0000088 

„ 5 0*089866 ;J; 0*0000034 

The hydrogen of the first and second series was prob- 
ably contaminated by traces of mercurial vapour, and 



* Read at the Cleveland Meeting, December 31, 1895. From the 
Journal of the American Chemical Society, xviii., No. 3. 

+ " On the Density of Oxygen and Hydrogen, and on the Ratio of 
their Atomic Weigiits." By Edward W. Morley. Smithsonian 
Contributions to Knowledge, 1895. 410. xi. + 117 pages. 40 cuts. 
Abstract in Am. Chem. Joxirn., xvii., 267 (gravimetric); and Ztschr. 
Phys. Chem., xvii., Sy {gsiBeoua densities); also note ia Am. Chem, 
Journ., xvii., 396. 



these results are therefore rejedted by Morley. For the 
third, fourth, and fifth series the eledlrolytic gas was 
occluded in palladium and transferred to the measuring 
globes without the intervention of stopcocks; thus 
avoiding contaiSt with mercury and leakages of external air. 
Their general mean is — 

0*089873 J; 0*0000027. 
Dividing the weight found for oxygen by this value for 
hydrogen the ratio becomes — 

15*9002. 

For the volumetric ratio O : 2H, Morley finds the 
value I : 2*00269. Applying this as a correction to the 
density ratio, we have for the atomic weight of oxygen — 
O = 15*879. 

In his synthesis of water Morley differs from all of his 
predecessors in that he weighed both constituents sepa- 
rately, and also the water formed. In other words, his 
syntheses are complete, and take nothing for granted. 
The weights in grms. are as follows : — 



I 
2 
3 
4 
5 
6 

7 
8 

9 
10 
II 
12 



O used. 

25*9176 

25-8531 

30*3210 

30*5294 

30*4700 

30*5818 

30*4013 

30*3966 

30*3497 

30*3479 

29-8865 

30*3429 



H used. 
3*2645 
3-2559 
3"8i93 
3-8450 
3-8382 
3-8523 
3-8297 
3*8286 
3-8225 
3*8220 

3-7637 
3*8211 



Water found. 
29*1788 
291052 

34-1389 
Lost 

34-3151 
34-4327 
34*2284 
34*2261 
34-1742 
34-1743 
33-6540 
34-1559 



From these data two sets of values for the atomic 
weight of oxygen are derivable ; one from the ratio H : O, 



the other from the ratio H ; 
joined. 



H2O. These sets are sub- 



H :0. 

1 15*878 

2 15881 

3 15-878 

4 15*880 

5 15-877 

6 15-877 

7 15-877 

8 15-878 

9 15-879 

10 15*881 

11 15881 

12 15*882 



Mean.. 



15*8792 



H : HjO. 

15-877 
15*878 

15-873 

15*881 
15*876 
15-875 
15-879 
15*881 
15-883 
15-883 
15-878 

15*8785 



From the density work the value found was 15-879, and 
the mean of this with the two synthetic results is — 
O = 15*8789. 

Hence, for all pradical purposes, the atomic weight of 
oxygen may be put at 15*88, with an uncertainty of less 
than one unit in the second decimal. 

It is impradlicable, in a report of this kind, to go into 
the details of so elaborate an investigation as this of 
Morley's, and a bare statement of results must suffice. 
The research, however, is one of the most perfedl of its 
kind, every source of error having been considered and 
guarded against, and it will doubtless take its place in 
chemical literature as a classic. Independently of its 
main purpose, the book is almost a manual on the art of 
weighing and measuring gases, and no experimenter who 
engages upon work of that kind can afford to overlook it. 

More recently still, a new determination of the atomic 
weight of oxygen has been published by Julius Thomsen 
(^Ztschr. Anorg. Chem., xi., 14), whose method is quite 
novel. First, aluminum, in weighed quantities, was dis- 



76 



Metal Separations by means of Hydrochloric A cid Gas* { 



Chemical Nbwb, 
Feb. 12, 1897. 



solved in caustic potash solution. In one set of experi- 
ments the apparatus was so construdled that the hydrogen 
evolved was dried and then expelled. The loss of weight 
of the apparatus gave the weight of the hydrogen so 
liberated. In the second set of experiments the hydrogen 
passed into a combustion chamber in which it was burned 
with oxygen, the water being retained. The increase in 
weight of this apparatus gave the weight of oxygen so 
taken up. The two series, reduced to the standard of a 
unit weight of aluminum, gave the ratio between oxygen 
and hydrogen. 

The results of the two series, reduced to a vacuum and 
stated as ratios, are as follows: — 



p;^^^ Weight of H^ 
Weight of Al 
First. 
o'liiSo 
o'liiys 
0*11194 
0*11205 
o'liiSg 

0'II200 

0*11194 
0*11175 
O'liigo 
0*11182 
0*11204 

0'II202 

0*11204 
0*11179 
0*11178 

0*II202 

0-III88 
o*iii86 
o'liiSs 
0*11190 
0*11187 



Second, Weighlom 
Weight of Al 
Second. 



o*i 

0*88799 
0*88774 
0-88779 
0-88785 
0*88789 
0-88798 
0*88787 
0-88773 
0*88798 
0-88785 

0*88787^0*000018 



7-9345 ± o-ooii. 



0*11190^0*000015 

Dividing the mean of the second column by the mean 
of the first, we have for the equivalent of oxygen :— 

0*88787 ^ o*ooooi8 
0*11190 i 0*000015 
Hence, — 

O = 15-8690 i 0*0022. 

The details of the investigation are somewhat compli- 
cated, and involve various corredtions which need not be 
considered here. The result as stated includes all cor- 
redlions and is evidently good. The ratios, however, can- 
not be reversed and used for measuring the atomic weight 
of aluminum, because the metal employed was not abso- 
lutely pure. 

The Stas Memorial.— As a monument to the memory of 
the late Jean Servais Stas, more appropriate than statue 
or column of stone, the Belgian Academy has published 
his collecaed works in three superb quarto volumes.* All 
of his great investigations are here gathered together, 
and in the third volume, entitled " Oeuvres Posthumes," 
some hitherto unpublished data are given for the impor- 
tant ratio between potassium chloride and silver. These 
data are represented by two series : one made with a uni- 
form sample of silver, and chloride from various sources ; 
the other with constant chloride, but with silver of diverse 
origin; the aim being to establish experimentally the 
fixed charadter of each substance. The first series is 
complete ; of the second series only one experiment was 
found recorded among Stas's papers. 

The quantity of potassium chloride equivalent to 100 
parts of silver was found to be as follows : — 



♦ "Jean Servais Stas. Oeuvres Completes.' Edited by W. Spring. 
Bruxelles, 1894. 



69*1227 
69*1236 
69' 1234 
69*1244 
69- 1 235 
69-1228 
69*1222 
69-1211 
69*1219 
69-1249 
69-1238 
69*1225 
6g'i2ii 



Mean of first series 
Second series . . . 



69-1229 
69-1240 

These results give an effective confirmation to Stas's 
determinations of 1882. 

(To be continued). 



METAL SEPARATIONS BY MEANS OF 

HYDROCHLORIC ACID GAS.* 

By J. BIRD MOVER. 

(Concluded from p. 65). 

XV. — Separation of Arsenic from Zinc. 
In some preliminary work zinc oxide was treated with 
acid gas at 200°. It completely changed to chloride, and 
was not volatile. Pure zinc sulphate was used to pre- 
cipitate the arsenate ; it was washed, dried, and ignited 
to 150°. The same difHculty appeared as was encountered 
under iron. Zinc arsenate melts down to a liquid mass 
as soon as the acid gas strikes it, which is extremely hard 
to evaporate without spattering, A small glass cover was 
placed over the boat, which tended to lessen the spat- 
tering, but did not entirely prevent it. 

The zinc was estimated by taking the chloride up in a 
little hydrochloric acid and running it down with pure 
mercuric oxide. It was then ignited and weighed as zinc 
oxide. One good result was obtained, but generally the 
residues of zinc contained arsenic and the results were far 
from being concordant. 

XVI. — The Separation of Arsenic from Cobalt and Nickel. 

Cobalt and nickel were precipitated as arsenates in the 
usual manner, with a solution of pyroarsenate. 

Cobalt nitrate, a Merck preparation, was carefully puri- 
fied ; considerable manganese was found and eliminated. 

This gave the pink salt C03A82O8+8H2O, which was 
ignited to the blue anhydrous compound. 

Cobalt arsenate is very readily attacked by the acid gas 
in the cold, yielding a pink chloride. A slight heat, not 
much above 120°, changed it to the blue chloride and 
drove out the arsenic. At first it was quickly weighed as 
chloride, then it was taken up in a little hydrochloric acid 
and evaporated down with mercuric oxide. On ignition, 
black C03O4 was obtained and weighed. 

The arsenic was eliminated as usual. 



C03AS2O8 taken 
C0CI2 obtained 
C0CI2 required 
C03O4 obtained 
C03O4 required 
Difference 
AS2O5 obtained 
AS2O5 required 
Difference . . 



Experiment I. 


Experiment II 


Grm. 


Grm. 


0*1509 


0*2029 


0*1309 


— 


0*1293 


— 


0*0738 


0*0969 


0*0731 


0*0983 


+ 0-0007 


— 0*0014 


0*0770 


— 


0-0764 


— 


+ 0*0006 


— 



* From author's thesis presented to the Faculty of the University 
of Pennsylvania for the degree of Ph.D., 1-896. From the jfourn. 
Amer. Chem. Soc, xviii., December, 1896. 



*^f".'"S^^T''} Determination of Atomic Masses by the Electrolytic Method. 79 



NiaAszOs+SHjO taken 

NiO obtained 

NiO required 

Difference 



On testing the cobalt residue by the Marsh test, no 
trace of arsenic was found. No cobalt was found in the 
sublimate. Some of the first experiments gave cobalt 
too low ; it was thought that they had been heated too 
high, but testing showed no volatilised cobalt. 

A temperature of 125° is sufficient to drive out all of 
the arsenic, and at this temperature there is no danger of 
volatilising the cobalt. 

In working with nickel, the green arsenate was simply 
dried in the first experiment. It therefore had the com- 
position Ni3As208+8H20. 

Hydrochloric acid gas attacked it in the cold. A slight 
heat drives out the arsenic and moisture and leaves a 
salmon-coloured chloride. The nickel chloride was 
changed to oxide by evaporating it with nitric acid and 

igniting. 

Experiment I. 
Grm. 

0"I502 

.. .. 0-0554 

.. .. 0-0561 

- 0*0007 

In Experiments II. and III. the salt was made anhy- 
drous by ignition. 

Experiment II. Experiment III. 
Grm. Grm. 

NiaAsaOs taken .. .. o'ii66 0-1040 

NiO obtained 0-0577 0-0523 

NiO required 0*0575 0-0513 

Difference ■ho*ooo2 -i-o'ooio 

AS2O5 obtained .... — 0-0515 

A82O3 required . > . . — 0*0526 

Difference — -o'ooii 

The Marsh test showed no arsenic with the nickel. 

XVII. — Behaviour of Minerals in Hydrochloric Acid Gas. 

Niccolite. — One half grm. of the mineral was finely 
powdered and subjected to the adtion of acid gas for a 
day, at a temperature of 200° C. It was only very slightly 
affedted. 

A second portion was dissolved in nitric acid and 
evaporated down in a porcelain dish. It was then trans- 
ferred to a boat and evaporated to dryness. To remove 
all the acid it was heated in an oven to 110° for half an 
hour. The dry substance was adled upon by the acid gas in 
the cold for five hours* It changed completely to chloride. 
A temperature of 150° for an hour removed all the mois- 
ture and arsenic. 

The nickel chloride was evaporated down with nitric 
acid, ignited, and weighed as NiO. The arsenic was esti- 
mated as usual. 

Per cent. 

Nickel found 4379 

Nickel calculated 43'6o 

Difference o-ig 

Arsenic found 56*66 

Arsenic calculated 56*40 

Difference 0*26 

Undoubtedly there is still a wide field open in regard to 
the behaviour of hydrochloric acid gas upon mineral 
species. Smith and Hibbs {loc. cit.) showed that mime- 
tite lost its arsenic quantitatively, when heated in a 
stream of acid gas. In this laboratory others are being 
investigated with favourable indications. The direiSt em- 
ployment of hydrochloric acid gas upon a powdered 
mineral would simplify many a tedious gravimetric pro- 
cess, leaving the separated elements in a desirable con- 
dition for further treatment. 

In the case of a mineral such as niccolite, where it must 
first be decomposed with nitric acid and then transferred 
to a boat, the advantage is not so great, This, however, 
can -be modified, so that the time fador is reduced and 
the advantage of the method still retained. Instead of 
using a boat, which has no advantage unless the non* 



volatile chlorides are to be weighed directly, a hard glass 
bulb can be substituted. The mineral is placed in the 
bulb, dissolved in nitric acid, and evaporated down by the 
aid of a current of air drawn through the bulb. 

The residual oxides are then separated in a stream of 
hydrochloric acid gas as usual. 



THE DETERMINATION OF ATOMIC MASSES 

OF SILVER, MERCURY, AND CADMIUM, 

BY THE ELECTROLYTIC METHOD.* 

By WILLETT LEPLEY HARDIN. 

(Continued from p. 63). 

Part II. {continued). 
Third Series. 
Experiments on Mercuric Cyanide. 
A SERIES of observations was made on several organic 
salts of mercury with a view of selefti g a compound 
suitable for atomic mass determinations. Mercuric 
acetate and other similar salts were found to be unstable 
in the air and unsuited for accurate analyses. Mercuric 
cyanide, on the other hand, was found to be perfectly 
stable and to form well-defined crystals. 

Preparation of Hydrocyanic Acid. 
Five hundred grms. of potassium ferrocyanide were 
placed in a two litre retort connected with a condenser. 
A cooled mixture of 300 grms. of pure sulphuric acid and 
700 c.c. of distilled water was then poured into the retort, 
and the mixture carefully heated until the hydrocyanic 
acid was distilled over into the receiver. The produdl 
obtained was re-distilled and used immediately in the 
preparation of mercuric cyanide. 

Preparation of Mercuric Cyanide. 
Fifty grms. of mercuric oxide, prepared as already 
described in the experiments on mercuric oxide, were 
dissolved in pure warm hydrocyanic acid. The solution 
was then filtered and evaporated to crystallisation. The 
transparent crystals of mercuric cyanide which separated 
were dissolved in pure water and re-crystallised. The 
produdt obtained by the second crystallisation was quickly 
rinsed with cold water and dried for six hours in an air 
bath at a temperature of 50°. The crystals were then 
ground to a finely divided powder in an agate mortar and 
re-dried for twenty- four hours in an air bath at a tempera- 
ture of 55°. The dry white powder was then placed in a 
weighing tube and kept in a desiccator. 

Mode of Procedure. 

The mode of procedure with mercuric cyanide was 
somewhat different from that of the preceding experi' 
ments, in that no potassium cyanide was used in pre- 
paring the solution for eledlrolysis. A weighed portion 
of the material was dissolved in pure water in a platifium 
dish. When the crystals had completely dissolved, the 
dish was filled to within a quarter of an inch of the top 
with water, after which one drop of pure sulphuric acid 
was added. The solution was then ele<5lrolysed, and the 
resulting metal weighed. The strength of the current 
and the time of adlion were the same as for mercuric 
chloride. In the last four experiments, where rather large 
quantities of mercury were deposited, the strong current 
was allowed to ad from two to six hours longer. 

The results of ten experiments on mercuric cyanide, 
reduced to a vacuum standard on the basis of — 



♦ Contribution from the Joha Harrison Laboratory of diemist'y 
No. 13. From the author's thesis presented to the Faculty of the 
University of Pennsylvania for the degree of Ph.D.— From the 
Journal of the American Chemical Society, xvtii., p. 990. 



78 Determination of Atomic Masses by the Electrolytic Method. 

4'o = density of mercuric cyanide, 
13'59 = M metallic mercury, 

21*4 = „ platinum dish, 

8-5 = „ weights, 

and computed for the formula Hg(CN}2, assuming i2'oi 
and 14*04 to be the atomic masses of carbon and nitrogen, 
respe^ively, are as follows : — 

Weight Weight Atomic masa 

of Hg(CN)j. ofHg. of mercury. 

Grms. Grm. 

1 0'55776 0*44252 200*063 

2 0*63290 0*50215 200*092 

3 0*70652 0*56053 200*038 

4 0*80241 0*63663 200*075 

5 0*65706 0*52130 200*057 

6 081678 0-64805 200*103 

7 1*07628 0*85392 200*077 

8 1*22615 0*97282 200*071 

9 1*66225 1*31880 200*057 
10 2*11170 1*67541 200*077 

Mean .. .. = 200*071 
Maximum .. = 200*103 
Minimum .. = 200*038 



Chbuical Nbwbi 

Feb. 12, 1807. 



Difference .. = 0065 
Probable error = 0*005 

From the total quantity of material used and metal 
obtained the atomic mass of mercury is 200*070. 

Fourth Series. 

According to Faraday's law the quantities of different 
metals deposited from their solutions by the same current 
are proportional to their equivalent weights. In this 
series of experiments an attempt was made to determine 
the ratio of the atomic mass of mercury to that of silver 
by passing the same current through the solutions of the 
two metals and weighing the two resulting deposits. If 
the proper conditions could be obtained, this would 
certainly be the simplest and most diredt method for com- 
paring the equivalent weights of different metals. But so 
many difiSculties were met that the method on the whole 
was not satisfadtory. 

In the " Revision of the Atomic Weight of Gold " 
{Atner. Chem. yourn., xii., 182), Mallet made use of this 
method, and in a series of careful preliminary experi- 
ments determined the conditions most favourable to its 
application. From a number of experiments made by 
passing the same current through two different solutions 
of copper sulphate, using pure eledrotype copper for both 
anode and cathode in each solution, Mallet found ; — 

First. — Other conditions being the same, the difference 
in the quantities of metal deposited from solutions of 
unequal concentrations was very slight and somewhat 
variable, but the tendency was toward a slightly larger 
quantity from the more concentrated solution. 

Second. — With equal quantities of metal in the two 
solutions, and unequal quantities of free acid, the differ- 
ence in the results obtained were almost insignificant 
and somewhat variable in diredtion, the tendency being 
toward a slightly larger quantity from the less acid solu- 
tion. 

Third. — Other conditions being the same, a difference 
in the temperature of the two solutions invariably caused 
a slightly larger deposit from the cooler solution. 

Fourth. — Other conditions being the same, a difference 
in the size of the copper plates, and hence a difference in 
the •'current density," caused a slightly greater deposit 
on the smaller plate. 

Fifth. — A difference in the distance between the two 
plates did not produce a constant difference of result, but 
the tendency was toward a slightly larger deposit on the 
cathode plate farther separated from its anode. 

From the foregoing experiments it is evident that the 
conditions most favourable to this method are, that the 
two solutions should be equally concentrated, of the same 



temperature, and should contain equal amounts of free 
acid, or when the double cyanides are used, equal quanti- 
ties of free potassium cyanide. And, moreover, that the 
two cathodes and also the two anodes should be of the 
same size, and that the distance between the anode and 
cathode should be the same in both solutions. These 
conditions were closely observed throughout this work. 

Arrangement of Apparatus. 

The deposits in this series of experiments were made 
in two platinum dishes of equal capacity and equal 
internal area. The anode in each case consisted of a 
coil of rather large platinum wire, the two coils being of 
the same shape and size. The dishes were insulated 
from each other by means of two glass stands. The 
platinum coils were completely immersed in the solutions, 
and the portion of the wire near the surface of the liquid 
was covered with paraffin to prevent surface contadt. The 
current, after passing through the two solutions, was 
allowed to pass through a hydrogen voltameter in order 
that its strength might be observed at any time. 

In the second arrangement of apparatus the platinum 
dishes were made the anodes, and two pieces of platinum 
foil of the same shape and size were used for the cathodes. 
The results, however, from this second arrangement were 
not as satisfadlory as from the first. 

Mode of Procedure. 

A solution of the double cyanide of silver and potassium 
was placed in one of the platinum dishes, and a solution 
of the double cyanide of mercury and potassium in the 
other. The quantities of silver and mercury present in 
their solutions were approximately proportional to their 
equivalent weights. Each solution contained a slight 
excess of potassium cyanide. The dishes were placed 
in their positions, and the anodes immersed some time 
before the current was allowed to ad. When the tem- 
perature of the two solutions was the same as that of the 
room the connection was made, and the same current 
allowed to pass through the two solutions. The quantity 
of metal deposited was never allowed to exceed one-half 
of the metal present in the solution at first. Before 
interrupting the current, the solutions were syphoned from 
the two platinum dishes at the same time with two 
syphons of the same bore. The deposits were then 
washed several times with boiling water, carefully dried, 
and their weights determined. Experiments were made 
with currents of different strength, and with solutions of 
various degrees of concentration. The results obtained 
were far from being satisfactory. The strength of current 
which seemed best adapted to the work was that which 
deposited about one-tenth of a grm, of silver per hour. 

From a large number of experiments, only seven results 
were obtained which seem of any value in determining 
the atomic mass of mercury. And it must be added that 
many others were rejedled, not because they were known 
to be vitiated in anyway, but because the results obtained 
for the atomic mass of mercury differed from those 
obtained from other methods. It is possible that, in a 
large number of experiments the condition would be more 
favourable in some than in others, but whether the close 
agreement of the results seledled was due to this or to 
the balancing of errors could not be determined. , 

Seven results computed on the basis of 107*92 for the 
atomic mass of silver are as follows. (See next column). 

Computing from the total quantities of mercury and 
silver obtained we have 199*971 for the atomic mass of 
mercury. 

Although the cause of the large variation in the rejeded 
observations could not be definitely determined, several 
sources of error suggest themselves. 

First, small quantities of hydrogen were undoubtedly 
set free in the process of eledlrolysis, and unless these 
quantities were always equal in the two solutions, which 
is not probable, an error would be introduced. 

Second, in some solutions an error might easily be 



CtaBUICAL NlWSil 

Feb. 12, 1897. I 



Aluminum Analysts, 



79 











Atomic mass 




Weight of Hg. 


Weight of Ag. 


of mercury. 




Grm. 


Grm. 






I 


O'06l26 


0*o66lo 




200-036 


2 


0-06190 


0-06680 




200-007 


3 


0'078i4 


0*08432 




200-021 


4 


0*10361 


0-lll8l 




200*011 


5 


0'15201 


0-16402 




200-061 


6 


0-26806 


0*28940 




199-924 


7 


0-82808 


0*89388 




199-929 




Mean .. 


.. =199 


996 






Maximum 


.. =s 200 


061 






Minimum 
Difference 


.. = 199-924 






.. = 


137 





introduced by a change in the atomicity of mercury, but 
in a solution of the double cyanide of mercury and potas- 
sium this change is hardiy probable. 

Third, the occlusion of hydrogen by the two metallic 
deposits would also be a possible source of error; but 
only small errors could be introduced in this way. 

To account for the difference of several units in the 
results, the source of error first mentioned seems by far 
the most probable. 

Summary. 

In the discussion of the results obtained in the different 
series of observations on the compounds of silver, the 
probable sources of error and likewise the advantages of 
the method were pointed out. The same discussion 
applies equally well to the observations on mercury. 

It is evident that the first three series of observations 
on mercury are entitled to more weight than the last 
series. Just why the results on mercuric bromide should 
be lower than those on mercuric chloride is not clear. 
Both compounds are certainly well adapted to atomic 
mass determinations, inasmuch as they can be purified 
by both crystallisation and sublimation. The most pro- 
bable impurity in mercuric bromine would be mercuric 
chloride, but that would tend to increase rather than 
lower the results. The series of observations on mercuric 
cyanide have, perhaps, one advantage over the others, in 
that no potassium cyanide was used. The results obtained 
in this series are still higher than those obtained from 
mercuric chloride, and almost two-tenths of a unit higher 
than those obtained from mercuric bromide. However, 
as the same care was exercised in the purification of the 
material for each of the three series, and as there was no 
apparent error in either case, equal weight must be given 
to each of the three series in determining the most pro- 
bable value of the atomic mass of mercury. And, as the 
mean of the last series is almost identical with the mean 
of the first three, equal weight can be given to this series 
without introducing any error. 

Computing the general mean from the separate observa- 
tions we have : — 

Atomic mass of mercury. 

First series 200-006 

Second „ 199-883 

Third ,, 200*071 

Fourth ,, 199-996 

General mean = 199*989 

From the total quantities of material used and metal 
obtained, the general mean is : — 

Atomic mass of mercury. 

First series 199-996 

Second „ ,. 199-885 

Third ,, 200-070 

Fourth , 199*971 



Combining this with the first general mean we have :- 

Atomic mass of mercury. 
First general mean . . . . = 199*989 
Second „ ,, .. .. = 199-91 1 



General mean — 199*981 



Most probable mean of all the results = 199*985 
or 200 for the atomic mass of mercury. 
(To be continued). 



ALUMINUM ANALYSIS.* 

By JAMES OTIS HANDY. 

(Concluded from p. 68). 

Hydrated Alumina. 
Hydrated alumina is analysed for water, silica, and 
sodium carbonate. 

Water. — Ignite i grm. in a closely covered crucible, at 
first gently and then intensely for fifteen minutes over the 
strongest blast. The loss on ignition includes water and 
the carbon dioxide of the sodium carbonate. Calculate 
the carbon dioxide from the sodium oxide found and de- 
dudt it from the loss on ignition. 

Silica. — Hydrated alumina is soluble in sulphuric acid 
of42°B. The silica, however, is left undissolved. 42° 
B. sulphuric acid is made by mixing 900 c.c. of concen- 
trated sulphuric acid with 1290 c.c. of water. Five grms. 
of hydrated alumina are treated with twenty-five c.c. of 
42° B. sulphuric acid and heated until the alumina appears 
to be all dissolved. Dilute to 100 c.c. and boil. Filter, 
wash, ignite, and fuse the residue with one grm. of potas- 
sium bisulphate and cool. Dissolve in water, filter, wash, 
ignite, and weigh in crucible, treat with sulphuric acid 
and hydrofluoric acid, evaporate, ignite, and weigh again. 
Loss equals silica. 

Soda. — The method of the determination of soda is the 
same in calcined and hydrated alumina. The method is 
that of J. L. Smith, and is described under *' Sodium in 
Aluminum." Calculate sodium chloride to sodium car- 
bonate, if the sample is hydrated, and to sodium oxide if 
the sample is calcined alumina. 

Calcined Alumina. 

Water and soda are determined as in hydrated alumina. 

Silica, — Fuse i grm. of the finely ground alumina with 
10 grms. of potassium bisulphate. If this does not make 
a clear fusion add 2 grms. of bisulphate and heat up again. 
Dissolve the fusion when cool in water and filter. Burn 
off the insoluble residue. Fuse it with i grm. of sodium 
carbonate and cool in fifteen c.c. of water in a four-and- 
a-half-inch evaporating dish. Add twenty-five c.c. of 25 
per cent sulphuric acid. When all soluble matter has 
dissolved, remove the crucible and evaporate down until 
sulphuric acid fumes escape. Cool, dilute with water, 
boil, filter, ignite, and weigh silica plus crucible, treat 
with sulphuric and hydrofluoric acids, and weigh again. 
Loss equals silica. 

Analysis of Bauxite. 
(Method adopted. May, 1895.) 

No unusual apparatus or reagents are required. 

One and five-tenths grms. of very finely ground bauxite 
(previously dried at 100° C. and bottled), is taken for 
analysis. Weigh into a five-inch porcelain evaporating 
dish and dissolve in fifty c.c. of acid mixture. This mix- 
ture is the same as that used for aluminum analysis. 
Boil the solution down until fumes escape and keep the 
residue fuming strongly for about fifteen minutes. Cool, 
add 100 c.c. of water, stir and then boil for ten minutes. 
Filter, wash well with water, receiving the filtrate in a 
beaker of about 300 c.c. capacity. The filtrate and washings 

* From the Journal of the American Chemical Society, Sept.| i8g6. 



8o 



Action of Wagner's Reagent upon Caffeine. 



I CbbmicalNbws, 
t Feb. 12, i8g7. 



should amount to about 175 c.c. Burn off the insoluble 
residue (which consists chiefly of silica, with a little 
titanic acid, oxide of iron, and alumina) and weigh it in 
the crucible, add three drops of 25 per cent sulphuric acid 
and about five c.c. of hydrofluoric acid and evaporate 
slowly to dryness. Ignite very strongly and weigh. 
The loss in weight equals silica. Add to the residue in 
the crucible i grm. of potassium bisulphate and fuse 
quickly and thoroughly over a Bunsen burner, cool and 
place the crucible in the beaker containing the main sul- 
phuric acid solution. The small residue from this fusion 
will be silica, and is to be added to the silica already 
found. Having obtained the sulphate solution containing 
all the alumina, ferric oxide, and titanic oxide, make it up 
to 550 c.c. and mix. Then fifty c.c. will equal three- 
tenths grm. bauxite. Take fifty c.c. and dilute to 300 c.c. 
Add two c.c. of concentrated hydrochloric acid and am- 
monia in slight excess, boil for five minutes, let the pre- 
cipitate settle, filter, and wash very thoroughly with hot 
water. Test the filtrate for further alumina by boiling. 
Burn off the filter paper and ignite the precipitate very 
strongly after crushing all the lumps of alumina. Weigh 
alumina, ferric oxide, and titanic oxide. 

Titanic Acid, — Take too c.c. of the original sulphate 
solution (six-tenths grm.), add ammonia until a slight 
permanent precipitate is formed, then add sulphuric acid 
from a pipette or burette until this precipitate just re-dis- 
solves. Finally add i c.c. more of 25 per cent, sulphuric 
acid and dilute to 400 c.c. If the bauxite is high in iron 
(which will be indicated by the distindt yellow colour of 
this solution) sulphur dioxide gas must be run into it 
until it is decolourised and smells strongly of sulphur 
dioxide, but if the solution is nearly colourless, indicating 
a low percentage of iron, only sulphur dioxide water need 
be used for the redu(^ion. Boil well for one hour, adding 
water saturated with sulphur dioxide occasionally. Filter 
ofTthe titanic oxide through double filters, and wash well 
with hot water. If the precipitate is yellow, indicating 
the presence of iron, it can be fused with i grm. of potas- 
sium bisulphate, the fusion dissolved in water, and the 
iron determined in this solution by reducing with zinc 
and titrating with permangate. This is not often neces- 
sary. 

Oxide of Iron. — Take 50 c.c. of the sulphate solution, 
add 10 c.c. of dilute sulphuric acid, and i grm. of granu- 
lated zinc, and set the beaker in a warm place. When 
reduced, filter and titrate the iron with standard potassium 
permanganate. More zinc is used for bauxites high in 
iron. 

Method for Iron Determination, using a larger Quantity 
of Bauxite. (Applicable to Purest Ores). 

Place a half grm. of the finely powdered ore in a large 
platinum crucible, and add 3 c.c. of 25 percent, sulphuric 
acid and 5 c.c. of hydrochloric acid, and evaporate very 
slowly to fumes ; drive off the excess of sulphuric acid by 
heat, boil out the residue with water, and add 10 c.c. of 
dilute sulphuric acid. Remove the crucible and reduce 
with zinc, as above, and titrate. 

Water and Organic Matter. — Ignite three-tenths grm. 
cautiously at first and finally very strong in a covered 
crucible. The loss of weight equals water and organic 
matter. 



ON THE ACTION OF WAGNER'S REAGENT 

UPON CAFFEINE, AND 

A NEW METHOD FOR THE ESTIMATION 

OF CAFFEINE.* 

By M.GOMBERG. 

The use of iodine in potassium iodide as a general quali- 
tative reagent for alkaloids dates as far back as 1839 



. * From the jfournal of the American Chemical Society, xviii.. No. 4- 



(Bouchardat, Comp. Rend., ix., 475). It was, however, 
R. Wagner {Dingl. Poly, ^ourn., clxi., 40 ; Ztschr. Anal. 
Chem., i., 102) who first employed it for the quantitative 
estimation of vegetable bases, and this solution has since 
been known as Wagner's reagent. He based his con- 
clusion upon trials with solution of quinine and cincho- 
nine, showing that under approximately similar conditions 
they always require the same amount of iodine for com- 
plete precipitation. Hence empirical fadtors could be 
established which would enable one to use a standard 
solution of iodine for the titration of all such alkaloids as 
form insoluble superiodides. The method, however, was 
not frequently employed, for the reason that there was 
no experimental proof as to the constancy of composition 
of the precipitates. Moreover, it was noticed that some 
of the precipitates give up a portion of their iodine to 
water, i.e., they are not completely insoluble. Hence 
concordant results could not be obtained. Later, Schweis- 
singer {Arch. d. Pharm., Ixiv., 615, 1885) applied this 
method to the estimation of strychnine and brucine. His 
results have led him to the conclusion that while the 
method is very satisfadtory for strychnine, it is far from 
being so for brucine. Recently Kippenberger (Ztschr. 
Anal. Chem., xxxiv., 317 ; xxxv., 10), in his research upon 
the isolation and separation of alkaloids for toxicological 
purposes, has reviewed the subjedt of the ai^ion of 
Wagner's reagent upon alkaloids, and gives considerable 
prominence to this as one of the best methods for the 
estimation of the vegetable bases. His method of pro- 
cedure was pradlically the same as that first proposed by 
Wagner. The alkaloid is dissolved in acidulated water, 
and to the solution a tenth or twentieth normal solution 
of iodine in potassium iodide is gradually added until all 
the alkaloid is precipitated and the supernatant liquid 
shows a slight excess of iodine. Instead of filtering and 
washing the precipitate, as was done by Wagner and 
Schweissinger, Kippenberger allows the precipitate to 
settle, and either decants or filters off an aliquot portion 
of the mother-liquid for the estimation of iodine not taken 
up by the alkaloid. The estimation of iodine is always 
done by means of a standard solution of sodium thio- 
sulphate. 

It has been usually assumed, for reasons not entirely 
clear, that the composition of the precipitates is 
Alk.HI.I2, i.e., diiodides of the hydriodides of the alka- 
loids are formed. Of the three atoms of iodine only two 
can be estimated diredtly by titration with sodium thio- 
sulphate. The hydriodic acid is supposed to come from 
the potassium iodide, while the two " superiodine " atoms 
are furnished by the free iodine dissolved in the potassium 
iodide. The quantity of an alkaloid precipitated by a 
known volume of Wagner's reagent is calculated on this 
assumption, 2I: molecular weight of alkaloid : : amount 
of iodine taken up : ;«r = amount of alkaloid. Schweis- 
singer found that the method of calculation agrees entirely 
with the theoretical figures for strychnine. Kippenberger 
has called into question the corredtness of this mode of 
calculation. He, too, assumes that the composition of 
the precipitates is to be represented by the formula 
Alk.HI,l2, but he claims that all three atomsof iodine are 
supplied by the free iodine, and none by the potassium 
iodide. Therefore the calculation of the amount of alka- 
loid precipitated is to be done, according to Kippenberger, 
by the use of the proportion, 3I : molecular weight of 
alkaloid : : amount of iodine taken up : x = amount of 
alkaloid. 

The hydriodic acid, it is supposed by Kippenberger, 
results from the interadlion of iodine and water, 

2l-|-2H20 = 2HI-f-Ha02, 
a readtion which is facilitated or induced by the avidity 
of the alkaloids to form insoluble periodides of the hydrio- 
dides. His reasons for assuming that such a peculiar 
readlion takes place under the simple conditions of pre- 
cipitation are too lengthy to be given here. AH his argu. 
ments rest upon the assumption that all alkaloids form 



^V^^A'^^s^''} Analytical Methods involving the Use of Hydrogen Dioxide, 8i 



periodides of uniform composition, Alk.HI.Iji and that 
the same alkaloid gives always the same periodide. Now, 
there is no reason, d priori, why this should be the case, 
Jorgenson's {yourn. Prakt. Chem., 1870-78, [2], ii., 433, 
&c.) extended researches show that different alkaloids, 
when treated under apparently the same conditions, give 
periodides of entirely different compositions. Thus, 
morphine gives with Wagner's reagent Alk.HI.I3 (Jorgen- 
Bon, 1870, yourn. Prakt. Chem., [2], ii., 438); codeine 
furnishes with excess of Wagner's reagent Alk.HI.I4; 
and caffeine, as will be shown, gives Alk.HI.I4, ^^- ^' '^ 
safe to say that not until we ascertain exadly the com- 
position of the different periodides as produced under the 
conditions of titrations, will the use of Wagner's reagent 
for quantitative purposes be placed upon a sound basfs. 

I have dwelt at such length upon this subje(5t, because 
the method for the estimation of caffeine presently to be 
described, is based upon experimental evidence which is 
entirely contradictory to Kippenberger's conclusions. 
Whatever the cause may be with other alkaloids, his 
theory as to the production of hydriodic acid from iodine 
and water does not hold good in the case of caffeine. 

Wagner, in describing his method, gives a list of alka- 
loids which are completely precipitated by iodine solution, 
and also mentions that " caffeine, theobromine, piperine, 
and urea are not precipitated at all " {loc, cit., 41). His 
statement, so far at least as caffeine is concerned, has 
stood since then uncontradicted. It has found its way 
not only into standard treatises and text-books,* but even 
into periodical literature of recent date. As late as 1894, 
Kunze {Ztschr. Anal. Chem., xxxiii., 23), in reviewing the 
chemistry of caffeine and theobromine, calls attention to 
this peculiarity of the two alkaloids. The non-precipita- 
tion of caffeine by Wagner's reagent has come to be 
recognised as a distinguishing feature of this alkaloid 
from almost all other vegetable bases. 

And yet this is entirely contrary to aCtual fadts. Instead 
of forming an exception, caffeine conforms to all the 
requirements! necessary in the application of this test. 
It is well known that most of the alkaloids as such are 
insoluble, or only very slightly soluble in water; they 
require the presence of some acid for their complete solu- 
tion. In other words, alkaloids in the form of their salts 
are soluble in water. Whenever Wagner's reagent is 
applied for the precipitation of an alkaloid, it is always 
applied to a solution of some salt of it, preferably acidu- 
lated with sulphuric or hydrochloric acid. Therefore, 
even when strictly neutral salts of alkaloids are employed, 
there is still the possibility of the formation of hydriodic 
acid, or rather of the hydriodides of the alkaloid, as, for 
instance, Alk.HCH-KI = Alk.HI-|-KCl. The hydriodide 
thus produced is at once precipitated as a periodide. Now, 
it so happens that caffeine is tolerably soluble in water, 
and it has become customary to work with solutions of 
caffeine as a free alkaloid, and not in the form of its salts. 
The question as to whether solutions of free alkaloids are 
precipitated with Wagner's reagent has not, to my know- 
ledge, been studied. My preliminary experiments in that 
direction show that at least some alkaloids (morphine, 
atropine, strychnine, &c.), are precipitated. I have not 
examined yet whether these periodides are identical in 
composition with those produced from the salts of the 
alkaloids. But so far as caffeine is concerned, it is true 
that a neutral solution of it gives no precipitate when 
treated with a solution of iodine in potassium iodide. 
When, however, the addition of Wagner's reagent is 
either followed or preceded by the addition of some dilute 
acid, there is at once thrown down a dark-reddish pre- 

♦ Prescott," Organic Analysis," p. 80; Allen, "Coram. Organic 
Analysis,'' iii., (2), 481 ; Fluckiger, " Reaflions "(Nagelvoort's Trans- 
lation), p. 26 ; not affed^ed by Wagner's reagent in either neutral or 
acid solutions ; Dragendorff, 1888. Ermittelung von Giften says that 
caffeine gives a dirty-brown precipitate. From the text it is not 
improbable he used iodine in hydriodic acid. 

i This test is perhaps most frequently made in a neutral solution, 
representing, as customary state free caffeine and normal suits of 
other alkaloids. 



cipitate, remaining amorphous even on long standing.* 
The composition of this periodide is, as will be shown, 
C8H10N4O2.HI.I4. It was obtained for analysis in many 
different ways — by using either caffeine or iodine in ex- 
cess, and by employing different acids. The periodide 
produced is, however, always of the same composition. 
The precipitates were allowed to settle, filtered by means 
of a pump, washed with water to remove the excess of 
potassium iodide, dried on porous plates, and finally in a 
vacuum over sulphuric acid. 

(To be continued). 



SOME ANALYTICAL METHODS INVOLVING 

THE USE OF HYDROGEN DIOXIDE.f 

By B. B. ROSS. 

The use of hydrogen peroxide as a laboratory reagent, 
although originally restricted to a few operations of minor 
importance, has within recent years met with a much 
wider extension, and its numerous applications in both 
qualitative and quantitative analysis render it at present 
almost indispensable in every well-equipped analytical 
laboratory. 

Among the more interesting applications of this sub- 
stance in quantitative estimations are those which are 
based on the reaction which takes place when an excess 
of hydrogen dioxide is brought in contact with an acid 
solution of chromic acid, and Baumann {Zeitschr. Anal. 
Chem., xxxi., 436) several years since described quite fully 
a number of analytical processes growing out of the re- 
action referred to. 

In the process for the estimation of chromic acid in 
soluble chromates as outlined by Baumann, the substance 
under examination is first brought into a state of solution, 
and the not too concentrated liquid is transferred to a 
generating flask of special construction. 

Ten c.c. of dilute sulphuric acid are next added, after 
which from 5 to 10 c.c. of commercial hydrogen peroxide 
are run in from a small closed vessel connected with the 
generating flask, while the oxygen which is evolved, after 
the vigorous shaking of the contents of the flask, is col- 
lected over water in an azotometer. 

The following equations given by Baumann illustrate 
the chemical changes connected with the above-described 
reaction : — 

KzCrzOy-f HaOj-f H2S04 = K2S04-f 2H2O -f CrjOy ; 
Cr207-f3H2S04-f4H202 = Cr2(S04)3+7H20-h08. 

From these equations it will be seen that for 2 mole- 
cules of chromic acid, or i molecule of potassium di- 
chromate, there are evolved 8 atoms of oxygen, giving 
an equivalent of 445*3 c.c. of oxygen (measured at 0° C. 
and 760 m.m. pressure) for each grm. of chromic acid 
which may be present. 

The writer, soon after the appearance of the original 
article by Baumann, made a number of experimental 
tests of this method, with a view to applying it to some 
other analytical processes, and still more recently has 
conducted a series of tests for the purpose of determining 
the adaptability of Baumann's method to the indirect 
volumetric estimation of iron. 

In the dichromate method for the volumetric deter- 
mination of iron, as commonly employed, the end-point 

* Almost the same can be said of theobromine, making allowance 
for the difference of solubility of the alkaloid in water. A saturated 
solution of it (containing one part of theobromine to 1600 of water) 
gives no precipitate with Wagner's reagent, but on the addition of a 
drop of acid there separates in a short time a crystalline periodide. 
Contrary to usual statements, 1 find that theobromine in acid solu- 
tions gives a heavy precipitate with Wagner's reagent, of a peculiar 
dirty-blue colour. 

t Read at the Buffalo Meeting, August 22, i8g6. From tbt Joumal 
the American Chemical Society, xviii.i p. gi8. 



82 



Analytical Methods involving the Use of Hydrogen Peroxide, {^Feb!^itS7^*' 



of the oxidation process is ascertained by the readion 
with potassium ferricyanide. 

As the end of this readtion is almost invariably difficult 
to determine, particularly if zinc has been employed as a 
reducing agent, the dichromate process has met with but 
limited application. 

In order to apply the principle of the chromic acid 
method of Baumann to the estimation of iron, an excess 
of dichromate solution was employed in all of the tests 
and experimental determinations, the amount of the 
excess of chromic acid being determined by the volume 
of oxygen evolved upon treatment with hydrogen dioxide. 

The mode of procedure adopted was as follows: — 

A dichromate solution was prepared by dissolving 4*9 rj 
grms. of C. P. crystallised potassium dichromate in water 
and diluting to a bulk of i litre. 

The iron solution employed in standardising the 
dichromate and permanganate solutions was obtained by 
dissolving iron wire in dilute sulphuric acid, the solution 
being reduced with metallic zinc, as usual, previous to 
titration. 

The dichromate solution was also titrated against a 
freshly-prepared solution of ammonium ferrous sulphate, 
the strength of which had been determined by titration 
with permanganate solution, which had also been care- 
fully standardised by means of iron v/ire. 

In order to ascertain the strength of the dichromate 
solution by the hydrogen dioxide method, about 15 c.c. of 
the dichromate solution is run into the generating flask 
above referred to, and there is also added an amount of 
ferric sulphate solution (free from ferrous sulphate) equi- 
valent to about o*o6 to o"io grm. of iron. The objedl of 
employing the ferric sulphate in this standardisation is to 
supply approximately the same conditions as obtain in the 
process for the a<5lual determination of iron. 

The amount of oxygen given off from chromic acid in 
the presence of ferric sulphate is slightly less than that 
evolved when ferric sulphate is absent, but the amount of 
ferric iron present may vary considerably without affedting 
the volume of oxygen liberated. 

To the contents of the generating vessel about 10 c.c. 
of dilute sulphuric acid are now added, and the flask is 
then connected by means of a rubber tube with a Schuize's 
azotometer, which has been filled with water to the zero 
point. 

From 5 to 10 c.c. of hydrogen dioxide are next run in 
from a small closed vessel connedted with the generating 
flask, and the mixed liquid is then shaken, at first gently, 
and afterwards vigorously. The tube leading from the 
flask to the azotometer should be provided with a stop- 
cock, which should be closed before and opened imme- 
diately after each shaking. 

The last trace of the oxygen liberated will not be dis- 
engaged until after the lapse of about five minutes, but it 
is not necessary to continue the shaking during the whole 
of this period. After equalising the height of the water in 
the two tubes of the azotometer, the volume of oxygen is 
noted, and is easily corredled for temperature and pressure 
by reference to proper tables. 

In order to test the strength of the dichromate solution 
by means of iron wire, a given weight of the wire is dis- 
solved in dilute sulphuric acid, the solution reduced with 
zinc, as usual, and rapidly transferred to the generating 
flask (filtering, if necessary). 

An excess of dichromate solution is now run in, hydro- 
gen dioxide is added, and the oxygen is set free and 
colledted as before described. 

If a large excess of dichromate has been used in the 
preliminary test, duplicate tests should be made with em- 
ployment of a small excess, say from 2 to 3 c.c. of the 
dichromate. 

The strength of the solution can then be readily calcu- 
lated by difference, and, if necessary, the results can be 
checked by still further tests. 

In the determination of iron in ores by this process, 
the solutions of ferric iron are reduced by zinc, as in the 



common permanganate method, and the remainder of the 
process is conduded just as described for the standardisa- 
tion of the dichromate by means of iron wire. 

In additit n to numerous tests of solutions of pure iron, 
several estimations of iron in iron ores were made by this 
process, the results obtained being compared with those 
secured by the permanganate method. 

The following are the results of the tests of the iron 
ores referred to : — 



Permanganate method. Dichromate 
Mean of several method, 

determinations. 



Iron ore No. i . . 



Iron ore No. 2 . . 



40*92 



5471 



40-59 
41-25 
5535 
55-43 
55-50 



In the determination of iron in ores by this process, it 
is best, as in the case of the tests with iron wire, to em- 
ploy only a small excess of the dichromate solution, after 
making a preliminary determination, as the results are 
much more accurate with a small than with a large excess 
of chromic acid. 

While a sufficient number of determinations have not 
been made to ascertain the probable value of this method 
as an independent process for the estimation of iron, 
nevertheless some of the results secured would seem to 
warrant the conclusion that it might prove of utility as a 
check method, it being easy of execution and not at all 
time-consuming. 

The following equation represents the changes which 
take place when the dichromate is brought in contadt with 
the iron solution after redudlion : — 

6FeS04-HK2Cr207 4-7H2S04 = 

= 3Fe2(S04)3-hK2S04-fCr2(S04)3-t-7H20. 

The writer has also attempted to apply the principle of 
the chromic acid method above described to the estima- 
tion of invert sugar, or rather to the determination of the 
amount of cuprous oxide thrown down from Fehling's 
solution in the process commonly employed for estimating 
reducing sugars. 

The following equation represents the changes which 
take place when cuprous oxide is brought in contadl 
with potassium dichromate in the presence of dilute sul- 
phuric acid : — 

3Cu20 + K2Cr2074-ioH2S04 = 

= 6CuS04+K2S04+Cr2(S04)3 + ioH20. 

The cuprous oxide thrown down from the sugar sola- 
tion under examination is brought upon an asbestos filter 
connedted with a filter-pump, and thoroughly and rapidly 
washed with hot water. The filter and contents are next 
transferred to the generating flask of the apparatus before 
described, and after the addition of dilute sulphuric acid 
an excess of dichromate is run in. 

Very thorough and long-continued agitation of the 
contents of the flask is necessary in order to efifedt the 
complete oxidation and solution of the cuprous oxide, 
and the hydrogen peroxide must not be added until the 
solution is complete. 

The oxygen liberated on the addition of the hydrogen 
dioxide is colledled, and the volume noted as before 
described. The equivalent amounts of chromic acid, 
cuprous oxide, and invert sugar can be easily calculated 
from the data thus secured. 

This method, while apparently satisfadtory from a theo- 
retical standpoint, has so far failed to give sufficiently 
uniform results, one of the chief objedtions to the process 
being the difficulty attendant upon the solution of the 
cuprous oxide. 

With improvements in the details of manipulation of 
the process, however, it is quite possible that more satis- 
fadtory results could be obtained. 



CbbiJioal Nbws 
Feb. 12, 1897. 



Tutorial Chemistry, 



S? 



NOTICES OF BOOKS. 



The University Tutorial Series, The Tutorial Chemistry. 
Part I.— Non-metals. By G. H. Bailv, D.Sc, Ph.D. 
Heidelberg, Ledlurer on Chemistry in the Vi(5loria Uni- 
versity, Edited by William Briggs, M.A., F.C.S., 
F.R.A.S., Principal of University Correspondence Col- 
lege. London : W. B. Clive, University Correspondence 
College Press. Warehouse, 13, Booksellers Row, 
Strand, W.C. Pp. 226. 
We must confess our partial inability to explain the 
nature or charaderistics of " tutorial chemistry." We 
know that certain Universities, such as, e.g., Oxford and 
Cambridge, call themselves ''tutorial," whilst others, 
such as Munich and Heidelberg, rank as investigational, 
and one at least, that of London, is purely examinational. 
But how any given Science, or modification of a Science, 
can be called tutorial we doubt. From our inspedion of 
the volume before us we should think that tutorial che- 
mistry must approximate closely to examinational 
chemistry, or to the preparatory work required for passing 
examinations. If the Correspondence College facilitates 
the process of " passing," and thus helps to shake public 
faith in the Chinese system of higher education now 
dominant in Britain, it will have done a valuable and 
needful work. 

The author and editor very justly contend that it is 
unwise in the earlier stages to overburden the student 
with chemical theory. They are also, in our opinion, 
right in referring the study of the principles of light, 
heat, and eledtricity to works on physics. 

The leading truths and laws of chemistry are here ex- 
pounded in a most masterly manner ; made, in fadl, 
accessible to very moderate capacities, if only perse- 
veringly and honestly applied to the task. 

There is no attempt to introduce novel matter or to 
initiate the student into research, either of which aim 
would have been distindly outside the plan of the work, 
if not outside the entire scope, of the University Corre- 
spondence College. Within that scope, if we rightly 
apprehend it, a better manual could scarcely be written. 



The Australian Medical Directory and Handbook ; in- 
cluding a Short Account of the Climatic and Sea-side 
Health Resorts in Australia, Tasmania, and New 
Zealand. Edited and Compiled by Ludwig Bruck, 
Fourth Edition, corrected up to September, 1896. 
(Copyright). Sydney: L. Bruck, Medical Publisher. 
London : Bailliere, Tindall, and Cox. i8g6. 
The scope of this useful work is somewhat wider than it 
would appear from the title. It comprehends also Fiji 
and the British portion of New Guinea. We are glad to 
find that the author calmly ignores all the non-qualified 
pradlitioners, who are now so numerous. 

There is an abstract of the Medical Ads of Australia, 
Tasmania, New Zealand, and Fiji. There is a list of the 
medical and allied scientific societies in Australasia. 
Some of them are of high standing, and have done good 
work. Such are, e.g., the Royal and the Linnean Societies 
of New South Wales, the former of which bodies has a 
medical and a microscopical sedtion. The Intercolonial 
Medical Congress of Australasia is an itinerant body after 
the pattern of the British Association. 

The scale of fees legally recoverable by medical men 
are certainly not exorbitant, and, in comparison with the 
wages of mechanics, servants, &c., may be called paltry. 
In the local Medical Diredory for each Colony, the alti- 
tudes to the various towns above sea level are given, 
and a rough view of the racial charader of the popula- 
tion. We are sorry to see to what an extent the 
"heathen Chinee" predominates in some localities. An 
interesting feature is the chapter on health-resorts. Here 
we find given the average rainfall, the extreme and 



average temperatures, and the kind of constitution for 
which they are most adapted. 

At some of the littoral towns sea-bathing is mentioned 
as one of the local attradions or beneficent features. 
The abundance or scarcity of sharks in the sea — a point 
of great importance — is not mentioned. At some places 
a range for bathing is fenced in with iron chains, 



City and Guilds of London Institute for the Advancement 

of Technical Education. Examinations Department. 

Report of the Work of the Department for the Session 

1895-96. Exhibition Road, London, S.W. 1896. 

The adivity of the Examination Department is greater 

and wider than we might exped from its unhappy name. 

It includes the arrangement of courses of instrudion in 

technical subjeds, the consideration of the qualifications 

of teachers. 

A distindion seems to have been made between the 
certificate granted to students who have attended a course 
of lessons at a recognised school and that given to can- 
didates who produce no evidence of such training. The 
results are said to have been very satisfadory. 

The total number of subjeds is 62, but in five of these 
no examinations have adually been held. Of the greatest 
percentage of failures, viz., 76, i per cent was in litho- 
graphy, and the smallest, oo'o, were in the alkali and soap 
manufadure, in the lace manufadure, and in ship 
carpentry. 

At Aylesbury there was one candidate for examination, 
who passed. 



La Unifikazion da las Medidas. Par K. Newman. Val- 
paraiso : Karlos Kabazon. 1897. 
Chili is a perfed focus of reforms, especially ortho- 
graphic. Senhor K. Newman's publications remind us of 
our old friend the Fonetic Nuz. The present objed of 
the author is to advocate the metric system " pure and 
simple." He urges its adoption by all nations in its 
original polysyllabic nomenclature, in preference to the 
more convenient form devised in Holland. 

The names proposed by the French revolutionary com- 
mission may be unobjedionable for wholesale transadions, 
but for the retail business of daily life they have proved 
themselves impradicable. 

We should recommend K. Newman, when advocating 
any reform, to do so in a language " understanded of the 
people," and not bring it in a novel and fantastic ortho- 
graphy. 

MISCELLANEOUS. 

Royal Institution. — A General Monthly Meeting of 
the Members of the Royal Institution was held on 
Feb. ist, Sir James Crichton-Browne, M.D., F.R.S., 
Treasurer and Vice-President, presiding. The following 
were eleded Members :— Mr. Alfred Louis Cohen, Mrs. 
Delaforce, Sir Charles A. Elliott, K.C.S.I., LL.D., Mr. 
John Lawson Johnson, Dr. A. Liebmann, Mr. T. George 
Longstaff, Mr. Howard Marsh, F.R.C.S., the Rev. E. G. 
C. Parr, M.A., Mr. Charles Rose, and Mr. Edward P. 
Thompson. The special thanks of the Members were 
returned to Sir Frederick Abel, Bart., K.C.B., for a 
donation of^^so, and to Mr. J. Wolfe Barry, C.B., for a 
donation oi ^25 to the fund for the pronwiion of Experi- 
mental Research at Low Temperatures. 

NOTES AND QUERIES, ~ 

♦** Our Notes and Queries column was opened for the purpose of 
giving and obtaining information liltely to be of use to our readers 
generally. We cannot undertake to let this column be the means 
of transmitting merely private information, or such trade notices 
as should legitimately come in the advertisement columns. 
Epsom Salts.— A correspondent asks whether Epsom salts are 

best reduced to the state of a dry powder by hot cylinders or in an 

oven, and then rolling in a mill. 



84 



Meetings /or the Week. 



( Chbuical Nbws, 
I Feb. 12, 1897. 



MEETINGS FOR THE WEEK. 

Monday, 15th.— Society of Arts, 8. (Cantor Leftures). "Industrial 
Uses of Cellulose," by C. F. Cross, F.C.S. 

Society of Chemical Industry, 8. Adjourned Dis- 

cussion on Mr. W. J. Dibdin's Paper on " The 
Character of the London Water Supply." 
Tuesday, i6th.— Royal Institution, 3. " Animal EleiSricity," by 
Prof. A. D. Waller, F.R.S. 

Society of Arts, 8. " The Progress of Canada during 

the past Sixty Years of Her Majesty's Reign," 
by Joseph G. Colmer, C.M.G. 
Wednesday, 17th.— Society of Arts, 8. " Light Railways," by Ever- 

ard R. Caltbrop. 
Thursday,' iSth.— Royal Institution, 3. " The Problems of Ardtic 
Geology," by J. W. Gregory, D.Sc, F.R.S. 
—^ Chemical, 8. " The Oxidation of Sulphurous Acid 

by Potassium Permanganate," by T. S. Dymond 
and F. Hughes. " Sodamide and some of its 
Substitution Derivatives," and " Rubidamide," 
I by A. W. Titherley. M.Sc, Ph.D. 
— — Society of Arts, 8. " The Mechanical Production 

of Cold," by Prof. James A. Ewing, M.A., F.R.S. 
Friday, 19th.— Royal Institution, 9. •' The Approaching Return of 
the Great Swarm of November Meteors," by G. 
Johnstone Stoney, M.A., F.R.S. 
Saturday, zoih. — Royal Institution, 3. " The Growth ot the 
Mediterranean Route to the East," by Wa Iter 
Frewen Loid. 



TO CORRESPONDENTS. 

R. G, B. — We do not think any notice of the mentioned patents 
has yet appeared. 

C. Stanley.— Tht responsibility of advising in such a case is more 
than we care to take. 

A. S. Chase. — Consult " Explosives and Their Powers," by Col. J. 
P. Cundill," and " A Handbook of Modern Explosives," by M. Eiss- 



CIVIL SERVICE COMMISSION. 
FORTHCOMING EXAMINATION. 

Second Assistant to the Ledlureron Eledlricity 
at the ARTILLERY COLLEGE (20-25), 24th February. 
Technical training and qualifications necessary. 

The date specified is the latest at which applications can be re- 
ceived. They must be made on forms to be obtained, with particulars, 
from the Secretary, Civil Service Commission, London, S.W. 



T aboratory Attendant required in 

-L ' Medicine Laboratory. Wages.iss.— Apply to 1 



KING'S COLLEGE, LONDON. 

in the State 

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ment. Moderate Salary.— Address, " Plant," Chemical News Office, 
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JUST PUBLISHED. Crown 8vo., cloth, 65. 

TABLES for the QUANTITATIVE 

ESTIMATION OF THE SUGARS. 

With Explanatory Notes. By Dr ERNEST WEIN. 

Translated, with additions, by WILLIAM FREW, Ph.D. (Munich), 
Wellpark Brewery, Glasgow. 

London: E. & F. N, SPON, Ltd., 125, Strand. 



Recently Published, with Illustrations, in Demy 8vo., cloth. 

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Miller, Ph.D., Manchester, and Revised by the Author. 

London: E. & F. N. SPON, Ltd., 125, Strand. 



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-«»^«^AL NBw», ., }Jq^ Soon shall Students begin the Study <>f Qualitattve A nalysis. 



85 



THE CHEMICAL NEWS 



Vol. LXXV., No. 1943. 



HOW SOON SHALL THE STUDENT BEGIN 

THE STUDY OF QUALITATIVE ANALYSIS ? 

By ALFRED C. BEEBE. 

In the following paper I shall attempt to show at what 
8tat»e of laboratory work the student can most advanta- 
geously be introduced to the study of qualitative analysis. 

To the teachers who begin the laboratory course with 
qualitative analysis I have nothing to say. But to the 
teachers who require the student to devote all, or a large 
part, of the first months in the laboratory to the study 
of the preparation and properties of the non-metallic 
elements, I wish to present some arguments for replacing 
that department of the subjed by the study of qualitative 
analysis. 

I have three objedlions to requiring the student 
beginning laboratory work to perform experiments relating 
to the non-metallic elements. First, the experiments are 
more or less dangerous. Second, the student nearly 
always fails to connedl the different experiments with 
each other. Third, the work does not awaken and hold 
the student's interest as well as qualitative analysis does. 
Of course, the student must have a good knowledge of 
the properties and preparation of the non-metallic 
elements, but it seems to me this is best gained from 
leftures, illustrated by the proper experiments given by 
the teacher before the entire class. I wish to say that I 
think this part of the subjedt is often made so unneces- 
sarily complex that the student's ideas of it are very con- 
fused and hazy. Let the first ideas of chemistry, both in 
the leifture room and the laboratory, be as simple as the 
subjedl will permit. The details are easy enough to learn 
afterwards if they be necessary. 

Let me consider at greater length the three objedions 
made above to the study in the laboratory of the non- 
metallic elements by the beginner. 

First : Danger. A university professor said to me 
recently, " I always dread hydrogen day ; I am nervous 
every minute the students are working with this dangerous 
gas, for I feel as if a serious explosion migiit occur at any 
time when students have as little experience as the 
beginner possesses." This state of mind is, I believe, not 
uncommon among teachers who require their students 
to experiment with hydrogen soon after beginning the 
laboratory work. I feel sure that almost every teacher 
knows of several serious explosions with hydrogen, and 
of many more that might have been serious except for 
good luck. Considering these fads it seems to me 
unwise to expose the student to this unnecessary danger, 
for no amount of chemical knowledge can repay a pupil 
for the loss of his eyesight. The danger is, however, 
much lessened by some months' experience in the labora- 
tory, and then explosive gases may be given to the pupils 
should the teacher think fit to do so. The preparation 
of oxygen is attended with more or less danger, and I 
know of several serious accidents from this cause. Phos- 
phorus is not a substance to trust a beginner with, and 
yet I know some widely used text-books which give this 
dangerous substance to the pupil soon after his entrance 
to the laboratory. One text-book even goes so far as to 
give work with the iodide of nitrogen ! 

The handling of acids, the use of chlorine, bromine, &c., 
make trouble enough without adding work on explosive 
gases like hydrogen, or work with dangerous substances 
like phosphorus. 



Qualitative analysis, on the other hand, has no experi> 
ments that are even moderately dangerous. Of course, 
dangerous experiments may be included in the branch of 
the subjedl, but they are unnecessary, while for the non- 
metallic elements they form an essential part of the 
course. 

Second: Unconnedledness. Although the experiments 
on the non-metallic elements are connedled it is very 
difficult, in mv experience, to make the student see that 
connedlion. For instance, after oxygen is experimented 
with no further work on that subje(5t is required, and the 
teacher must be continually asking review questions if 
the subjed is to remain fresh in the student's mind. After 
several weeks' experimenting has been done, the amount 
of back work becomes too large for the teacher to review, 
and as the experiments do not require repetition, those on 
one element seem to have almost no connexion with 
those on other elements. I have taken some trouble to 
look into this matter, and have heard so many students 
complain about it, that I consider it an important point. 
Qualitative analysis, on the other hand, requires that 
experiments once learned be remembered, for the future 
work uses them repeatedly, since each day's work in a 
good text-book on this subjed is closely related to what 
has gone before and what is to follow. This fad and the 
repetition necessary while analysing unknown substances 
oblige the student to remember his work, and he goes out 
of the laboratory with a scheme for analysis contaming 
fads as valuable as those relating to the non-metallic 
elements, fixed with reasonable firmness in his mind, 
instead of a confused mass of material such as the work 
on the non-metallic elements too often leaves. Even 
reasonable repetition will not fix seemingly unconneded 
fads, while conneded phenomena almost fix themselves 
in the mind. 

Third : Interest. In no part of th^work in the chemical 
laboratory is so much interest sho#n as in the analysis 
of unknown solutions and substances. This one fad 
would, to me, be sufficient argument for the use of quali- 
tative analysis for the student's first laboratory work. It 
were a waste of words for me to say that we should 
endeavour to awaken and sustain the student's interest in 
a subjed as much as possible, for every teacher knows 
how smoothly and advantageously things run when a 
s^enuine interest is taken in any sort of work or study. 
From my experience, as student and teacher, I feel per- 
fedly confident that qualitative analysis is much more 
fitted to do this than the study of the non-metallic 
elements. The student feels he is a real chemist as soon 
as he analyses his first " unknown solution." Be that 
solution ever so simple he realises that he has acquired a 
new power, and in most cases he becomes anxious to 
increase it. This feeling of independence is helped if no 
results to experiments are given in his text-book, for he 
thereby becomes an original investigator, and not merely 
a student who is required to perform certain experiments 
which shall agree with his text-book. This attitude 
sharpens the observing and reasoning faculties immensely. 
The interest shown in qualitative analysis is oftentimes 
amazing. For example, I have often seen the majority 
of a university class work from four to six hours extra a 
week simply from interest in this branch of the subjed. 
I know of one teacher whose student became so interested 
in qualitative analysis, that in self-defence he had to 
refuse to remain in the laboratory more than two hours 
after the regular hour for closing had come. This last 
happened in a public high school, with a class of boys 
and girls averaging sixteen years old, where we surely ought 
to find average work. Some of this interest maybe due to 
the teachers, but from the fad that it is not an uncommon 
experience, I am inclined to think that much of it is due 
to the fascination of qualitative analysis. I have never 
seen any such results from the study of the non metallic 
elements. 

Summing up the advantages of the study of qualitative 
analysis for the beginner, when compared with the study 



66 



Viscose and Vtscoid. 



of the non-metallic elements, I think I may say that the 
former is less dangerous, more connected, and holds the 
student's interest much better. 
Savanna, 111. 



VISCOSE AND VISCOID.* 

By CLAYTON BEADLE. 
(Concluded from p. 75). 

Production of Viscoid. 

For Use in Turning, Syc. — Viscoid is prepared by coagu- 
lating the viscose in the same way as described above for 
the produ&ion of veneers or sheets, but the moulds are 
circular instead of redtangular. As might well be sup- 
posed, the difficulties of coagulating the viscose increase 
with the diameter of the cylinder. Great care has to be 
taken in the early stages to prevent the material from 
cracking. Immediately after coagulation takes place there 
is a considerable shrinkage, and unless the coagulation 
proceeds uniformly throughout the mass there is danger 
of it cracking. The time of coagulation increases with 
the diameter. The moulds in which the material is 
coagulated are specially construAed, and made of a ma- 
terial which is unaifedled by the viscose, and the interior 
surface has to be such that the coagulum does not adhere 
to it, otherwise it is sure to crack on shrinking. After 
setting, the solid cylinders of coagulum are removed from 
their moulds. At this stage they are elastic and pliable, 
somewhat like rubber, but have to be handled with great 
care. They consist of about 15 per cent of cellulose, 
7 per cent of chemical by-produi^s, and 78 per cent of 
water of hydration. 

Washing. — They are next placed in water for the re- 
moval of the by-produds. We have done much work to 
determine the best conditions, and the cheapest and most 
eifedtive method for getting rid of the by-products. 

When the cylinders of coagulum are placed vertically 
in tanks provided with false perforated bottoms and 
immersed in water, the by-produdls are found to diffuse 
out and creep down the sides of the coagulum and to 
accumulate in the space below the false bottom. This 
adtion is so perfedt that often, when the water is undis- 
turbed, the top portion contains only a trace of by- 
produdls and the lower portion is heavily charged with 
them. The removal of by-produdts is accelerated by the 
use of hot water. We find that the time required for the 
removal of the by-produds varies as the square of the 
diameter of the coagulum. During washing the coagulum 
undergoes a further shrinkage, so that when the washing 
is complete the coagulum contains about 20 per cent of 
cellulose. 

Drying. — The washed coagulum is next removed from 
the tanks and dehydrated or dried. The dehydration of 
the coagulum has presented us with some very interesting 
problems, which we have to a large extent solved. When 
the washed material is exposed to the air, it gradually 
contradls and loses weight, and this goes on until it is 
finally deprived of moisture, and nothing is left but the 
dry viscoid. We found it difficult to ensure that the 
material should retain its proper shape on drying. With 
"rack" or air drying at from 90° to 110° F., a solid 
cylinder remains flat at the ends, provided that the length 
is four times that of the diameter. If it is less than this 
it has a tendency to become concave on the ends, and it 
becomes more concave up to a certain point as the length 
diminishes in proportion to the diameter. The sides of a 
solid cylinder have a tendency sometimes to become con- 
vex in proportion as the ends become concave. Unless 
drying is uniform, a cylinder of ij inches diameter, and 
less, will bend less towards the driest s-ide. With larger 
cylinders this is not so noticeable. When cylinders are 

♦ Journal of the Franklin Institute, January, 1897. 



f Chbuical Nbws, 
I Feb. 19, 1897. 

placed upon a rack that is not perforated, the top end 
contradis and dries the most rapidly, so that the cylinder 
becomes tapered towards the top. When the rack is per- 
forated so as to allow of the free passage of air, the 
cylinder is sometimes found to be smallest at the bottom. 
Sometimes the cylinders are irregular in diameter or 
warped in final drying. During the process of drying 
the coagulum is in a semi-plastic state, and when the 
drying is uneven is under considerable stress. The vis- 
coid is caused to flow in the diredtion to relieve the 
stress, so that, when finally dried and rigid, it is found to 
have assumed its original shape. It generally, however, 
leaves some marks of its temporary distortion. The time 
of drying, so far as our determinations hare gone, varies 
as the square of its diameter. 

When hot air is used the rate of drying cannot be in- 
creased beyond a certain degree without serious injury to 
the solid. The solid, by constant exposure to hot air, 
becomes skin-dried, whilst the interior remains compara- 
tively moist. The outer dried skin offers a great 
resistance to the passage of further moisture, and so the 
drying is very much retarded. If, under these conditions, 
the moisture is able to escape from the interior, the 
exterior — being dry and consequently rigid— offers great 
resistance to the contradlion of the interior, and the con- 
sequence is that fradure often takes place. If the drying 
be not quite so rapid as to produce fradlure, the interior 
is under tremendous stress, and, when the cylinder is cut 
in sedlion, cleavage often takes place in the diredlion of 
the length of the cylinder. When, however, the drying is 
condudled much slower, the moisture— which is always 
tending to pass from the wetter to the drier portions — 
finds a way of escape, and is removed from the surface 
by the atmosphere. We have been able to overcome 
these difficulties, and the produdi obtained is almost free 
from strudture. The washed or unwashed coagulum has 
a natural inclination to contradl when surrounded by a 
hot medium, even when the same has no drying capacity 
whatever. The rate of contradtion increases with the 
temperature ; thus, a coagulum containing 10 per cent 
of cellulose will rapidly contradt to about half its bulk on 
immersion in boiling water. When heated in this way 
there is no indication of case hardening. There is a 
limit, however, to this contradlion. We tried the effedt 
of saturated steam at different pressures upon cylinders of 
washed coagulum, which contained about 15 per cent of 
cellulose. The pressure was varied from 3 to 8 atmo- 
spheres ; the time of exposure was one hour in each case. 
The average contradtion was about 25 per cent. The 
experiments go to show that there is little or no difference 
between the 3 atmospheres or 8 atmospheres on the 
amount of contradtion. As the diameter increases the 
rate of contradlion diminishes. The next set of trials 
were made to determine what effedl time had upon the 
shrinkage in an atmosphere of saturated steam at 4 atmo- 
spheres. Taking the original weight as loo, after one 
hour's treatment, the weight became 82-9. 

After two hours, the weight became 74*5 
» three „ „ „ 657 

.. four „ „ „ 63-0. 

The above was on a piece of washed coagulum, con- 
taining about 15 per cent of cellulose. We next took 
some unwashed coagulum, containing about n per cent 
of cellulose, and suspended it in an atmosphere of satu- 
rated steam at 4 atmospheres. It lost 44*8 per cent 
during the first hour, 147 during the second hour; there- 
fore it had contradled during the two hours' treatment to 
40-5 per cent of its original weight. A receptacle was 
placed immediately beneath the coagulum to catch the 
by.produdts, which were found to be recovered without 
dilution. With blocks of double the diameter of the 
above, ». «.,75m.m., the weight after two hours' treat- 
ment was 56-6 per cent of the original. The effedl of 
saturated steam is to produce a rapid contradlion of the 
coagulum, if it contains from lo to 15 per cent of cellulose, 



Cbbmical Nbws, I 
Feb. 19, 1897. I 



Vtscose and Viscoid, 



87 



and this contraction is rapid until a concentration of about 
20 per cent of cellulose is reached. By a prolonged 
treatment in saturated steam the coagulum gradually con- 
tradls until it contains about 25 per cent of cellulose, 
beyond which point it does not alter. 

Ivory coloured Viscoid. 

Ordinary viscose has about the colour and consistency 
of molasses, and yields a viscoid which has the general 
appearance of horn. We set to work to produce viscoid 
in imitation of ivory, and whilst doing this we discovered 
a new combination of viscose, which gave rise to a creamy 
white solution. This was found to last longer in the 
liquid form than the ordinary viscose. On drying down 
it yielded a produd which is a very fair substitute for 
ivory. It has a specific gravity of i8 to i"85. We had 
several sets of billiard balls turned from this, and they 
were found to play very well indeed. The angle, how- 
ever, at which the balls left each other after striking was 
somewhat less than that of ivory balls. With the plain 
viscoid balls, which have a sp. gr. of 15, the angle is 
greater than that of ivory, and we believe it possible to 
mix these two compositions in such a way that both the 
specific gravity and the angle at which they leave 
each other after striking resemble that of ivory. This 
" ivory " viscoid has been used for various articles, such 
as acorns for blind-cords, knife-handles, brush-backs, &c. 

Viscoid for Electrical Work, — The plain viscoid was 
carefully tested to determine its insulating properties. It 
is about equal to vulcanised fibre for insulating purposes. 
It appears that if great care is taken to thoroughly 
remove the last traces of by-produds, and to well season 
the viscoid, the insulating properties can be made much 
superior to vulcanised fibre. Cellulose, when completely 
deprived of moisture, is almost a perfei^ insulator, and its 
insulation diminishes as the hygroscopic moisture in- 
creases. Viscoid will probably replace vulcanised fibre 
to a large extent for eledtrical work, but at present it is 
very much inferior to vulcanite. It is likely that we shall 
find some means of improving it, so that it may be made 
to replace that substance. 

Black Viscoid, — We next set to work to prepare an 
ebony-black viscoid, and after about six months' work we 
have obtained a uniform black viscoid, which in some 
respedts appears to be superior to the plain substance. 
The ebony viscoid will probably have a greater range of 
utility than any of the other produds we have obtained. 
A jet-black is preferable to white or any colour for 
machine-tool handles, &c. 

Blue Viscoid, — We have obtained a somewhat more 
expensive produ(5l, very much resembling lapis laxuli. 
This is very nice for turning and carving, and takes a 
very high polish, and looks very well when made into 
fancy articles, such as umbrella and walking • stick 
handles. 

Various Colours. — We have now got viscoid in a large 
variety of colours and shades, and have also succeeded 
in producing grained and mottled efiedls, which have a 
very pretty appearance when turned and polished. We 
see no reason why viscoid should not be used in place of 
celluloid for many purposes. Some samples have been 
kept two or three years, and they do not discolour. 
Keeping the viscoid for a long time appears rather to 
improve it than otherwise. 

Paper Sizing, 
Mr. Little mentioned this application of viscose in his 
paper (^jfournal of the Franklin Institute, cxxxviii., No. 
824). Viscose is now being extensively used in paper- 
mills for this purpose. It does not size the paper in the 
sense that rosin does, although when viscose is used a 
large proportion of the rosin can be dispensed with. It 
is added to the beater, and a chemical substance is after- 
wards added which precipitates the cellulose among the 
fibres as a flocculent mass. The effedl that it has upon 
the paper is, of course, dependent upon the amount used. 



It strengthens the paper from 30 to 100 per cent, and the 
paper produced with viscose, besides being much stronger, 
is also harder, has a better " feel " and rattle, and admits 
of a much better surface when calendered. It also assists 
in the retention of clay, and prevents the loss of short 
fibres which, as a rule, pass through the wire cloth of the 
machine. It therefore gives a larger output to the 
machine. It is chiefly used in the manufadure of 
" wrappings " and bag papers, but it is coming into use 
also for news and other papers. Where additional 
strength is not required, it enables the paper-maker to 
use a lower-class and weaker fibrous material, without 
prejudicing either the strength or quality of his paper. 
By this means it decreases the cost of producftion. The 
precipitation of the cellulose requires a great deal of 
skill. Unless care is taken to ensure the right conditions, 
and to add the precipitating agents in the right propor- 
tions, the cellulose is precipitated as a non-adhesive mass, 
which gives neither strength nor hardness to the paper. 
It is necessary to know exadlly the conditions of working 
in each mill before good results can be ensured, but when 
once these are known and understood there is no difficulty 
in obtaining uniform results. 

The Nature of Hygroscopic Moisture in Cellulose, 
The behaviour of viscoid on drying in the mass opened 
up some very interesting problems. It appeared to throw 
light upon the hygroscopic moisture of celluloses. I had 
previously observed {Nature, xlix.. No. 457) that the 
cotton fibre, when deprived of moisture (either by drying 
in an air-bath at 105° C, or in a desiccator over sulphuric 
acid) and exposed to the air, rose in temperature rapidly 
for about eight minutes. It reached a temperature of 
about 4i° F. above that of the atmosphere, where it 
remained nearly stationary for a few minutes. It then 
fell gradually, and after about seventy minutes' exposure 
it again reached the temperature of the surrounding atmo- 
sphere. I endeavoured to find what connexion this had 
with the rate at which bone-dry cotton fibre assumed its 
hygroscopic moisture. I found that cotton fibre took 
about seventy minutes, and, by weighing the cotton at 
different intervals, and comparing the rate of gain in 
weight with the rate of increase in temperature, I was 
led to the conclusion that the two were closely connecfted. 
The same experiments were repeated with anhydrous 
viscoid which had been ground to a powder before drying. 
The viscoid first of all suddenly fell below the temperature 
of the atmosphere. It fell much slower than the cotton 
fibre, and even at the end of 160 minutes' exposure it was 
still about 3° above the atmospheric temperature. At 
this point it had only recovered about 90 per cent of its 
hygroscopic moisture, and it only came to a constant 
weight after about 210 minutes' exposure. By grinding 
viscoid to a much finer powder than was used for the 
above, and repeating the experiments, a much more 
regular curve was obtained, and the hygroscopic mois.ure 
was very much diminished ; but the time required for the 
material to fall to the temperature of the atmosphere was 
not lessened. I took some cotton-wool which I ground 
to a fine powder, and I found that, although it took about 
sixty minutes to recover its hygroscopic moisture, it con- 
tained only about 4 per cent instead of 7 per cent 
moisture. All these experiments were repeated with 
similar results. From this it is evident that the hygro- 
scopic moisture of a cellulose, whether amorphous or in 
the fibrous condition, is dependent not only upon the 
charaifter of the cellulose itself, but also upon the extent 
to which the cellulose is disintegrated. This is contrary 
to accepted views on the subject. It is only when parti- 
cles of viscoid are below a certain size that the hygro- 
scopic moisture is materially diminished. It appears 
that the cellulose that composes the cell-walls of the 
ultimate fibre is under certain stress when deprived of 
moisture, in the same way that lumps of viscoid are 
when they are dried, and that the amount of stress deter- 
mines the amount of moisture that it will take up to 



88 



Rtport of Commiitee on Atomic Weights. 



CllbailCAL Nbws, 

^ Feb. 19, 1897. 



relieve the stress. Cellulose expands when hydrated, 
and it appears that the hygroscopic moisture is really 
water of hydration of the cellulose, and that it tends to 
hydrate in proportion to the stress that exists in the 
anhydrous cellulose. This accounts for the fadt that the 
smaller particles of viscoid contain less hygroscopic 
moisture than the larger; also, which is more marked, 
disintegrated cotton fibre contains much less hygroscopic 
moisture than when the fibre is left intadl. I have 
prepared small particles of viscoid, which, when bont 
dry, would fly to pieces on being scratched, like " Prince 
Rupert Drops; " but tlie same particles, on being placed 
in a damp atmosphere, swell somewhat and recover their 
strength. 

Particles can, on the other hand, be prepared in such 
a way that they do not exhibit brittleness, and they 
expand to a much less degree on being placed in a moist 
atmosphere. The results all tend to the same conclu 
sion, in my mind, as to the nature of hygroscopic moisture 
in cellulose. 



THIRD ANNUAL REPORT OF COMMITTEE 

ON ATOMIC WEIGHTS. 

RESULTS PUBLISHED DURING 1895.* 

By F. W. CLARKE. 

(Ooutinued from p. 76). 

Cobalt. — The atomic weight of cobalt has been re- 
determined by Thiele (" Die Atomgewichts bestimmung 
des Kobalts," a doctoral dissertation, Basel, 1895). First, 
carefully purified oxide of cobalt, CoO, was reduced in 
hydrogen. The weight and results are as follows : — 

Residual Co. Loss of O. Atomic weight of Co. 

0-90068 , 0-24429 58-843 

079159 0-21445 58-912 

1-31558 0-35716 58-788 

Mean 58-848 

Reduced to vacuum standards this becomes — 
Co = 58-826, 
when O = 1596. 

In a second method metallic cobalt was dissolved in 
hydrochloric acid, and the solution evaporated to dryness 
with special precautions against dust. The chloride thus 
obtained was then dried at 150" in a stream of pure 
gaseous hydrochloric acid, so that basic salts could not 
be formed. F"^riim the weight of cobalt and of cobalt 
chloride the ratio Co: Cla is determined. The chlorine 
was afterwards re-estimated as silver chloride, giving liie 
ratio Co : 2AgCl. The weights are subjoined : — 
Co taken. CI taken up. AgCl. 

0-7010 0-8453 — 

0-3138 0-3793 — 

0-2949 0-3562 1*4340 

0-4691 0-5657 2-2812 

0-5818 0-7026 2-8303 

0-5763 0-6947 — 

0-5096 0-6142 2-4813 

Hence, with Cl = 35-37, and Ag = i07 66, Co = 
Co : Clj. Co : 2AgCl. 

5866 — 

5852 — 

5857 58-828 

5866 58-825 

5852 58803 
58-68 — 

58 69 58*750 



Mean 58 64 



Mean 58801 



♦ Kcaii at the Clevtlaud Mteiaig, DecciLbtr 31, royj. 
Journal of the American Chemical Society, xviii.. No. 3. 



The second column is subje<ft to a small conevSlion for 
dissolved silver chloride, which reduces the mean to 
00 = 58770. Reduced to a vacuum this becomes 58-765, 
and the value from the Co : CI2 ratio becomes 58*61. 
Thiele regards 00 = 58 765 as the most probable value to 
be derived from his experiments. This becomes — 
With = 16 00 = 58-912 

,, = 15-88 00 = 58-470 

In my report for 1894 I gave Winkler's work on cobalt 
and nickel, which iiivolved their ratios to iodine. In a 
supplementary paper Winkler [Ztschr. Anorg. Chem., viii., 
291) gives some similar experiments with iron, intended 
to show that errors due to metallic occlusion of hydrogen 
are absent from his determinations. He succeeds in 
proving that such errors, if they exist, must be very small. 
Thiele also considered their possibility, and guarded 
against them in the preparation of his cobalt. 

Zinc. — Atomic weights re-determined by Richards and 
Rollers (Ztschr. Anorg. Chem., x., i ; calculations made 
with 0=i6, Ag=io7 93, and Br = 79-955), who used the 
bromide method. Zinc bromide, carefully purified, was 
ireated gravimetrically with standard silver solution. The 
weights and results are subjoined : — 

First, ZnBra : 2AgBr. 

ZaBr,^. AgBr. Atomic weight of Zn. 

1-69616 282805 65-469 

1-98x98 3*30450 65-470 

170920 284549 65-487 

235079 391941 65-470 

2-66078 443751 65400 





Mean.. 


65459 




Second, same ratio. 




ZnBrj. 


AgBr. Atom 


ic weight of Zn 


2-33882 
1-97142 
2-14985 
2-00966 


3 90067 
3*28742 
358539 
3*35074 


65-400 

65*434 
65-402 

65463 




Mean.. 


65*425 




Third, ZnBr^ : Agz. 




ZnBrj. 


Ag. Atoir 


ic weight of Zn 


2 33882 
1-97142 
2-14985 
2-00966 


2-24063 
1-88837 
205971 
1-92476 


65-409 

65*444 
65-396 
65*472 



Mean.. .. 65-430 

Two additional series of data are given by Richards 
alone, as follows : — 

Fust, ZnBrj : Ai-j. 

ZnBrj. Ag. Atomic weight of Zn. 

6-23833 5-9766 65-403 

5*26449 5*0436 65-404 

9-36283 8-9702 65-392 



ZnBr^. 
2 65 847 
2-30939 
5*26449 



Mean.. .. 65-402 
Second, ZnBrj: 2AgBr. 

AgBr. Atomic weight of Zn. 

443358 65-410 

3-85149 65-404 

8-77992 65-404 



Mean.. 



65-406 

The final mean adopted by Richards is 65-404. With 
= 15-88 this becomes — 

Zn = 64-913. 
Cadmium. — Mr. Buchei's paper,* as iis title indicates, 



* •• An Examiiiaiioii of some Methods Employed in Determining 
the Atomic Weight of Cadmium," by Jjhu E. Biichtr. Johns 
Hiipkms University doctoral dissertation. Baltimore (Friedenwald), 
1895. 



CBBMICAL MBWS, I 

Feb. 19, 1897. I 



Report of Commtttee on A tomtc Weights, 



89 



is a study of methods rather than a final determination of 
atomic weight ; but the results recorded in it compare 
well with those reached by others. His starting-point is 
metallic cadmium, purified by nine distillations in vacuo, 
and from this material, with pure reagents, his various 
preparations were made. Vacuum weights are given, and 
the antecedent values used in calculation are O, 16 ; S, 
32-059 ; C, 12-003 ; CI, 35-45 ; Br. 79-95 ; and Ag, 107-93. 
First, cadmium oxalate, dried for fifty hours at 150 , 
was decomposed by heat, and so reduced to oxide. The 
variations are mainly attributed to imperfed dehydration 
of the oxalate. Weights and results are as follows : — 



Oxalate. 
1-97674 
I -94912 
1-97686 
1-87099 
i"3755o 
i*333i3 
1-94450 
2*01846 



Oxide. 
1-26474 
1-24682 
1-25886 
1-19675 
0-87994 
0-85308 
1-24452 
I-29210 



Atomic weight of Cd. 
III-74 
111-83 
111-85 
III-81 
11 1-86 
111-96 
112-02 
112*09 



Mean.. .. 111-89 

Second, cadmium oxalate was transformed to sulphide 
by heating in a stream of hydrogen sulphide. The data 

are : — 

Oxalate. Sulphide. Atomic weight of Cd. 

2*56319 1*84716 II2'25 

2-18364 1*57341 iiTig 

2-11643 1-52462 112-03 

3-13105 225582 112-12 



Mean.. 



112-15 



Third, cadmium chloride, dried at 300° in a stream of 
dry, gaseous hydrochloric acid, was precipitated by silver 
nitrate, and the silver chloride was colleifted with all 
necessary precautions. The weights and results are sub- 
joined : — 

CdCI,. 

3-09183 

2-26100 

1*35729 

2*05582 

1*89774 

3*50367 

2*70292 

4-24276 

3-40200 

4-60659 

2*40832 

2*19144 

2*84628 

2-56748 

2*31003 

1-25008 

1*96015 

2*29787 

1-94227 

I -10976 

1*63080 



AgCl, 

4-83856 

3-53854 
2-12431 

321727 
2-97041 

5-48473 
4-23087 
6-63598 

5-32314 
7-20386 

3-76715 
3*42724 

4-45477 
4*01651 
3-61370 
1-95652 
3-06541 

3-59391 
303811 

1-73547 
2-55016 

Mean.. .. 112*39 

Fourth, cadmium bromide was analysed in much the 
same way as the chloride. The weights and results are 
as follows : — 



Atomic weight of Cd. 
112-34 
112-33 
112-32 
112-34 
112-31 
112-28 
112-30 
112-44 
112-37 
112*47 
112-42 
112-46 
112-32 
112*41 
112-41 
112-32 
112-47 
112-45 
112-42 
112-47 
112-48 



CdBr,, 


AgBr. 


Atomic weight of Cd 


4-3994 1 


6-07204 


112 35 


3-18030 


4-38831 


112-42 


3-60336 


4-97150 


112-45 


4*04240 


5-58062 


112-29 


3-60505 


4-97519 


112-38 



Fifth, cadmium sulphate was formed by synthesis from 
metallic cadmium. 1-15781 grms. cadmium gave 2-14776 
cadmium sulphate. Hence Cd = 112-35. As any impurity 
in the sulphate would tend to lower the atomic weight 
found, this is probably a minimum value. 

Sixth, metallic cadmium was converted into oxide by 
solution in nitric acid and ignition of the nitrate. The 
ignition was performed in double crucibles, both porce- 
lain in Experiments 1 and 2, the inner one of platinum in 
the rest of the series. Weights and results as follows : — 



Cd. 
1-26142 
0-99785 



1-11321 
1-02412 
2*80966 



CdO. 
1*44144 
1-40135 



Atomic weight of Cd. 
112-12 
112*04 



Mean.. 



1*27247 

i'«7054 
3*21152 



Mean.. 



112*08 

111*84 
111*91 
ixi'87 

111*87 



Mean.. 



112-38 



In this case additional experiments were made to dis- 
cover the sources of error, leading to corredions which 
bring the results near to those found in the chloride and 
bromide series. Each of the methods is quite fully dis- 
cussed, and the sources of error are noted. With = i6, 
112-39 seems to be a close approximation to the true 
atomic weight of cadmium. 

Molybdenum. — Seubert and Pollard {Ztschr. Anorg. 
Chem., viii., 434; calculations on the basis of Oa-15-96), 
by two distin(a methods, have re-determined the atomic 
weight of this element. First, molybdenum trioxide was 
dissolved, in weighed quantities, in a standard solution of 
caustic soda. The excess of soda was then measured by 
titration with standard sulphuric acid and lime water. In 
another set of experiments the volumetric value of the 
caustic soda had been estimated with standard hydro- 
chloric acid, while the last compound had also been 
determined gravimetrically in terms of silver chloride. 
Hence the data, all considered together, give from their 
true end terms, the ratio M0O3 : 2AgCl, although in a 
very indiredt manner ; and for this indirection the 
authors give good reasons. The weights and results, 
considering only the end terms, are as follows : — 



MoO,. 
3-6002 
3-5925 
373" 
3*8668 
3-9361 
3*8986 
3-9630 
3-9554 
39147 
3-8543 
3-9367 



AgCl. 
7-1709 
7-1569 

7-4304 
7-7011 
7*8407 
77649 
7-8941 
7-8806 
7-7999 
7-6767 
7-8437 



Atomic weight of Mo. 

95-734 
95-708 

95757 
95-749 
95-720 
95-740 
95-723 
95-694 
95-686 

95-740 
95-688 



Mean.. 



95-722 



Reduced to vacuum standards this becomes Mo=95-729. 
With = 16, Mo = 95-969; and with = 15-88, Mo= 
95 •249- 

Another series of determinations, in confirmation of the 
first, was made by the old method of reducing molybdenum 
trioxide in hydrogen. The weights and results are sub- 
j oined : — 

MoOg. Mo. 

1-8033 1-2021 

1*7345 1-1564 

3-9413 2-6275 

1-5241 i-oi6o 

4-0533 2*7027 



Atomic weight of Mo. 
95-736 
95-777 
95756 
95-741 
95-813 



Mean.. 



95765 



go 



Action of Wagner* s Reagent upon Caffeine. 



Chemical NbWs, 

Feb. ig, 1807. 



Reduced to vacuum, Mo = 95735, a value very close to 
the other. When = 16, the atomic weight of molyb- 
denum is very near the even number 96. 

(To be continued). 



ON 



THE ACTION OF WAGNER'S REAGENT 
UPON CAFFEINE, AND 
A NEW METHOD FOR THE ESTIMATION 
OF CAFFEINE.' 

By M.GOMBERG. 
(Continued from p. 81). 



I. This sample was obtained by slowly adding a solution 
of iodine in potassium iodide to a solution of caffeine 
acidulated with sulphuric acid. The iodine was added 
until the supernatant liquid was decidedly red. The 
whole was allowed to stand three hours, filtered, washed, 
and dried as described above. The total iodine was esti- 
mated in the usual way, i.e., by suspending a weighed 
sample in water, adding sulphurous acid solution, then 
silver nitrate and nitric acid; filtered, washed, and dried. 
The " exterior " iodine, j.«., the iodine not as hydriodic 
acid, was estimated by dire(5t titration with standard so- 
dium thiosulphate. 

o'2oo2 grm. gave for total iodine 0'2785 grm. Agl. 
0-2358 „ ,, exterior „ 0-1433 „ I. 

II. This sample was obtained by adding to an acidulated 
solution of caffeine enough iodine to precipitate about 
one-half of the caffeine present. 

0-2563 grm. gave for total iodine 0-3591 grm. Agl. 
0-1659 ,, ,, exterior ,, 0-0997 n ^• 

III. A neutral solution of caffeine was mixed with an 
excess of Wagner's reagent, and to the mixture dilute 
sulphuric acid was gradually added so long as a precipi- 
tate was produced. 

0*4039 grm. gave for total iodine 0-5668 grm. Agl. 
0-1424 „ „ exterior „ 0-0866 ,, I. 

IV. Filtrates from I. and III, on long standing, gave a 
deposit of dark blue needle-like crystals, which were col- 
leded, washed, and dried as before. 

0-7884 grm. gave for total iodine 1-1064 gri"- Agl. 
0-4450 ,, ,, exterior ,, 0-2685 n !• 

V. This was obtained by re-crystallising the amorphous 
precipitate from methyl alcohol. 

0*2890 grm. gave for exterior iodine 0-1756 grm. I. 

VI. Obtained by re-crystallising the amorphous per- 
iodide from hot ethyl acetate. 

* From the Journal of the American Chemical Society, xviii., No. 4- 



0-4807 grm. gave for total iodine 0-6709 grm. Agl. 
0-2777 ,, „ exterior ,, 0-1622 ,, I. 

Calculated for Per Found. 

C,Hi,N«0,HI.l4.cent. I. II. III. IV. V. VI. 

Total iodine.. 7644 75-12 7566 75-84 75-83 — 75-40 

Exterioriodine 61-15 6079 6o-ii 6o-8i 60-34 60-76 60-22 

When some of the periodide is treated with a solution 
of sulphur dioxide, and then extrafled with chloroform, 
it furnishes unchanged caffeine. 

The composition of this periodide of caffeine appears 
to be difTer«nt from that described by Tilden (yourn. 
Chem. Soc, xviii., 99, 1865), which he obtained by exposing 
to sunlight an alcoholic solution of caffeine containing 
some hydriodic acid. The slow oxidation of the hydriodic 
acid furnished the iodine, and the compound thus ob- 
tained has the composition, according to Tilden, 
2(C8HioN402HI-l2)-3H20. It is a lower periodide than 
the one which is obtained when iodine dissolved in potas- 
sium iodide is diredlly added to caffeine, as the latter has 
the composition C8H10N4O2.HI.I4. Tilden also men- 
tions that by the addition of alcoholic iodine to a solution 
of caffeine in weak sulphuric or hydriodic acid, he ob- 
tained a deposition of black granules, which upon analysis 
furnished about 75 per cent of total iodine. He says that 
it probably consists of a compound containing nine atoms 
of iodine. But there is hardly any doubt that he had the 
tetraiodide of caffeine hydriodide. 

Properties. — When dry the periodide is a violet-blue 
amorphous powder melting at 213° C. When moist it 
rapidly loses iodine on exposure to air. It is permanent 
when dry, and suffers but slight loss when heated to 100° 
C. Two grms. heated for four hours at that temperature 
lost only 0-027 g'"'"- = i"33 per cent. It loses but very 
little of its iodine when suspended in water, giving up 
enough iodine to saturate the liquid. The presence of 
potassium iodide in the water favours the liberation of 
iodine, but even then it is but slight. The periodide dis- 
solves readily in alcohol, especially when heated, with 
considerable decomposition into the free base and iodine. 
It is more soluble in methyl alcohol and suffers less de- 
composition in that solvent. It can be obtained from 
methyl alcohol, on spontaneous evaporation of the sol- 
vent, in the form of beautiful crystals, with a metallic dark 
bluish lustre. When examined under the microscope the 
crystals appear to consist of six-sided prisms. Ether, 
whether cold or warm, decomposes it but slightly. The 
periodide is insoluble in chloroform, carbon disulphide, 
and benzene. It is soluble without decomposition in hot 
ethyl acetate, from which it separates on cooling as a dark 
granular crystalline deposit, which melts at 215° C. 

Limits of Precipitation. — Like most alkaloids, caffeine 
is precipitated by Wagner's reagent even from very dilute 
solutions of the base. Although not charadteristic, it is 
yet as delicate a test for caffeine as we have. The limits 
of precipitation, under the influence of different acids, will 
appear from the accompanying table. The tests apply to 
I c.c. of the solution mentioned, acidulated with two or 
three drops of the acid, and to this two drops of Wagner's 
reagent (twentieth normal) was added. 
(To be continued). 







Sulphuric acid. 


Hydrochloric acid. 


Nitric acid. 


Dilution. 


5 per cent. 


5 per cent. 


5 per cent. 




: 250 


Very heavy. 


Very heavy. 


Very heavy 




: 1000 


Very heavy. 


Very heavy. 


Very heavy 




■ 1500 


Heavy. 


Heavy. 


Heavy. 




. 3000 


Fair. 


Fair. 


Fair. 




5000 


Very slight. 


Slight. 


Slight. 




8000 


Very slight. 


Slight. 


Slight. 




zoooo 


None. 


Very slight. 


Very slight. 



Acetic acid. Oxalic acid. Tartaric acid. Citric acid. 
5 and 50 per cent. 5 per cent. 10 per cent. 10 per cent. 



None. 



Heavy. 
Heavy. 
Slight. 
Faint. 



Slight. 

Very slight. 

None. 



Faint. 
None. 



Chemical News, 
Feb. 19, 1897. < 



Determination of Atomic Masses by the Eiectrolytic Method 91 



THE ACTION OF BORON ON IRON AND 

STEEL, AND ERRORS IN IRON ANALYSIS 

ACCOUNTED FOR BY THE PRESENCE 

OF THAT ELEMENT. 

By H. N. WARREN, Principal, Liverpool Research Laboratory. 

Some five or six years ago a somewhat lengthy description 
was published in the Chemical News with rasped to the 
adion of boron upon metallic iron, which researches at 
that time led to the discovery of the now well-known 
compound boroneisen. 

Quite recently some rather remarkable notes have 
appeared in scientific literature of the preparation of that 
compound by the aid of eledlrical furnaces ; it is there- 
fore the author's intention, after a long and varied expe- 
rience with the element, to deny most emphatically that 
anything like such a temperature as the eledric arc is 
required in order to form a boro-ferric compound. Even 
ordinary ferric borate, obtained by precipitating ferric 
chloride by means of a soluble borate, may, after drying, 
be readily reduced, at a red heat, to an amorphous — and 
at the same time pyrophoric — boride ; or may be obtained 
of a silvery whiteness, fusible at a white heat and con- 
taining from 6 per cent boron, by melting the above- 
mentioned compound under a layer of borax, the 
compound being of sufficient hardness to cut glass and 
even scratch flint, the horon being set free in the ele- 
mentary condition by means of eledro dissolution. This, 
however, is by no means the only way of impregnating 
iron with boron ; on the other hand, it is extremely diffi- 
cult to prevent the formation of a boride, when a mixture 
of iron oxide and carbon is exposed to a temperature 
sufficient to melt the cast-iron thus produced, provided a 
fusible borate is used as a flux. Again, borax being such 
a desirable fluxing agent for metallurgic redudions, this 
compound is generally made use of in smelting small 
quantities of iron ores, for the purpose of further ex- 
amination of the iron thus obtained. This readtion is, 
however, perfectly useless, provided a fluxable borate has 
been employed, as one hundred samples thus reduced 
by the author all contained more or less boron, averaging 
up to 2 per cent, while at the same time the iron in most 
cases appears solely as white cast, the carbon existing in 
the combined form ; also, as a verification test, samples 
of cast-iron were exposed to different temperatures in 
common with fusible borates, the analyses of all these 
samples showing a deficiency on the total averaging from 
i to 2 per cent. 

Liverpool Research Laboratory, 
18, Albion Street, fiverton, Liverpool. 



VOLUMETRIC DETERMINATION 

OF MOLYBDENUM AND VANADIUM.* 

By CARL FRIEDHEIM. 

In concert with H. Euler I have elaborated a volumetric 
method for determining molybdenum. It consists in 
decomposing the molybdate or molybdenum teroxide in 
Bunsen's apparatus with potassium iodide and hydro- 
chloric acid, absorbing the liberated iodine in potassium 
iodide, and titrating with sodium thiosulphate in the 
usual manner. 

F. A. Gooch and Charlotte Fairbanks {Zeit. Anorg. 
Chem.) have submitted this process to a re-examination, 
with the result that satisfadlory values can be obtained 
only under conditions which they have ascertained and 
communicated. 

Stridly speaking, it might be sufficient to point out 
that (as it appears from the figures given in my former 

* Berichte A. Chem. Gcstll, 



communication), in my method the errors fluduate between 
— Cog and 4-0*36 (and not as Gooch and Fairbank state, 
between -fo"05 and 1-13 per cent), whilst the authors 
just named obtain errors of from — 0*14 to -fo*45, in order 
to prove that, according to the proposed modification, the 
results obtained are not better, but worse. But as my 
method admits of more general application, and on this 
account any additional difficulty must be avoided such as 
would be involved in the new proposals, I must examine 
more closely some of the declarations of Gooch and Fair- 
banks. 

The hydriodic acid liberated on treating molybdenum 
teroxide with potassium iodide and hydriodic acid is 
naturally — in as far as it is not oxidised by the molyb- 
denum teroxide — decomposed by the oxygen of the a tmo- 
sphere, which naturally must signify an increased elimina- 
tion of iodine. This I pointed out expressly in my former 
communication, in which it is stated: — " We have found 
that this process of determination can be carried out — 
with the due observation of certain precautions — much 
more rapidly and quite as accurately in Bunsen's appa- 
ratus, and therefore by distilling the substance with 
potassium iodide and hydrochloric acid." 

But if we heat the mixture of the above substances 
rapidly, too much iodine is liberated in the receiver ; but 
if we work in such a manner that the redudion of the 
substance is efFeded before hydriodic acid escapes, we 
obtain the theoretical quantity of iodine. 

Hence the following modus operandi results for the 
execution of the method : — o'2 to 03 grm. of the molyb- 
date are mixed in the decomposition flask of Bunsen 
apparatus with o'5 to 0*75 grm. of potassium iodide, and 
so much hydrochloric acid of sp. gr. i'i2 that the liquid 
may fill two-thirds of the flask. After connedion with 
the escape tube and its introdudion into the receiver, the 
contents of the flask are very slowly heated so as to reach 
ebullition, when the escape tube is filled as far as possible 
with iodine vapour and is just on the point of reflux. 
When the iodine is completely expelled, i.e., when no 
more violet fumes are visible, and the solution takes a 
light-green colour, the distillation is at once broken ofT, 
and the iodine absorbed by potassium iodide in the 
receiver is titrated with sodium thiosulphate. 

When Gooch and Fairbanks repeat these diredions 
with the words " that the flask is two-thirds filled," and 
continue " the solution is not raised to ebullition until 
the flask is entirely filled with the heavy vapours of iodine, 
and is continued until iodine is no longer visible, and the 
liquid has taken a light-green colour," they have evidently 
' quite overlooked that I laid particular emphasis on the 
exclusion of air; that is, on the non-contad of air and 
hydriodic acid. 

(To be continued). 



THE DETERMINATION OF ATOMIC MASSES 

OF SILVER, MERCURY, AND CADMIUM, 

BY THE ELECTROLYTIC METHOD.* 

By WILLETT LEPLEY HARDIN. 

(Continued from p. 79). 

Part III. 
Determination oj the Atomic Mass of Cadmium. 
Nine experimenters have determined the atomic mass 
of cadmium by many different methods, but the large 
variations in the results given by different chemists leave 
the true value of this constant still uncertain. 

Stromeyer (Beizelius' " Lehrbuch," 5th Edition, iii., 
i2ig) gave no details of his method of operation, but 

* Contribution firom the Joha Harrison Laboratory of Chemistry 
No. 13. From the author's thesis presented to the Faculty of the 
University of Pennsylvania for the degree of Ph.D. — From the 
Journal of the American Chemical Society, xviii., p. 990. 



9^ Determtnaiion of Atomic Masses by the Electrolytic Method. 



Chemical Mbwb, 
Feb. ig 1807. 



found that 100 parts of cadmium combined with 14,352 
parts of oxygen. On the basis of 0=i6, this ratio gives 
111-483 for the atomic mass of cadmium. This result is 
much lower than those obtained by other experimenters, 
and is perhaps only of historical interest. 

In a series of nine experiments, Von Hauer {jfourn. 
Prakt. Chetn., Ixxii., 350) determined the ratio of cadmium 
sulphate to cadmium sulphide. The sulphate used was 
purified by repeated re-crystallisations, and was finally 
dried at a temperature of 200°. After weighing the sul- 
phate was always dried a second time and re-weighed. 
The two weighings never differed as much as one m.grm. 
The sulphide obtained was in each case tested for sulphate 
The redudlion of the sulphate to sulphide was accom- 
plished by heating the sulphate in a current of dry 
hydrogen sulphide under pressure. The mean of nine 
observations computed on the basis of = 16 and 8 = 32*06 
gives 111*93 ^o"" 'h^ atomic mass of cadmium. Con- 
sidering the large quantity of material used each time, 
and the precautions taken to insure accuracy, there seems 
to be little objedtion to the method. 

Dumas (Ann. Chim. Phys., [3J, Iv., 158) determined 
the ratio of cadmium chloride to metallic silver by titrating 
a solution containing a weighed quantity of cadmium 
chloride with a silver nitrate solution of known strength. 
The cadmium chloride was prepared by dissolving metallic 
cadmium in boiling hydrochloric acid. The solution was 
evaporated to dryness, and the chloride fused for six hours 
in a current of hydrochloric acid gas. The mean of six 
determinations gives 112*24 for the atomic mass of 
cadmium (O- 16). 

Maximum result, Cd = 1 12759 
Minimum ,, Cd = 111*756 



Difference = 1003 

This large variation in the results obtained indicates 
the presence of impurities in the material used. In the 
first three experiments the cadmium was not purified ; the 
mean of these three is Cd = 112*476. The metal used in 
the last three experiments was considered by Dumas to 
be absolutely pure ; the mean of the last three results is 
Cd = 112*007. From the degree of purity of the cadmium 
chloride used in the different experiments, Dumas was 
inclined te rejeift the higher results, and concluded that 
the true atomic mass of cadmium was about 112. 

Lensen {yourn. Prakt. Chem., Ixxix., 281) prepared 
pure cadmium oxalate by precipitating a solution of 
cadmium chloride, purified by repeated crystallisation, 
with pure oxalic acid. The precipitate was washed and 
carefully dried at a temperature of 150°. The mean of 
three results obtained by converting a weighed portion 
of the oxalate to oxide gives 112*06 for the atomic mass 
of cadmium (0 = i6), The small quantity of material 
used in the different experiments is somewhat objedtion- 
able. 

Huntington {Proc. Amer. Acad., xvii., 28) under the 
diredtion of Cooke, determined the ratio of cadmium 
bromide to silver bromide, and also the ratio of cadmium 
bromide to metallic silver. The bromide used was pre- 
pared by dissolving cadmium carbonate, which had been 
carefully purified, in pure hydrobromic acid. The produdl 
obtained was dried at a temperature of 200°, and finally 
sublimed in a porcelain tube in a current of dry carbon 
dioxide. In the first series of experiments the silver 
bromide corresponding to the cadmium bromide used was 
weighed. The mean of eight determinations computed 
from the total quantity of material used and silver 
bromide obtained, on the basis of Ag = 107*93 and 
Br=79*95, is Cd = ii2 24. In the second series of experi- 
ments the quantity of metallic silver required to precipi- 
tate a known quantity of cadmium bromide was deter- 
mined. The mean of eight determinations computed as 
in the first series gives 112*245 for the atomic mass of 
cadmium. The separate determinations in both series 
agree very closely. 



Partridge {Amer. yourn. Set., [3] , xi., 377) made three 
series of determinations. The first depended upon the 
conversion of cadmium oxalate into oxide, the second, on 
the redudlion of the sulphate to sulphide, and the third, 
on the conversion of the oxalate into sulphide. The cad- 
mium used in these experiments was purified by distilling 
twice in vacuo. Ten observations on the conversion of 
the oxalate into oxide, computed on the basis of = 16 
and C = i2, give iii'8oi as a mean for the atomic mass of 
cadmium. Re-calculated by Clarke {Amer. Chem. yourn., 
xiii., 34), on the basis of = i6 and C= 12*005, ^^^ 
atomic mass of cadmium becomes iii'SiS. The mean 
of ten results obtained by reducing the sulphate to sul- 
phide, computed on the basis of = i6 and 8=32, gives 
111-797 for the atomic mass of cadmium. Re-calculated 
by Clarke on the basis of = i6 and 8=32*074, the atomic 
mass of cadmium is iii'7ii. In the third series the 
oxalate of cadmium was converted into sulphide by 
heating in a current of dry hydrogen sulphide. The 
mean of ten determinations, computed on the basis of 
= 16 and 8 = 32, gives 111*805 for the atomic mass of 
cadmium. Re-calculated by Clarke on the basis of = l6 
and 8=32*074, the mean becomes 111*589. Partridge 
gives 111*8 for the atomic mass of cadmium, as a mean 
of the three series. If the higher values for carbon and 
sulphur be introduced this value becomes somewhat lower. 

Jones {Amer. Chem. yourn., xiv., 261) determined the 
atomic mass of cadmium by two different methods. The 
first was based on the conversion of the metal into oxide, 
and the second on the conversion of the oxalate into 
oxide. The cadmium used was distilled six times in 
vacuo. The last distillate was tested spedtroscopically, 
and found to be free from impurities. In the first series 
of experiments a weighed portion of the pure metal was 
dissolved in pure nitric acid in a porcelain crucible. The 
solution was evaporated to dryness, and the resulting 
cadmium nitrate ignited to oxide. The final decomposi- 
tion was accomplished by means of a blast lamp. 
Reducing gases were carefully excluded from the crucible 
during the process of ignition. The weighings were all 
made against a tared crucible. The mean often observa- 
tions, computed on a basis of = i6, gives 112*07 for the 
atomic mass of cadmium. The different determinations 
agree very closely. In the second series of experiments 
cadmium oxalate, prepared by precipitating pure cadmium 
nitrate with pure oxalic acid, was converted into oxide. 
The material was carefully ignited until the oxalate was 
decomposed ; it was then treated with nitric acid, and 
again ignited in a manner similar to that described in the 
first series. The mean of five determinations computed 
on the basis of = i6 and C = i2*oo3, is Cd = iii*032. 
From all the observations Jones concludes that 112*07 
represents very closely the atomic mass of cadmium 
(0 = i6). 

Lorimer and Smith {Ztschr. Anorg. Chem., i., 364) 
determined the ratio of the atomic mass of cadmium to 
that of oxygen by dissolving pure cadmium oxide in 
potassium cyanide and electrolysing the solution. To 
obtain pure material, the commercial cadmium was dis- 
solved in nitric acid, and the solution evaporated to 
crystallisation. The crystals of cadmium nitrate were 
removed from the liquid, dissolved in pure water, and 
re-crystallised. The produdt obtained by the second 
re-crystallisation was dissolved in a little water and 
treated with a slight excess of potassium cyanide in a 
platinum dish. From this solution the metallic cadmium 
was thrown out by means of the ele&ric current. The 
nitrate obtained by dissolving the eledrolytic cadmium in 
pure nitric acid was tested spedroscopically and found to 
be free from impurities. The pure cadmium nitrate was 
digested with ammonium hydroxide and ammonium 
carbonate, and the resulting cadmium carbonate ignited 
to oxide in a platinum crucible. The method of opera- 
tion was very simple, a weighed portion of the oxide was 
dissolved in puie potassium cyanide, the solution eledlro- 
ysed, and the resulting metallic cadmium weighed. The 

I 



Chemical >HWt>, 
Feb. 19, 1897. 



Use of very small Mirrors wuh Faraffin Lamp and Scale, 



93 



mean of nine observations computed on the basis of 
0= 16 gives II2"055 for the atomic mass of cadmium. 

Bucher (Thesis, Johns Hopkins University, 1894) made 
six series of experiments. The cadmium used was puri- 
fied by nine distillations in vacuo. The weighings were 
all reduced to a vacuum standard, and computed on the 
basis of = 16, S = 32"05g, C = i2*oo3, Cl = 35"45, 
Br=79'95, and Ag=io7'93. 

In the first series cadmium oxalate, dried for fifiy 
hours at 150°, was ignited to oxide. The mean of eight 
observations gives iii'Sg for the atomic mass of cadmium. 

In the second series, cadmium oxalate was converted 
into sulphide by heating in a current of dry hydrogen 
sulphide. Ths mean of four determinations is Cd = 
11215. 

In the third series a weighed quantity of cadmium 
chloride, dried at a temperature of 300° in hydrochloric 
acid gas, was precipitated with silver nitrate, and the 
resulting silver chloiide weighed. The mean of tweniy- 
one determinations isCd = H2'39. The separate observa- 
tions in this series agree very closely. 

The fourth series was similar to the third, except that 
cadmium bromide was used instead of the chloride. 
The mean of five determinations isCd = ii2"38, a result 
almost identical with that obtained from the chloride. 

In the fifth series a weighed portion of metallic cadmium 
was converted into sulphate, which was dried at 400° and 
weighed. The excess of sulphuric acid which remained 
with the sulphate was estimated and its weight dedudled. 
The only result given is Cd = ii2-35. 

In the last series metallic cadmium was converted into 
oxide by dissolving in nitric acid and igniting the resulting 
cadmium nitrate. The mean of two determinations made 
by igniting the material in a porcelain crucible gives 
ii2'o8 for the atomic mass of cadmium. Three similar 
determinations made with a platinum crucible gave sis a 
mean Cd = iii'87. From a series of experiments on 
cadmium oxide, Bucher concluded that a corredion 
should be applied to the last and also the first series. 
By making this corredlion, the results in these two scries 
would be very close to those obtained from the chloride 
and bromide. 

From all the preceding determinations Clarke gives 
II 1*93 as the most probable value for the atomic mass of 
cadmium. The large variation in the results of different 
experimenters has not been fully explained. Some 
chemists think that the larger values are due to a higher 
degree of purity in the metallic cadmium used, and hence 
regard these values as being more nearly correrSt. But it 
must be remembered that the reverse is true in the experi- 
ments of Dumas. From material which had not been 
purified, Dumas obtained results ranging from ii2'32 to 
ii2'76 for the atomic mass of cadmium, while from 
material which he considered absolutely pure, the results 
were from 11176 to ii2'i3. 

Preparation of Pure Cadmium. 

The metallic cadmium used in these experiments was 
purified by distillation in a current of hydrogen which had 
been passed through solutions of caustic potash, lead 
nitrate, potassium permanganate, and sulphuric acid. A 
hard glass combustion tube was heated to redness, and 
the walls of the tube indented at two points with a three- 
cornered file. This divided the tube into three parts. 
Commercial cadmium was placed in one end of the tube, 
and connedion made with the hydrogen generator. 
After complete removal of the air, the tube was carefully 
heated in a combustion furnace until one-half of the 
metal had distilled over into the middle portion of the 
tube. The metal was cooled in a current of hydrogen. 
The tube was then broken and the metal removed. The 
portions in the first and last sedtions of the tube were 
rejefted. The middle portion was placed in a second 
coiiibusiiun tube, similar to the first, and the distillation 
repeated. After three distillations the metal was 



examined spedtroscopically and found to be free from 
impurities. 

(To be continued). 



PROCEEDINGS OF SOCIETIES. 

PHYSICAL SOCIETY. 
Special General Meeting, February 12th, 1897. 

The Chair was taken by Captain Abney, who, as retiring 
President, referred to some of the changes which had 
occurred in the Society during the past year. 

The Annual Subscription had been raised, but a satis- 
fadlory number of new Fellows had been enrolled. The 
Society had lost two by death. A good deal of work had 
been done in the diredion suggested by the discoveries of 
Rontgen. 

The Treasurer, Dr. Atkinson, then presented his 
Report and Balance-sheet for the year 1896. There was 
evidence of improvement in the financial position, but 
there was still a deficiency to be met. Profits from sales 
of publications had been small ; it was desirable to reduce 
the price of the volumes of colleded papers of Joule and 
Whe itstone, and to call the attention of physicists to 
these valuable records of classical wurk. 

Mr. Walker suggested that physical laboratories, 
especially those in London, should be visited by Fellows 
of the Society, with a view to comparing notes as to the 
construdlion of apparatus ; professors of colleges and 
other institutions should be invited to appoint visiting days 
for this purpose. 

Votes of thanks were passed to the retiring President, 
Council, and Officers, and also to the Council of the 
Chemical Society for the use of their rooms at Burlington 
House. 

In replying, Capt. Abney said that the coming year 
would probably bring about further improvements in the 
system of abstradting and indexing, by co-operation with 
other societies at home and abroad. He then read the 
list of Council and Officers for the year 1897-8: — 

President—Sh&Uoid Bidwell, M.A., LL.B., F.R.S. 

Vice-Presidents, who have filled the Office of President 
—Dr. Gladstone, Prof. G. C. Foster, Prof. Adams, The 
Lord Kelvin, Prof. Clifton, Prof. Reinold, Prof. Ayrton, 
Prof. Fitzgerald, Prof. Riicker, Capt. Abney. 

Vice-Presidents— Maj.-Gen. E. R. Festing, L. Fletcher, 
Prof. Perry, G, Johnstone Stoney. 

Secretaries— r. H. Blakesley, H. M. Elder. 

Foreign Secretary (new office)— Prof. S. P. Thompson. 

Treasurer — Dr. Atkinson. 

Librarian — C. Vernon Boys. 

Other Members of Council— Waltti Bailey, L. Clark, 
A. H. Fison, Prof. Fleming, R. J. Glazebrook, Prof. A. 
Gray, G. Griffith, Prof. Minchin, Prof. Ramsay, J. 
Walker. 

The newly-eleded President, Mr. Shelford Bidwell, 
then took the Chair, and an Ordinary Meeting was held. 

Mr. Blakesley read a paper by Mr. H. H. Hoffert, 
" On the Use of very small Mirrors with Paraffin Lamp 
and Scale." 

For the mirrors of refledling instruments the author 
prefers small redangular strips of microscope cover-glass, 
chosen thin and plane. These are first silvered, and then 
cut to shape by a splinter of diamond embedded in wax. 
They are about 8 m.m. long by i'5 m.m. broad, and are 
suspended so that their longest sides are vertical. Red- 
angular mirrors suspended in this way are lighter, and 
have less inertia than round mirrors of equal aperture. 
A paraffin-lamp flame placed edgewise to the mirror gives 
b^ufiicient illumination. The image of the flame is focussed 
on the mrrror by a lens midway between them ; it is a 



94 



Water and its Purification . 



t CftBMiCAL News, 
I Feb. 19, 1897. 



right vertical line, and thiis conforms to the shape of the 
mirror. A scale is fixed upon a screen between the lens 
and lamp ; and the screen has a circular aperture just 
below the centre of the scale, provided with a vertical 
cross-wire. The relative position of screen and lens is 
adjusted so that an image of the wire is formed upon the 
scale after reflexion at the mirror. 

Mr. Boys said he had frequently used small mirrors 
construdted as described by the author, and he could not 
see what was new in the method, except that a paraffin 
lamp had been found sufficiently bright for the purpose. 
It is desirable to diminish inertia by choosing extremely 
thin glass. Microscope cover-glasses are generally sup- 
plied in squares or discs very fairly equal in size; if they 
are dealt out on a table, like a pack of cards, their rela- 
tive thicknesses can be judged by the note produced as 
they fall. Flatness can be estimated nearly enough by 
balancing them one by one upon the knuckle, nearly level 
with the eye, and observing the refledion of an illuminated 
straight edge, such as a window-bar. All rejected glasses 
should be broken. The good ones can be further examined 
by a telescope and artificial star. A common writing 
diamond is best for cutting the thin plates. Special care 
must be taken not to distort the mirror in fixing to the 
suspended system. If liquid shellac is used in the attach- 
ment distortion will certainly occur, — at any rate, if it is 
applied throughout the whole length of the mirror. The 
best way is to make the attachment at a mere point, 
near the top of the mirror, using a speck of shellac 
as viscous as possible, and heating, if necessary, by 
radiation, not by condudtion. Mr. Boys thought that a 
refiedling prism near the mirror might be used in certain 
cases where a paraffin lamp with its inevitable vertical 
flame was required for horizontal proje(5lions. For general 
purposes Mr. Boys prefers some sucFi arrangement as the 
following: — If the source of light is a point, a lens is 
employed, forming an image of the source upon the 
mirror. (If the source of light is a surface, this 
lens is evidently superfluous). The cross-wire is stretched 
near to the lens on the side towards the mirror. It is now 
necessary to focus the cross-wire upon the scale, and this 
is best done by a plano-convex fixed lens as near as pos- 
sible to the mirror, with its plane face towards the mirror. 
The light passes twice through the lens. As it may be 
necessary to change the plano-convex lens from time to 
time, according to the distance of the scale, Mr. Boys 
attaches it with a little vaseline to a strip of plate glass 
in front of the instrument. One advantage of such an 
optical system is that it allows the instrument to be set 
up in the same position with respedt to the scale at all 
times. 

Dr. Thompson pointed out that Mr. Hoifert had ob- 
tained his results using only one lens, by properly choosing 
the position of the cross-wire. 

A vote of thanks was given to the author, and the 
meeting adjourned until February 26th. 



NOTICES OF BOOKS. 



Water and its Purification ; a Handbook for the Use of 
Local Authorities, Sanitary Officers, and others inte- 
rested in Water Supply. By Samuel Rjdeal, D.Sc, 
Fellow of University College, London, F.I.C. ; 
Examiner in Chemistry to Royal College of Physicians ; 
Public Analyst for the Lewisham Distrift Board of 
Works ; Water Examiner to the Guildford Rural Dis- 
tridl Council ; Author of " Disinfedion and Disinfedt- 
ants." With numerous Illustrations and Tables. 
London : Crosby Lockwood and Son, Stationers' Hall 
Court. Pp. 292. 1897. 

Writings discussing municipal water supply resolve 
themselves into two grand categories. The one deals 



with the outgoing waters, their purification or disinfection, 
and their utilisation. The other class, of which the 
volume before us is an excellent specimen, discusses the 
incoming waters, their suitability for domestic and indus- 
trial purposes, and their improvement whenever pradti- 
cable. 

In the remarks on natural waters Dr. Rideal shows 
that an appeal to the physical charadters of a water is 
not trustworthy, and may even be dangerously deceptive. 
He rightly urges that even traces of the poisonous metals 
render a water inadmissible for household consumption. 
Lead, the most insidious and dangerous of metallic 
impurities, is, unfortunately, often introduced by lead 
service-pipes. Some waters, however, have the dangerous 
property of rapidly attacking lead. This is especially the 
case with peaty waters. Cisterns for water-supply are 
rightly and emphatically condemned. 

It is an unfortunate circumstance that the upland areas, 
uncultivated and unpeopled, are not sufficient to afford 
drainage grounds for the supply of adjacent cities. The 
instance of Manchester is most instrudtive. A few years 
ago its supply from a series of reservoirs construdted in 
Longdendale (not Longerdale), the drainage off the mill- 
stone grit, and the uncultivated moor-lands, was viewed 
as sufficient not merely for the present but the future. 
But recently it has been found insufficient, and an addi- 
tional supply has been obtained from Thirlmere in Cum- 
berland. Contrary to our fears the engineering operations 
near this lake have not interfered with the beauty of the 
scenery. 

Dr. Rideal rightly kolds that it is the duty of the State 
to apportion the upland water-sources to the needs of the 
population. 

Mention is made of the Holmfirth catastrophe, and of 
the still more appalling disaster at Sheffield. 

The London County Council proposes to derive the 
future supply of the metropolis from Wales, taking the 
head waters of the Usk, Wye, and Towey, and conveying 
them by two aquedudts of respedlively 150 and 175 miles 
in length. The great objedlion to this scheme would be 
the necessity of guarding the aquedudls and bridges from 
possible mischief on the part of bodies whom— as wo are 
not a political organ — we cannot here point out. The 
sujjgestion that the purer mountain water might be 
" exclusively used for drinking purposes," and employing 
ordinary waters for washing, trade, and sanitary purposes, 
would certainly lessen the demand on the upland areas, 
but would at the same time burden the consumer with 
the expense of a duplicate system of mains and service 
pipes. 

On page loi we find the standards of the Thames 
Conservancy. This body demands that discharges into 
the river must be : — 

1. Free from offensive odour. 

2. Free from suspended matter. 

3. Neither acid or alkaline to test papers. 

This requirement Dr. Rideal acutely pronounces 
impossible, since natural waters are almost invariably 
acid to one test on account of free carbonic acid, and 
alkaline to another owing to carbonates. The author 
suggests that limits of permissibility should be given. 

4. Not more than 60 grs. per gallon of total solids. 

5. Not more than 2 grs. per gallon of organic carbon, 
and 075 grs. per gallon of organic and ammoniacal 
nitrogen. 

6. Not less than one cubic inch of free oxygen per 
gallon. 

Concerning the adtion of soft waters upon leads we 
find two conflidling statements. On page 117 we read 
" that its (the water of Loch Katrine) only fault is that it 
adls rapidly upon lead, of which we shall speak further." 
But on page 137, after speaking of the soft water of the 
Varty (Dublin), the author writes : " The equally soft 
water of Lock Katrine has little or no adtion upon this 
metal." 



Cbxuical Nxwb, I 
Feb. ig, 1897. ) 



Chemical Notices from Foreign Sources, 



95 



On page 97 Dr. Rideal points out the danger of allowing ^ 
pigs to wade in streams, and consequently to introduce 
into them parasites. 

The self-purification of rivers is exemplified in Dr. P. 
Frankland's paper on the river Dee (p. 105). 

On the question of constant v. intermittent water 
service the author takes the right view, condemning the 
latter procedure, which has justly gone out of use in most 
places except London. 

In speaking of filters, which the author does at great 
length and with thorough fairness and accuracy, he shows 
that all domestic filters, except the Pasteur-Chamberland, 
are of very doubtful efficacy, if not positively harmful. 
The Berkenfeld filter requires to be boiled either once or 
twice every twenty-four hours. 

Referring to the mains and service pipes for the distri- 
bution of water in cities, our author recommends that the 
pipes should be laid not less than four feet below the sur- 
face, and should pass within about three feet of the kitchen 
grate before branching off to different parts of the 
establishment. 

It is unfortunate that no one has the power to enforce 
these standards as against "Jerry." 

In our opinion Dr. Rideal has made in this book a 
valuable contribution to our sanitary literature. 



CHEMICAL 



NOTICES FROM 
SOURCES. 



FOREIGN 



Note.— All degrees of temperature ate Centigrade unless otherwise 
expressed. 

Comptes Rendus Hebdomadairts des Seances, de V Academie 
des Sciences. Vol. cxxiv., No. 3, January i8, 1897. 

Researches on Helium. — M. Berthelot.— The author 
has succeeded in combining helium, both with the ele- 
ments of the hydrogen carbides, and with those of carbon 
disulphide, with the intervention of mercury and the in- 
fluence of the eledtric effluve, all precisely under the 
same conditions in which he has realised the combina- 
tion of argon. In both cases these syntheses have been 
checked by analysis ; that is to say, by the regeneration 
of the element in a free state. 

Remarks on the Specific Heats of Elementary 
Gases, and on their Atomic Constitution. — M. 
Berthelot. — The author calls attention to the following 
values of specific heat at constant volumes, referred to 
an identical volume of the elements, such as that occupied 
by 2. grms. of hydrogen : — 
Gas with a monatomic mol. 3*0 

Diatomic gas 4'8 (not split up at present, 

and 66 split up above 

Tetratomic gases il'4 

It will be remarked that the ratio of these values, measured 
near the ordinary temperature (between 0° and 300°), is 
not remote from that of i : 2 : 4 ; that is to say, that the 
specific heats of the simple gases at a constant volume 
are approximately proportional to the number of atoms 
contained in the molecule. Besides the four groups of 
gaseous elements just distinguished, there are others, 
such as contain triatomic elements, e.g., ozone, com- 
parable to hyponitric gas; and certain hexatomic ele- 
ments, sulphur and selenium. But their specific heat is 
hitherto unknown. We know how for the simplified 
notions deduced from a first study of the elementary 
gases anciently known, e.g., hydrogen, oxygen, and nitro- 
gen, there are being substituted more profound notions on 
the physico-chemical constitution of the elements. 

Classification of the Chemical Elements. — Lecoq 
de Boisbaudran. — This paper will be inserted at some 
length. 



Certain Salts and Derivatives of Dinitro-ortho- 
cresol. — P. Cazeneuve. 

Law of the Transparency of Gases for X Rays. — 
L. Benoist. — In the earliest experiments on the X rays it 
was remarked that the opacity of different bodies 
for the rays increased in general with their density, and 
it was thought that a simple relation such as diredt pro* 
portionality might exist between these two charaders. 
With gaseous bodies the case is different. With sul- 
phurous acid, methyl chloride, and air the absorption pro- 
duced is proportional to the density of the gas employed. 
This is the relation which Lenard has already obtained for 
the kathodic rays before Rontgen's discovery. As the 
specific absorbent power of gases resulting from the fore- 
going measurements gives the value 0*14, aluminium 
gives the value 0*09 ; the deviation is not great, whence 
aluminium would almost satisfy a general law of propor- 
tionality between the absorbent power and the density. 
On the contrary, silver gave 0*84 — a number six times too 
great. 

Speed of the Redu(5tion of Chromic Acid by Phos- 
phorous Acid. — G. Viard. — This paper requires the for- 
mulae and the table here introduced. 

Ac^tion of Hydrogen Sulphide and Selenide upon 
Phosphonyl Chloride. — A. Besson. — If we dissolve dry 
hydrogen sulphide at 0° in POCI3 and leave it in a closed 
vessel, in a few hours the liquid becomes milky, and after 
twenty-four hours there colleds at the lower part of the 
vessel a light bulky amorphous precipitate, whilst the 
supernatant liquid becomes limpid. If the experiment is 
prolonged, there is a slow formation of crystalline needles. 
Both the amorphous precipitate and the crystalline 
needles have the same composition, P2O2S3 ; that is, an 
oxy-sulphide. Dry hydrogen selenide has no perceptible 
adtion upon POCI3 in the cold, but at 100° it readts slowly, 
forming phosphonyl selenide. 

A(5tion of Ethyloxalyl Chloride upon Pseudo- 
cumene and Mesitylene. — E. Bouveault. — These two 
papers are not suitable for abridgment. 

Decrease of the Nitrogenous Matter in the Wheats 
of the Department " Du Nord."— M. Balland.— The 
nitrogenous matter, which in 1848 varied between io'23 
and i3'02 per cent, is now between 8-96 and io'62 per 
cent. 



The Reprodu(aion of Colour by Photographic 
Methods. — Sir Henry Trueman Wood is announced to 
read a paper at the Society of Arts on this subjed on the 
24th inst. Captain Abney, C.B., F.R.S., will preside. 
Illustrations will be shown of several of the recently 
invented processes for the photographic reprodudion of 
colour. 

On Chromium and Manganese Phosphides. — A. 
Granger. — The analysis of these phosphides is delicate, 
on account of the difficulty ot separating phosphoric acid 
from chromium and manganese oxides. The author 
reduced the substances to a fine powder, treated them 
with melting potassa, raising the temperature gradually 
to dull redness, and keeping the mass in tranquil fusion 
for li hours. The mass, when cold, is dissolved in 
boiling water, acidified with nitric acid in the case of 
chrome, or with hydrochloric acid in the case of man- 
ganese. The chromic solution is then treated with ammo- 
nium molybdate to precipitate phosphoric acid. In the 
filtrate the chlorate is reduced to the state of a salt of 
chrome which is precipitated in the state of sesquioxide, 
carrying molybdenum down with it. The precipitate, 
dissolved and re-precipitated, yields an oxide sufficiently 
free from foreign salts. The manganic solution, eva- 
porated to dryness with hydrochloric acid in excess, is 
neutralised with ammonia, and ammonium sulphide is 
added. We evaporate to dryness, and add a further 
quantity of the latter reagent ; re-dissolved in water, and 
filtered, the precipitate contains all the manganese, and 
in the fil'rate the phosphoric acid is determined as usual. 



96 



Meetings for the Week, 



Chemical News, 
Feb 19, 1897. 



MEETINGS FOR THE WEEK. 

M ONDAT, 22nd.— Society of Arts, 8. (Cantor Leftures). "Industrial 
Uses of Cellulose," by C. F. Cross, F.C.S. 
Tuesday, 23rd.— Royal Institution, 3. " Animal Elefiricity," by 

Prof A. D. Waller, F.R.S. 
Wednesday, 24th.— Society of Arts, 8. " ReproducSion of Colour by 
Photographic Methods," by Sir Henry True- 
man Wood. 
Thursday, 25th.— Royal Institution, 3. " The Problems of Araic 
Geology," by J. W. Gregory, D.Sc, F.R.S. 

Society of Arts, 8. " The Mechanical Production 

of Cold," by Prof. James A. Ewing, M.A., F.R.S. 
Friday, 26th.— Royal Institution, 9. " Palestine Exploration," by 
Lieut. Col. C. R. Conder, R.E. 

Physical, 5. "Photography of Ripples," by J. H. 

Vincent. 
Saturday, 27th.— Royal Institution, 3. " The Growth of the 
Mediterranean Route to the East," by Walter 
Frewen Loid. 



TO CORRESPONDENTS. 

.4.G. i4.— You had better write to the Secretaries of the various 
societies to which you wish to belong. They will send full particulars 
of qualifications required. 



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One with a good knowledge of the Manufacture of Small 
Chemicals preferred.— Please apply, in strift confidence, giving full 
information as to age, experience, and salary required, to " Manu- 
fadlurer," Chemical News Office, 6 & 7, Creed Lane, Ludgate Hill, 
London, E.G. 

hemist wanted, Chemical Works in London. 

— His duties would be principally in the Lsboratory, but it 
would be essential that applicants should have had pra<5tical experi- 
ence as Works Manager.— Reply, stating age, past experience, and 
salary required, to C.C.C, care of Clarke, Son, and Piatt, 85, Grace- 
church St., London, 

Works' Chemist, A.I.C., late with large 
London manufafturers, well up in Plant and Building Con- 
struction, experience in management of men, and in conduction of 
Technical Research work, good Commercial Analyst, seeks Appoint- 
ment. Moderate Salary.— Address, " Plant," Chemical News Office, 

6 & 7, Creed Lane, Ludg ate Hill, London, E.G. 

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Being Contributions to the Life-History of MicroOrganisms. 

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London: E. & F. N. SPON, Ltd. , 125, Strand^ 
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^^p'eb.'a^is^T''} Removal of Oxide from Melted Copper and Copper Alloys, 



97 



THE CHEMICAL NEWS 



Vol. LXXV., No. 1944. 



ON THE 

REMOVAL OF OXIDE FROM MELTED COPPER 

AND COPPER ALLOYS. 

By SERGIUS KERN, M.E., St. Petersburg. 

The following is perhaps not new to many metallurgists, 
but the modus operandi of the application of phosphorus 
for cleaning copper alloys, just before casting them into 
ingots or mouldings, must be new to many. 

In order to reduce the oxides and to obtain dense and 
solid castings, for several years the Obouchoff Works 
here have successfully used our plan, which is as 
follows : — 

In order to safely throw the phosphorus into the pots 
of melted copper, just before drawing them out of the 
furnace, the phosphorus is submitted to the following 
treatment : — Phosphorus is cut into pieces, weighing 
about 3 ounces each, and placed in a concentrated 
solution of copper sulphate, where it is kept for further 
use. From time to time fresh copper sulphate is added, 
and pieces of phosphorus also, after taking out for 
foundry uses pieces of phosphorus already covered with 
precipitated copper. 

In this manner it is easy to handle phosphorus, which 
also when thrown into pots does not take fire at once, 
but safely reaches the melted metal to adt in the desired 
manner. 

About two pieces are usually sufficient for i cwt. of 
metal in the pot. 

The addition of phosphorus in the mentioned manner 
to copper plays the part of ferromanganese to steel. 

February 13, 1897. 



concludes that their observations were pradtically only 
corredt so far as they agreed with those of Schonbein. 
The author has also investigated the aiftion of precipitated 
mercuric oxide upon iodine water, and find that hypo- 
iodous acid is formed. The filtered (colourless) solution 
possesses only the feeblest possible bleaching properties, 
but the addition of a little alkali transforms it at 
once into as strong a bleaching solution as Schonbein's, 
and which it now exadlly resembles. By the methods 
mentioned above it is found that from 40 to 45 per cent, 
out of a possible 50 per cent, of the iodine used exists in 
the solution as hypoiodous acid. By using iodine water 
and a little suspended iodine, a stronger solution is ob- 
tained, which very soon decomposes, turning brown, 
owing to the liberation of iodine. The hypoiodous acid 
probably decomposes as follows : — 

3HOI = 2HI + HIO3. 
and the hydriodic acid and iodic acid immediately decom- 
pose each other, with liberation of iodine. The author 
suggests a possible explanation of the feeble bleaching 
power of the free acid in the instability of the hydriodic 
acid which will be left, compared with the alkaline 
iodides. 

A solution containing hypoiodous acid also appears to 
be formed by the adtion of various silver salts upon iodine 
water, the best results being obtained with silver nitrate 
and silver carbonate. These liquids bleach much more 
rapidly than the one described above, probably because of 
the silver which is present ; but they are much less rapid 
in their bleaching adtion than the alkaline hypoiodites. In 
other respedts they resemble Schonbein's solutions, being, 
however, much less stable, this again being probably due 
to the presence of silver in the solution. The liquid ob- 
tained by adding a few drops of nitrate of silver to 
aqueous iodine loses go per cent of its bleaching power 
in five minutes. 



HYPOIODOUS ACID AND HYPOIODITES.* 
By R. L. TAYLOR, F.C.S. 

The author confirms and extends the observations of 
Schonbein, using, as he did, an aqueous solution of iodine. 
When a little alkali is added there is pradtically no iodate 
formed, from 90 to 95 per cent of the iodine undergoing 
the readtion represented by the equation — 

2KOH + Ia = KI+KOI-j-HaO. 
This is proved by the bleaching adlion upon a standard 
Bolution of indigo, and also by Schwicker's method of 
decomposing the hypoiodite by a bicarbonate or by car- 
bonic acid. 

The solution bleaches indigo much more rapidly than 
chlorine or hypochlorites, but does not bleach litmus. It 
gives a precipitate with cobalt nitrate which blackens on 
standing, and an immediate brown precipitate with man- 
ganous salts and lead salts. Stronger solutions are 
obtained by using iodine water containing a little sus- 
pended iodine. All the solutions are decomposed com- 
pletely by boiling for three or four minutes. The author 
concludes that the readtion represented above, as Walker 
and Ray have also recently stated, is a balanced one. 
He has repeated Lunge and Schoch's experiments, who 
obtained, by the adlion of iodine upon lime in presence of 
comparatively little water, a bleaching liquid which stood 
being boiled for hours without being decomposed. He 

* Summary of a Paper read at the Manchester Literary and Philo 
■ophical Society, February gtb, 1897. 



OPENING UP OF SILICATES. 
By P. JANNASCH. 

For this purpose the author uses pure lead silicate, and 
finds it satisfadtory. He proceeded from Bong's pro- 
posal to use lead oxide for this purpose, supported upon 
the favourable experiments which he made in concert 
with J. Locke in determining the water in topaz. Jannasch 
proposes to mix the silicate (freed from organic matter, if 
necessary by ignition) with from ten to twelve parts of 
lead carbonate, and heat it in a platinum crucible, 52 to 
53 m.m. in height, and 45 ra.m. wide at top, for from 
^fteen to twenty minutes at first, with a flame of about 
an inch in height. It is then heated to fusion, but the 
crucible must not be red-hot for more than one-third of 
its height. The fusion is continued for ten to fifteen 
minutes. Care must be taken that the flame does not 
smoke in order to avoid any redudtive adtion. The crucible 
is taken diredtly from the flame and plunged into cold 
distilled water. The melt is removed from the crucible 
by gentle tapping and squeezing, and decomposed with 
nitric acid, and finally evaporated repeatedly to dust- 
dryness with concentrated nitric acid, and the residue is 
taken up with 10 c.c. of concentrated nitric acid, diluted 
with 75 to 100 c.c. of water, heated on the water-bath for 
fifteen minutes, filtered and washed. 

The filtrate is mixed with abundance of hydrochloric 
acid ; after settling the lead chloride is sucked off and 
washed with hydrochloric acid (i vol. concentrated acid 
+ I vol. water). The filtrate is evaporated down (to 
expel nitric acid) with 30 c.c. hydrochloric acid (i : 4) 
and as much water. The residue of the lead chloride is 
filtered off and quickly washed with cold water. The 
traces of lead left in the filtrate are precipitated with sul- 
phuretted hydrogen. The hydrogen sulphide is then 
entirely removed from the filtrate. — Zeit. Anorg. Chemie, 



98 



A ction of Wagner* s Reagent upon Caffeine. 



I CbbmicalNbws, 

1 Feb. 26, 1897. 



A SENSITIVE SIMPLE REACTION FOR 

NITROUS ACID. 

By Prof. Dr. E. RIEGLER. 

We introduce into a small test-tube about 2 or 3 centi- 
grms. of crystallised naphthionic acid, and from 5 to 6 
c.c. of the liquid to be examined for nitrous acid, shake 
up well, add 2 or 3 drops of concentrated hydrochloric 
acid, shake up thoroughly for a minute, and allow from 
20 to 30 drops of ammonia to flow slowly into the test- 
tube whilst held in a slanting position ; when there 
appears at the surface of contaA of the liquids a rose- 
coloured ring, even if only traces of nitrous acid are pre- 
sent. If we shake up the entire liquid it becomes rose- 
coloured or deep red, according to the quantity of the 
nitrous acid. 

As very dilute solutions of naphthionic acid have a 
violet-blue fluorescence, it is advantageous to examine 
the colour by transmitted light. 

The rea&ion consists herein, that the naphthionic acid 
is converted by the nitrous acid into diazo-naphthalin 
sulphonic acid, which forms with another mol. of naph- 
thionic acid, and with ammonia a colouring matter which 
determines the rose colouration. 

In rain and drinking waters the nitrous acid can be 
very finely shown by means of this rea&ion. The 
detedlion of nitrites in saliva is extremely instructive. To 
this end we dilute the saliva with five times its volume 
of pure distilled water, filter, and treat 5 or 6 c.c. of the 
filtrate as above diredted. 

Traces of nitrous acid may in like manner be dete&able 
in urine. — Zeit. Analyt. Chemie. 



WORKING UP URANIUM RESIDUES. 
By A. GOWALOWSKI. 

In this paper I formerly described a method for working 
up uraninm phosphate residues. Supported upon Laugier's 
observations I used ammonium carbonate for dissolving 
hydrated uranium phosphate, but I have now abandoned 
this method in favour of sodium carbonate (ammonia 
soda), which is both cheaper and has a greater solvent 
power. By introducing the uranic precipitate into a 
strong solution of ammonia soda, I dissolve the uranium 
phosphate, filter, and add rather more ferric chloride than 
is necessary to take up all the phosphoric acid, and filter 
again, when iron phosphate and ferric hydrate remain, 
which are washed with water. I treat the entire filtrate 
in small portions with magnesia mixture as long as there 
appears a turbidity of ammonio-magnesium phosphate, 
whereby any residues of phosphoric acid are separated. 
From the solution precipitate uranium oxide with sodium 
carbonate ; filter after standing for twenty-four hours, and 
dissolve either at once in acetic acid or acidify previously 
with hydrochloric acid, boil to expel carbonic acid, pre- 
cipitate with ammonia, colledt the ammonia-uranic oxide 
on the filter, wash, and dissolve in acetic acid or in nitric 
or hydrochloric acid,— Zeit. Analyt. Chemie. 



Isomerism of Stru(!\ure and of Rotatory Power. — 
Ph. A. Guye and J. Guechgorine. — It results from these 
researches that we know at present three series of propylic 
isomers and three series of butylic isomers among the 
derivatives of adtive amylic alcohol. If we take account 
of the decreasing charader of the rotatory powers in each 
of these series, we conclude that in all these series the 
propylic group behaves as heavier than the isopropyl 
group, and that the isobutyl group behaves as heavier 
than normal butyl, which in turn adls as heavier than 
secondary butyl. — Comptes Rendus, cxxiv., No. 5. 



ON THE ACTION OF WAGNER'S REAGENT 

UPON CAFFEINE, AND 

A NEW METHOD FOR THE ESTIMATION 

OF CAFFEINE.' 

By M.GOMBERG. 
(Concluded from p. go). 

Bitimation of Caffeine. 
All the methods for the estimation of caffeine depend 
upon the extraction of the alkaloid by an immiscible sol- 
vent from either a dry residue or from its solution in 
water. But Spencer (Journ. Anal. Chem., iv., 390, i8go) 
has recently shown how difficult it is to remove the alka- 
loid from its solution in water. According to him, it is 
necessary to shake out the liquid at least seven times with 
chloroform, in order to remove caffeine quantitatively. It 
is usually stated that caffeine does not form any stable 
salts in a watery solution, and consequently it can be 
shaken out with immiscible solvents from either alkaline 
or acid solutions. But this is only relatively true, as will 
appear from the following illustrations. 1*0085 grms. of 
caffeine were dissolved in 60 c.c. of sulphuric acid (i : 10), 
and this solution was repeatedly shaken out with chloro- 
form, 25 c.c. at a time. 

10 consecutive portions of chloro- 
form gave a total of 0'35i4 grm. caffeine. 

3 additional portions of chloro- 
form made a total of 0*4^59 ft M 

3 more additional portions of 

chloroform made a total of .. 0*5034 „ „ 

The extreme delicacy of the test for caffeine by means 
of Wagner's reagent has suggested the possibility of 
applying this reagent for the quantitative estimation of 
the alkaloid. Its successful application necessitates, of 
course, a solution of the alkaloid free from other sub- 
stances that are precipitated by, or absorb iodine, — a con- 
dition requisite in the estimation of any base by means of 
Wagner's reagent. This method gives very satisfactory 
results, as nearly theoretical as could be expedted. I am 
indebted for the analytical data of the subjoined table to 
Mr. James W. Knox, holder of the Stearns' Fellowship in 
the School of Pharmacy. The method of procedure em- 
ployed by us was prai^ically the same as that used by 
Kippenberger. Definite volumes of acidulated solutions 
of caffeine were precipitated with a known volume of 
iodine in potassium iodide. After complete precipitation 
an aliquot portion of the supernatant liquid was obtained, 
either by decantation or filtration, and the excess of 
iodine was estimated by titrating against a tenth normal 
solution of sodium thiosulphate. The precipitation is 
best performed in a tall test-tube on foot, and the solution 
for titration is removed dire(5tly by immersing the end of 
the burette into the liquid and applying sudion at the 
upper end. When it is desirable to filter off an aliquot 
portion, a filter of glass-wool and asbestos gives very satis- 
fadtory results. 

We have tested the method on solutions of caffeine 
acidulated with sulphuric acid, the solutions being of dif- 
ferent strengths, namely, containing 0*25 per cent of 
caffeine, 0*50 per cent, 0*75 per cent, and I'oo per cent 
respeiaively. We have varied in different series of experi- 
ments the amounts of Wagner's reagent, employing just 
the theoretical quantities, a small and large excess above 
that, as well as quantities below those required by the 
theory. Columns I., II., III., and IV., give the results 
obtained by allowing the solutions to stand for an hour 
before decanting an aliquot portion for titration ; column 
V. shows the results obtained when the liquid for titra- 
tion was filtered off within five minutes after the addition 
of Wagner's reagent. The results are calculated on 
the basis that the periodide has the composition 

* From the Journal of the American Chemical Society, xviii., No. 4. 



OBBMICAL NBWBiI 

Feb. t6, 1897. f 



London Water Supply, 



90 



o 

c ? 
H Si. 

»< O 



U3 A 



a* 



Bg 

■o -1 



VI 

+ 



o o ? 
00 to a 



vo SJ) 

to S 2 
*- 3SJ 



O O' 



o „ 



8 



o '0 
VO o 2 

00 1 n 



■°5 
n pa 



a'ffq 






S " 
" o 

-O D 1-1 



(To' 
a o 



q Hi 

M St 



O •]] 

M 2 






00 ^ 



VO RS" 
■fc So 

O D 
H P 



O 1) 

M 



00 32 



M p 



si 

o o 
n a 

2.0 



f* 



10 K- 

8 s 



to o ;; 

• " s 
oog.Sj 



O O M 



n g 

n S' 

a a 
" o 

P s 

cPa 
<» o 



C8H10N4O2. HI. I4. The amount of alkaloid is calculated 
from the amount of iodine used up, by the formula — 

4I : C8H10N4O2 : : 506 : 194 ; 
i.e., one part of iodine represents 03834 part of caffeine. 
Or, I c.c. tenth normal iodine =0*00485 grm. caffeine. 

The results presented below show that the estimation 
of caffeine by this method is very exadt. The best results 
are obtained when iodine is in considerable excess, as is 
evident from the figures obtained where one and one-third 
and twice the theoretical quantities of Wagner's reagent 
were used. All the results in the table were obtained on 
solutions of caffeine acidulated with sulphuric acid, the 
acidulation being tolerably strong, about i c.c. of the con- 
centrated acid to 50 c.c. of the liquid. Experiments upon 
the influence of the acid indicate that a large excess of 
sulphuric acid interferes to some extent with the readtion. 
The amount of recovered caffeine fails as low as 95 per 
cent of the quantity taken, when 4 c.c. of the concen- 
trated acid to 50 c.c. of the liquid are used. The results 
are also not very uniform and concordant. The fadl that 
the precipitation of caffeine by Wagner's reagent is more 
delicate in presence of hydrochloric acid than any other 
acid would make it advisable to employ that acid in 
quantitative estimation of the base by iodine. 

This method could easily be employed for the estima- 
tion of the alkaloid in caffeine-bearing drugs. Of course, 
it is necessary to have the final solution of the alkaloid 
in water as free as possible from other substances that 
may be precipitated by Wagner's reagent. The estima- 
tion of caffeine by this method is likely to give higher re- 
sults than have hitherto been obtained. The following 
procedure is recommended :* — The drug is thoroughly 
digested with water for some time, by the aid of heat, 
cooled, and made up to a definite volume, and filtered. 
An aliquot portion of the filtrate is treated with lead 
acetate, the precipitate allowed to settle and filtered. 
The whole of the filtrate, or a given portion of it, is treated 
with hydrogen sulphide to remove the lead, and filtered. 
This filtrate, after boiling off the hydrogen sulphide, is 
divided into two equal portions, and each treated with a 
definite volume of the standard iodine solution, — the first 
portion without the addition of any mineral acid, the 
second with the addition of hydrochloric or sulphuric acid. 
After five to ten minutes' standing the excess of iodine is 
estimated in each of the two solutions, as described 
above. The first portion, containing no other but some 
acetic acid, serves to indicate whether the filtrate from 
the lead sulphide contains any other materials besides 
caffeine that are likely to be precipitated by Wagner's 
reagent, — for caffeine itself is not precipitated by it even 
in presence of tolerably strong acetic acid. If any absorp- 
tion of iodine be found in the first portion, then that 
quantity is to be subtradled from the amount of iodine 
taken up by the second portion ; the difference represents 
the iodine used up in the formation of the periodide of 
caffeine. The amount thus used up multiplied by 03834 
gives the amount of caffeine in that particular portion of 
the liquid. 

LONDON WATER SUPPLY. 
Report on the Composition and Quality of Daily 
Samples of the Water Supplied to London 
FOR the Month Ending January 31ST, 1897. 

By WILLIAM CROOKES, F.R.S., 

and 

PROFESSOR DEWAR, F.R.S. 

To Major-General A. De Courcv Scott, R.E., 
Water Examiner, Metropolis Water Act, 1871. 

London, February nth, 1897. 
Sir, — We submit herewith, at the request of the 
Diretflors, the r esults of our analyses of the 182 samples 
• These direAions aie in part given by Spencer, 1890 (Joum. 
Anal. Chem., iv., 390). 



100 



Report of Committee on A tomk Weights. 



j Cbbmical Nbws, 
\ Feb. 26, X897. 



of water colledted 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. ist to Jan. 31st 
inclusive. The purity of the water, in respedt to organic 
matter, has been determined by the Oxygen and Com- 
bustion processes; and the results of our analyses by 
these methods are stated in Columns XIV. to XVIII. 

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

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 all were found to be clear, 
bright, and well filtered. 

The rainfall at Oxford during the month still shows a 
small deficiency, the average fall for the last thirty years 
is 2*i6 inches, the aftual fall in January was i"85 inches, 
making a deficiency of o'3i inch ; it has been pretty fairly 
distributed through the month, the greatest fall being 0*58 
inch on the 8th. 

Our ba^eriological examinations have been, and will 
in future be, conduced on a much larger scale ; this month 
105 samples were examined, with the following results : — 

Colonies 
per c.c. 

Thames water, unfiltered 6409 

Thames water, from the clear water wells of 
the five Thames-derived supplies., highest 

Ditto ditto lowest 

Ditto ditto .. (45 samples) mean 

New River water, unfiltered 

New River water, from the Company's clear 
water well 

River Lea water, unfiltered 1460 

River Lea water from the East London Com- 
pany's clear water well ao 

With regard to the above results, it is our duty to say 
that one very exceptional result was also recorded during 
the month, viz., on the 14th, when one of the wells was 
found to contain, in our judgment, too great a number of 
microbes, having regard to the usual high quality of the 
filtered supply. A serious warning of the abnormal bac- 
teriological condition of the water was immediately com- 
municated to the Engineer of the Company, and the next 
sample of water, taken within 48 hours, had resumed its 
normal condition. 

We are, Sir, 

Your obedient Servants, 

William Crookes. 
James Dewar. 



75 

4 

30 

1420 

37 



THIRD ANNUAL REPORT OF COMMITTEE 

ON ATOMIC WEIGHTS. 

RESULTS PUBLISHED DURING 1895.* 

By F. W. CLARKE. 

(Continued from p. 90). 

Tellurium. — The determinations of atomic weight by 
Staudenmeier {Ztschr. Anorg. Chem., x., 189; calcula- 
tions based upon = i6 and H = i'0032) all start out from 
telluric acid, H2Te04-2H20, which had been purified by 
repeated crystallisation. Two essentially different 
methods were adopted. First, telluric acid was dehy- 
drated, and reduced to TeOa by heating. Secondly, 
telluric acid was reduced by heating in hydrogen to 
metallic tellurium, finely divided silver being mixed with 
the acid to retain the tellurium by preventing volatilisa- 
tion. In four e xperiments. TeOa was reduced to Te in 
* Read at the Cleveland Meeting, December 31, 1895. From the 
Journal of the American Chemical Society, xviii., No. 3. 



the same manner. The weights and results may be 
classified as follows for the convenience of comparison :^ 

TeOa : Te. 



TeO,. 


Loss on reduA 


ion. Atomic weight of Te 


o'giyi 


0-1839 


127-6 


1-9721 


0-3951 


127-7 


2-4115 


0-4835 


127-6 


I-OI72 


0-2041 


127-5 




Telluric Acid : 


TeOj. 


Telluric acid. 


Loss. 


Atomic weight of Te 


1-7218 


0*5260 


127-2 


2-8402 


0-8676 


127-1 


4-0998 


1-2528 


127-1 


3-0916 


0-9450 


12705 


I'ii38 


0-3405 


127-0 


4*9843 


1-5236 


127-05 


4-6716 


1-4278 


127'X 




Telluric Acid 


Te. 


Telluric acid 


Loss. 


Atomic weight of Te 


1-2299 


0-5471 


1273 


I-OI75 


0-4526 


127-3 


2-5946 


I -1549 


127*2 



There is a good discussion in the paper as to the pos- 
sible cause of error in these determinations, and also con- 
cerning the place of tellurium in the periodic system. 
Staudenmeier upholds the homogeneity of tellurium as an 
element, as against the supposition that it is a mixture. 

Some years ago Brauner, in an elaborate paper upon 
tellurium, sought to show that the ordinary element was 
a mixture of true tellurium with a higher homologue of 
atomic weight 214. He now (Jourrt. Chem. Soc, Ixvii., 
549) concludes that this is very improbable, and suggests 
that tellurium may contain a homologue of argon, of 
atomic weight 130. For this supposition no evidence is 
given apart from the abnormality of the atomic weight, 
which should fall below that of iodine. 

Yttrium. — The atomic weight of this metal has been 
re-determined by Jones {Am. Chem. yo«r»., xvii., 154; 
calculations based upon O = 16 and H = 1*0032), 
who started out with material purified by Rowland's pro- 
cess; that is, by precipitation with potassium ferro- 
cyanide. First, oxide was converted into sulphate; and 
secondly, sulphate was transformed to oxide by calcination. 
The weights and results were as follows : — 

First Method. 



Y,0,. 


Y,(SO.)a. 


Atomic weight of Y. 


0-2415 


0-4984 


88-89 


0*4112 


0*8485 


8892 


0*2238 


0-4617 


88-97 


0-3334 


0-6879 


88*94 


0-3408 


0-7033 


88*90 


0-3418 


0-7049 


89*05 


0*2810 


0-5798 


88*94 


0*3718 


0-7803 


88-8g 


0*4379 


09032 


8g*o2 


0*4798 


0-9901 


88-gi 




Mean.. 


.. 88*94 




Second Method. 




Y,(SOJ,. 


Y,o,. 


Atomic weight of Y 


0-5906 


0-2862 


88*91 


0-4918 


0-2383 


88*8g 


0-5579 


0-2705 


89*03 


0-6430 


0*3117 


88*99 


0-6953 


0-3369 


88*89 


1-4192 


0-6880 


88*99 


0-8307 


0-4027 


88-99 


07980 


0-3869 


89-02 


0-8538 


0-4139 


88-99 


1-1890 


0-5763 


88-96 



Mean.. 



88-97 



Chbuical News, 
Feb. 26, 1897. 



Determination of Atomic Masses by the Electrolytic Methods 101 



These determinations are probably the best hitherto 
made, although they have been briefly criticised by Dela- 
fontaine (Chem. News, Ixxi,, 243), who prefers the lower 
value obtained by himself, Y=87"3. Delafontaine re- 
affirms the existence of phillipium, and regards gado- 
linium as identical with decipium. Jones (Chem. News, 
Ixxi., 305), in a brief rejoinder, defends his own work, and 
urges that Delafontaine has failed to show wherein it is 
defective. 

The Cerite Earths, — Papers upon this subjefthave been 
published by Schiitzenberger and by Brauner, In his 
first communication, Schiitzenberger {Compt. Rend,, cxx., 
663) deals with cerium, which had been freed from 
lanthanum and " didymium " by fusion of the mixed 
nitrates with saltpetre. The yellowish white cerium 
oxide was converted into cerium sulphate, which was 
dried at 440°. In this salt, with special precautions, the 
sulphuric acid was estimated by precipitation with barium 
chloride. One hundred parts of cerium sulphate gave 
I23'30 of barium sulphate. Hence, Ce = i39"45, according 
to Schiitzenberger's calculations. Re-computing with — 

= 16, S=32'07, and Ba= 137*43, 
Ce = 139-96. 

In a second paper {Compt. Rend., cxx., 962) Schiitzen- 
berger describes the results obtained by the fradionation of 
cerium sulphate. Preparations were thus secured giving 
oxides of various colours, such as canary-yellow, yellowish 
rose, reddish, and brownish red. These, by the synthesis 
of the sulphates, the barium sulphate method, &c., gave 
varying values for cerium, ranging from I35'7 up to i43*3. 
Schiitzenberger concludes that the cerium sesquioxide 
from cerite contains small quantities of another earth of 
lower atomic weight. In a third paper (Compt, Rend., 
cxx., 1143) he continues the investigation with the other 
cerite earths. For the didymiums he finds a range in 
atomic weight from i37*5 to i43'5 approximately. 

Brauner's paper (Chem. News, Ixxi., 2S3) is partly a 
reclamation of priority over Schiitzenberger, and partly a 
preliminary statement of new results. In his earlier work 
he found that cerium oxide was a mixture of two earths ; 
one white, the other flesh colour with a tinge of orange, 
and atomic weights for the contained metal of 140*2 and 
14572 respectively. In his later researches Brauner 
fra&ionates his material by several methods. One con- 
stituent obtained from cerium oxide is a dark salmon- 
coloured earth, the oxide of a metal which he calls " meta- 
cerium." The other constituent he calls cerium. Pure 
cerium oxalate by Gibbs's permanganate method gave 
29*506 and 29*503 per cent of cerium sesquioxide with 
4^'934*per cent of cerium dioxide, Hence, Ce = 139*91, 
or, with a slight correction, Ce = i40'oi. This is not far 
from Schiitzenberger's value. 

(To be continued). 



THE DETERMINATION OF ATOMIC MASSES 

OF SILVER, MERCURY, AND CADMIUM, 

BY THE ELECTROLYTIC METHOD.* 

By WILLETT LEPLEY HARDIN. 

(Concluded from p. 93). 

Part III. {continued). 

First Series. 

Experiments on Cadmium Chloride. 

Dumas and Bucher have both determined the ratio of 

cadmium to chlorine in cadmium chloride. The results 

given for the atomic mass of cadmium by the latter ex- 

♦ Contribution from the John Harrison Laboratory of Chemistry, 
No. 13. From the author's thesis presented to the Faculty of the 
University of Pennsylvania for the degree of Ph.D.— From the 
Journal oj the American Chemical Society, xviii., p. ggo. 



perimenter are almost four-tenths of a unit higher than 
those given by the former. 

Preparation of Cadmium Chloride, 
Hydrochloric acid was purifled by first passing chlorine 
through the commercial C. P. acid to remove any sul- 
phur dioxide ; the excess of chlorine was removed by a 
current of carbon dioxide. The acid was then distilled 
from calcium chloride and the hydrochloric acid gas col- 
ledled in pure water. Pure metallic cadmium was then 
dissolved in the acid and the solution evaporated to crys- 
tallisation. The crystals of cadmium chloride were re- 
moved from the liquid and thoroughly dried. The 
material was then placed in a hard glass combustion-tube, 
similar to that used in the distillation of metallic cadmium, 
and carefully sublimed in a current of dry carbon dioxide. 
The first and last portions of the sublimate were rejedted. 
The middle portion, which consisted of pearly leaflets, 
was placed in a weighing tube and kept in a desiccator. 
As only a small quantity of the material could be sub- 
limed at a time, the different analyses were made from 
different sublimations. 

Mode of Procedure. 
A weighed portion of the cadmium chloride was dis- 
solved in a little water in a platinum dish, a slight excess 
of potassium cyanide was added and, after diluting to 
200 c.c. with pure water, the solution was electrolysed. 
Before interrupting the current, the liquid was syphoned 
from a dish in a manner already outlined in the experi- 
ments on silver. The metallic deposit was washed 
several times with boiling water and carefully dried. The 
strength of the current and time of aClion were as fol- 
lows : — 

Time of aftion. Strength of current. 

1 2 hours,. .. N.Dioo=o*i ampere. 
4 „ .. .. N.Dioo=o'i5 „ 

4 N.Dioo=o*3o „ 

The cadmium was thrown down as a dense white 
deposit. Ten results on cadmium chloride reduced to a 
vacuum standard on the basis of — 

3*3 = density of cadmium chloride, 
8*55 = ,, metallic cadmium, 

21*4 = ,, platinum dish, 

8'5 = II weights, 

and computed for the formula CdClj, assuming 35*45 to 
be the atomic mass of chlorine, are as follows : — 



I 
2 
3 
4 
5 
6 

7 
8 

9 
10 



Weight 

of CdCla. 

Grms. 

0*43140 
0*49165 
0*71752 
0*72188 
0*77264 
081224 
0*90022 
1*02072 
1 *26322 
1*52344 

Mean .. 

Maximum 

Minimum 



Weight 
ofCd. 
Grm. 

0*26422 
0*30112 
0*43942 
0*44208 
0*47319 
0*49742 

0*55 135 

0*62505 

0*77365 

0*93314 

= 112*038 
. = 112*078 
. = 112*002 



Atomic mass 
of cadmium. 



1 12*054 
112*052 
112*028 
112*021 
112-036 
112*023 
112*041 
112*002 
1X2*041 
112*078 



Difference ,. = 0-076 
Probable error = ^0*005 
From the total quantity of material used and metal 
obtained, we have 112040 for the atomic mass of 
cadmium. 

Second Series. 
Preparation of Cadmium Bromide. 
The bromine used in this series was purified as out- 
lined in the experiments on mercuric bromide. The 



io^ 



Determination of Atomic Masses by the Electtolytic Method. {^^F^b^eM*?'"' 



cadmium bromide was prepared by allowing bromine water 
to aa on metallic cadmium for several days at the ordinary 
temperature. When the adlion was complete, the solu- 
tion was filtered and evaporated to crystallisation. The 
crystals of cadmium bromide were removed from the 
liquid and thoroughly dried. The material was then 
placed in a hard glass combustion-tube and carefully sub- 
limed in a current of dry carbon dioxide. The first and last 
portions of the sublimate were rejeifled. The middle por- 
tion was removed from the tube, placed in a weighing 
bottle and kept in a desiccator. The produdl obtained in 
this way consisted of a crystalline pearly leaflet which 
dissolved immediately in water without leaving a residue. 

Mode of Procedure, 
The method of operation was the same as for cadmium 
chloride. A weighed portion of the material was dis- 
solved in a little water in a platinum dish. A slight ex- 
cess of potassium cyanide was then added, and after 
diluting to 200 c.c. the solution was eledtrolysed and the 
resulting metal weighed. The strength of current and 
time of aftion were the same as for cadmium chloride. 

Ten observations on cadmium bromide reduced to a 
vacuum standard on a basis of — 

4'8 = density of cadmium bromide, 
8*55 = II metallic cadmium, 

21 '4 = ,, platinum dish, 

8'5 = I, weights, 

and computed for the formula CdBrj, assuming 79*95 to 
be the atomic mass of bromine, are as follows : — 









Atomic mass 




Weight of CdBr,. 


Weight of Cd. 


of cadmium. 




Grm. 


Grm. 




I 


o'57745 


o*237go 


112*031 


2 


076412 


0-31484 


112-052 


3 


0-91835 


0-37842 


112-067 


4 


1-01460 


041808 


112-068 


5 


1-15074 


0*47414 


112-053 


b 


I -24751 


0-51392 


ll2-oig 


7 


1-25951 


0-51905 


122*087 


8 


1*51805 


0-62556 


112*076 


9 


1-63543 


0-67378 


112*034 


10 


2-15342 


0-88722 


112*041 




Mean .. 


.. =112053 






Maximum 


.. = 112*087 






Minimum 


.. = ii2*oig 





Difference .. = o*o68 
Probable error = ^^0*005 

From the total quantity of material used and the meta' 
obtained, Cd = 112*053. 

Third Series. 

In these experiments an attempt was made to deter- 
mine the ratio of the atomic mass of cadmium to that of 
silver by allowing the same eledlric current to pass suc- 
cessively through solutions of the two metals and weighing 
the resulting deposits. The arrangement of apparatus 
and the details of the method were described under the 
mercury-silver series. The results were not as satisfac- 
tory as the corresponding results obtained for mercury. 
A large number of determinations were made with cur- 
rents of different strength and solutions of different con- 
centration, but the results were, in most cases, far below 
those obtained in the first two series. A current which 
deposited about twelve-hundredths of a grm. of silver per 
hour seemed to give the best results. From all the ob- 
servations, five results were seleded which differed only 
about one-tenth of a unit from those of the first two 
series. Results selected in this way are entitled to but 
little weight, and perhaps should not be used in deter- 
mining the general mean of all the observations. 

Computed on the basis of 107*92 for the atomic mass 
of silver, the only admissible results are as follows : — 





Weight of 
Grm. 


Weight of 
Cd. 
Grm. 


Atomic mass of 
Cadmium. 


I 

2 

3 
4 
5 


0-24335 
0-21262 

0-24515 
0-24331 
0-42520 


0-12624 
0-11032 
0-12720 
0*12616 
0-22058 




1 1 1-928 
iii*ggi 
111-952 
iii-gi6 
iii-g7i 




Mean .. 
Maximum . 
Minimum . 


= III 
= 111 
= III 


952 
991 
gi6 






Difference . 


= 


07s 





This method was discussed under mercury. The prob- 
able sources of error pointed out there apply equally well 
in the case of cadmium. Until the large variations can 
be accounted for and the difficulties overcome, the method 
must be regarded as unsatisfadlory. 

Summary. 

Inasmuch as but one method of analysis has been used 
throughout this work, it is useless to discuss it here. The 
advantages and objections pointed out under silver apply 
also to cadmium. 

In summing up the work on cadmium, equal weight 
must be given to the first two series. The last series 
must be considered alone, and all that need be said of it 
is, that the results obtained for the atomic mass of cad- 
mium never exceeded 112. In the corresponding series 
on mercury, the variations were in both diredtions from 
200. 

The general mean of the first two series calculated from 
the separate observations is — 

Atomic mass of Cd. 

First series = 112*038 

Second series .. .. = 112053 



General mean 



= 112*0455 



From the total quantity of material used and metal 
obtained we have — 

Atomic mass of Cd. 

First series = 112-040 

Second series .. .. = 112*053 



General mean 



= 112-0465 



Combining this with the first general mean we have 
112*046 as the most probable result of all the work, for 
the atomic mass of cadmium. This result is lower than 
those obtained by Huntington and Bucher, but agrees 
very closely with the results obtained by von Hauer, 
Dumas, Lensen, Jones, and Lorimer and Smith. 

I wish here to express my sense of gratitude to 
Professor Edgar F. Smith, at whose suggestion this work 
was undertaken and under whose personal supervision it 
was carried out. 



Radio-photography of the Soft Parts of Man and 
of the Lower Animals. — MM. Remy and Contremoulin. 
We have the honour of presenting to the Academy a new 
result of our researches on the application of the X rays 
to anatomical studies. By the aid of chemical prepara- 
tions on the bodies of men and frogs, we have been able 
to place the muscles, the ligaments, and the tendons in 
such a state that they have yielded radio-photographic 
images. The muscle projedted shows a dark tint, but 
within the limits thus indicated we perceive dark traits 
which pertain to the muscular bundles. The muscle is 
thus masked by bundles of longitudinal striae very dis- 
tiniftly limited. In the frog, prepared by the same means, 
the muscles are fully visible. In this animal we have 
obtained an image of the crystalline lens and of the 
coatings of the eye. — Comptes Rendus, cxxiv., No. 5. 



CHBMICAL NbWB.I 

Feb. 26, 1897. I 



Electric Shadows and Luminescence, 



103 



ELECTRIC SHADOWS AND LUMINESCENCE.* 
By Prof. SILVANUS P. THOMPSON, D.Sc, F.R.8., M.R.I. 

The early days of the year 1896 were marked by the 
announcement telegraphed from Vienna to the eifedt that 
Professor Rontgen, a man whose name, though little 
known outside the world of science, was well known and 
highly esteemed by those who were mitiates in physics, 
had discovered the existence of rays of a new and extra- 
ordinary kind. Taking a Crookes tube, excited of course 
by a proper eleftric spark, and covering it up within a 
case of black cardboard, he found it to produce in the 
surrounding space some entirely unexpedled effedts. 
Black cardboard is impervious not only to ordinary light 
and to radiant heat, but also to all those other known 
kinds of invisible light beyond the violet end of the 
spedrum, known as adlinic waves, which are such aftive 
agents in the produdtion both of fluorescence and of 
photographic actions. Yet the invisible emanations of 
the Crookes tube, which passed freely through the opaque 
cardboard, were found by Rontgen to be capable of 
revealing their presence in two ways. In the first place 
he had seen them to projedt shadows upon a luminescent 
screen of paper coated with the highly fluorescent sub- 
stance called platino-cyanide of barium, and in the second 
place he had been able to photograph these shadows by 
letting them fall upon an ordinary photographic plate. 
The discovery was singular. It revealed the existence 
of a remarkable and hitherto unexpected species of radia- 
tion. It added another to the many puzzling phenomena 
attendant upon the discharge of eledtricity in vacuo. 
It proved that something which in the ordinary sense in 
which those terms are used is neither light nor elec- 
tricity was generated in the Crookes tube, and passed 
from it through substances opaque alike to both. 

But that which took the imagination of the multitude 
by storm, and aroused an interest the intensity the like of 
which has not been known to be aroused by any other 
scientific discovery in our times, was not the fadt that 
Professor R5ntgen had seen luminescent shadows from a 
Crookes tube, or had obtained a photograph of those 
shadows ; it was the entirely subsidiary and comparatively 
unimportant point that to these mysterious radiations 
flesh is more transparent than bone. 

Let me begin by showing you as a first experiment that 
same fadt which Rontgen announced of the produdtion of 
luminescent shadows by these invisible rays. Before you 
there stands a Crookes tube, of the most modern kind.f 
for this particular purpose. We have here an indudtion 
coilj capable of giving 6-inch sparks, with which we can 
Bend eledtric discharges through the tube, illuminating it 
with its charadteristic golden-green glow. I now cover 
over the tube and exclude all ordinary light, not with a 
box of black cardboard but with a black velvet cloth. 
And now in the darkness I am able to show you how on 
a sheet of paper covered with the highly fluorescent 
platino-cyanide of barium — the well-known substance 
which Rontgen himself was using — the shadows of 
objedts placed between. See how this sheet shines in 
the light of the tube transmuting the invisible radiations 
into visible light. I hold my purse behind the screen — 
you see the shadow of the metal clasp, and of the metal 
contents (two coins and a ring), but you see not the 
shadow of the leather purse itself, for leather is trans- 
parent to these rays while metal is opaque. I hold my 
hand behind and you see — or at least those of you who 
are within a few yards of me — the shadow of my hand, 
or rather of the bones of my hand, surrounded by a fainter 
shadow of the almost transparent flesh. 

* A LeAure de ivered at the Royal Institution oi Great Britain 
Friday, May 8, i8g6. 

t A Crookes " focus " tube (Jackson pattern), conatruAed by 
Messrs. Newton and Co , of Fleet Street, London. 

t An Apps coil capable of giving sparks 25 centimetres in length, 
but on this occasion excited with only j cells, giving sparks about 6 
inches in length. 



Now the second fa^ that Rontgen announced was that 
these same rays which escape through the opaque cover- 
ing and excite fluorescence are also capable of taking 
photographic impressions of the shadows. There is 
nothing whatever new about this part of the subjedt: it 
is the old photograph ; there is no '• new photography." 
Here is a common camera back, and here inside it is a 
photographic dry-plate — quite a common dry-plate, such 
as has been known for ten years. This plate is covered 
with a black card, so that it may not become fogged by 
the light of the room when I draw the slide. All I have 
to do is to lay it upon the table below the Crookes tube 
so as to cast the shadow upon it, and after due exposure 
develop the plate in the ordinary well-understood way. 
Now it may be interesting to see the proof of the fadt that 
bone is less transparent than flesh. So, with your per- 
mission, I will ask my little daughter to have her hand 
photographed. (Experiment made). 

At the time of Rontgen's announcement, the exposure 
required with the Crookes tubes that were then in exist- 
ence was from twenty minutes to, I think, two or three 
hours. Very shortly improvements were made ; and with 
these modern tubes one minute is quite sufficient for an 
exposure. Indeed, one minute is too much for many 
objedts. I have not previously tried this particular tube, 
though I judge by its appearance that it is in good con- 
dition. As soon as the exposure of one minute is over 
we will have the plate taken into the dark room and 
developed in the ordinary way ; and when it is developed 
we will have it brought back into this room and put into 
the lantern, that you may see what has been done. 

Now, while we are taking photographs, I may as well 
take a second to illustrate another point. Rontgen 
investigated in the most careful and elaborate way the 
relative transparency of different materials for these 
mysterious rays. He noticed that wood, and many sub- 
stances which are opaque to ordinary light, are trans- 
parent to these rays ; whilst, on the contrary, several sub- 
stances that are transparent to light, such as calc-spar 
and heavy glass, are very opaque toward them. Many 
experimenters have examined this question of relative 
transparency. I devoted a day or two to the study of 
gems, and found that imitation rubies made of red glass 
are much more opaque than real rubies, and that paste 
diamonds are much more opaque than real diamonds. 
Real diamonds and rubies are indeed very transparent, and 
scarcely cast any shadows on the luminescent screen, 
though I have found diamond to be more opaque than an 
equal thickness of black carbon. There are laid upon 
this piece of card two rubies, one being only a glass ruby. 
There is also a row of four small diamonds. I will leave 
you to find out whether they are false or real. And then 
there are three larger diamonds, one of which is uncut 
and is a genuine South African stone. I lay them down 
upon a photographic plate and expose them to the 
Rontgen rays so that we may test their relative trans- 
parency. (The two photographs thus taken were pro- 
jedled upon the screen at the close of the ledture.) 

Amongst the things which Rontgen told us was the 
fadl that different kinds of glass are unequally transparent ; 
that lead-glass, for instance, is much more opaque than 
soda-glass, or potash-glass, or, indeed, any glass which 
does not contain a heavy metal like lead. He found that 
pradically the transparency was governed by the density ; 
that the heavy or the dense substances were the more 
opaque. There is now some reason to corredl that state- 
ment, though in the main as a first approximation it is 
perfedtly true. Professor Dewar has shown that you 
must take into account, not the density in gross, but the 
atomic weight. Taking any homologous series, for 
example, such as a number of sulphides, or oxides, or 
chlorides, that one which contains the atomically 
heavier metal will be the more opaque. Again, the 
bromide of sodium is more opaque than the chloride of 
the same metal, and the iodide is more opaque than the 
bromide. But as the correspondence between relative 



I04 



Electric Shadows and Luminescence, 



1 Chemical News, 
1 Feb. 26, 1897. 



opacity and molecular or atomic weight breaks down 
when we try to pass from one series of compounds to a 
different series, there is some reason to carry the matter 
to a further degree of approximation. We must go 
beyond the suggestion of atomic weight. The nearest 
approach to a law that I have been able to get at yet, on 
comparing tables of statistics, is that the transparency is 
proportional to the specific heat. For homologous series 
this is, of course, the same as saying that the trans- 
parency is inversely proportion to the molecular weight. 

Rontgen found all the heavy metals to be remarkably 
opaque, while light metals like sodium and aluminium, 
and even zinc, are remarkable for their transparency. 
Aluminium, which is opaque to every known kind of 
light, is transparent, even in sheets half an inch thick, to 
these rays. Lithium, the lightest of solid metals, and 
with an atomic weight 7 as against aluminium 27, is so 
transparent that I have not been able yet even to see its 
shadow. Of all liquids water is the most transparent, 
and it has the highest specific heat of all of them. 

Rontgen further found these rays to be incapable either 
of refradion by lens or prism,* or of reflection by any 
polished mirror. Refle(5tion there is in one sense, that of 
diffuse refieiftion, such as white paper exercises on common 
light. No lens can concentrate these rays ; they are also 
apparently incapable of being polarised. One difficulty 
in experimenting on these strange properties is that air 
itself adts as a turbid medium, reflecting back diffusely, as 
a smoky cloud would do for ordinary light, a portion of 
the rays. 

Finding that these radiations differed in so many 
ways from ordinary light, and while resembling 
and even surpassing ultra-violet rays in their strong 
adtinic properties, yet differed entirely from them in 
respe^ of the properties of refradtion, reflection, and 
polarisation, he named them " X rays." To judge by his 
own writing, he appeared to wish that they might prove 
to be longitudinal vibrations in the ether, the possibility 
of the existence of which has been a subjedt of specula- 
tion on the part of some of the most learned of mathe- 
matical physicists. Others have suggested that these X 
rays are transverse vibrations of a much higher frequency 
and shorter wave-length than any known kind of ultra- 
violet light. Others, again, see in them evidence that 
radiant matter {i.e., kathodic streams of particles) can 
traverse the glass of a Crookes tube, and regard them as 
material in their nature. Lastly, it has been suggested 
that they may be neither waves nor streams of matter, but 
vortex motions in the ether. 

To follow out the bearings of these speculations, as 
well as to trace the development of discovery, let us go 
back a little and consider what was the starting-point of 
Rdntgen's research. He was using a Crookes tube. It 
is one of the difficulties of my task to-night that I have 
to speak in the presence of him who is the master of us 
all in this subjedt of eledlric discharges in the vacuum 
tube. But to understand the discoveries of Crookes let 
us first witness a few experimental illustrations of the 
phenomena of eledtric discharges in vacuum tubes. Many 
of them have been known for half a century. We all 
know of the researches made in England by Gassiot, and 
by Varley and others, and the tubes of Geissler of Bonn 
are a household word. But there is one set of researches 
which deserves to be known far better than it is, that 
made by Dr. W. H. Th. Meyer, of Frankfort, whose pam- 
phletf I hold in my hand. In it he depidts a number of 
tubes in various stages of exhaustion, including one in 



* Perrin, in Paris, and Winkelmann, in Jena, have independently 
found what they believe to be evidence of refraftion through an 
aluminium prism. Both observers detedted a slight deviation, but 
in a diredtion toward the refradling angle, showing aluminium to 
have for these rays a refradtive index, slightly less with respedt to 
air than unity. 

i " Beohachliingen iiber das geschichtete eledtrische Licht, sowie 
iiber den merkwiirdigen Einfluss des Magneten auf dasselbe;" von 
Dr. W. H. Theodor Meyer. Berlio, 1838. 



that highest stage of exhaustion which one is prone to 
think of modern origin. 

In order to illustrate the successive phenomena which 
are produced when eledtric discharges are sent through a 
tube during progressively increasing exhaustion, there is 
here exhibited a set of identical tubes. Each is a simple 
straight tube, having sealed in at each end an eledtrode 
terminating in a short piece of aluminium wire. The 
eledtrode by which the eledtric current enters is known as 
the anode, that by which it leaves the tube as the kathode. 
The only difference between these eight tubes lies in the 
degree of rarefadlion of the interior air. The first one 
contains air at the ordinary pressure. As its eledtrodes 
are about 12 inches apart I am unable with the Apps 
indudtion coil (excited to throw an 8-inch spark) to send 
a spark through it. From the second tube about four- 
fifths of the air has been abstradted, and here we obtain a 
forked brush-like spark between the eledtrodes. The 
third tube has been exhausted to about one-twentieth 
part, and shows as the discharge a single thin red linear 
spark like a flexible luminous thread. When, as in the 
fourth tube, the exhaustion is carried so far as to leave 
but one fortieth, the red line is found to have widened out 
into a luminous band which extends from pole to pole, 
while a violet mantle makes its appearance at each end 
and spreads over both of the eledtrodes. On carrying the 
exhaustion to the stage shown by the fifth tube, where 
only about i-5ooth of the original air is left behind, we 
note that the luminous column has broken up transversely 
into flickering striae, that the violet mantle round the 
kathode has become more distindt, and is separated by a 
dark interval from the luminous red column, while a 
second and very narrow dark space appears to separate 
the violet mantle from the surface of the kathode. In the 
sixth tube the exhaustion has been carried to about 
i-io,oooth. The flickering striae have changed shape and 
colour, being paler. The light at the anode has dwindled 
to a small bright patch. The violet glow surrounding the 
kathode has expanded to fill the whole of that end of the 
tube ; the dark space has become more distindt, and 
within it the kathode now shows on its surface an inner 
mantle of dull red light. There is a slight tendency for 
the glass to show a greenish fluorescence near the kathode 
end. In the seventh tube the luminous column has sub- 
sided into a few greyish white nebulous patches, the dark 
space round the kathode has greatly expanded, and 
the glass of the tube has now begun to show a yellow- 
green fluorescence. The exhaustion has been pushed so 
that only about i-5o,oooth or less of the original air is 
present. In the eighth and last tube only one or two 
millionths of the original air have been left, with the 
result that the tube now offers an enormously increased 
resistance to the passage of the discharge. All the in- 
ternal flickering nebulosities have vanished ; the tube 
looks as though there were no residual air within. But 
now the glass itself shines with a fine yellow'green 
fluorescence which is particularly bright in the region 
around the kathode. Were the exhaustion to be carried 
much further the spark from this indudtion coil would no 
longer pass, so high would the resistance become. All 
these successive stages up to the last can be shown in 
one and the same tube attached to a modern rapid air< 
pump. But for the proper production of the high vacua 
of the last stages, where eledtric shadows are alone pro- 
duced, nothing short of a mercurial pump, either in the 
form invented by Sprengel or in that used by Geissler 
(or one of the recent modifications) will suffice. 

The phenomenon of fluorescence of the glass, which 
manifests itself when the exhaustion has become suffi- 
ciently high, was known in a general way as far back as 
1869 or 1870. The tube next to be shown is a modern 
reprodudlion of a tube used at that time by Hittorf, of 
Miinster. It differs from the tubes last shown by having 
a bend in it. Hittorf observed that when such a tube is 
exhausted sufficiently highly to give at the kathode the 
characteristic greenish yellow fluorescence, this greenish 



I^BBIilCiL NBWt, 1 

Feb. 26, 1897. f 



Electric Shadows and Luminescence, 



105 



yellow fluorescence refused to go round the bend. It 
might appear at one end or the other, according to the 
direiftion in which the discharge was being sent, but 
would not go round the bend. The effedt was as if the 
discharge went in straight lines from the bit of wire 
that served as kathode to the walls of the tube. Indeed 
shadow effecas were observed by him, and by Wright, 
of Yale, and afterwards independently by Crookes, who 
greatly extended our knowledge of the fadls. We may 
take this fadt, that the fluorescence caused by the kathode 
will not go round a corner, as the starting-point of the 
memorable researches of Crookes on radiant matter a 
score of years ago. 

Before you are several tubes which illustrate the re- 
searches made by Crookes. The first is a simple glass bulb 
into which are sealed the two ele^rodes, — the anode, by 
which the current enters, terminating in a bit of stout alumi- 
nium wire ; the other, by which the current leaves, called 
the kathode, terminating in a small flat aluminium disk. 
The glass bulb was itself highly exhausted — how highly 
we shall presently see. From the flat front surface of the 
kathode, when sparks are sent through the bulb, a sort 
of back-discharge takes place in a diredtion normal to 
the surface. This discharge, which only occurs at a very 
high degree of exhaustion, possesses several properties 
which distinguish it from all other kinds of discharge. It 
is propagated in straight lines, causes a brilliant lumines- 
cence wherever it strikes against the glass walls of the 
tubes, casting shadows of intervening objeds, it heats the 
surface on which it impinges, and strikes them with a 
distindt mechanical force. Singular to relate, it is also 
capable of being defledled by a magnet as though it were 
a flexible condudtor carrying the current. Struck by the 
singularity of these kathode rays or kathode discharges, 
which formed the subjedt of several beautiful researches, 



fadtion, the diredtion of these kathode rays was found to 
be independent of the position of the anode. He found 
kathode rays to be produced even when no internal 
ele&rodes were inserted, and when, instead, external 
patches of tinfoil were attached to the glass. Their me- 
chanical adtion he studied by causing them to impinge 
upon the vanes of a pivoted fly, which was thereby set 
into rotation. In a later experiment he caused the fly of 
a *' molecule mill " to be set into rotation, not by the im- 
padt of the kathodic discharge, but by the kinetic energy 
of the particles returning back toward the anode after 
they had impinged against the walls of the tube and lost 
their negative eledtric charges. A mere resume of 
Crookes's work in those years beginning about i86g or 
1870, and extending not only for ten years adtively, but 
going on at intervals until a year or two ago, would of 
itself fill a whole course of ledtures. Into the controversy 
which has arisen between Crookes and the English 
physicists on the one hand, and the German physicists on 
the other, there is no need to enter. SufSce it to say 
that while the German physicists mostly rejedl Crookes's 
hypothesis of radiant matter, and regard all these various 
phenomena as the result of mere wave-motions within 
the tube, the British physicists, including Lord Kelvin 
and Sir George Stokes, accept Crookes's view of the 
material nature of the kathode rays. Who, indeed, that 
has seen the molecule mill at work can doubt that, 
whether vibrations are present or not (and doubtless there 
are vibrations present), there are adtually streams of 
moving particles as an essential feature of the kathodic 
discharge ? For the moment the vidtory undoubtedly 
rests with the views of Crookes. 

But of all these phenomena the one which concerns us 
most is that of the produdtion of eledtrical shadows. 
Eredting in the path of the kathode rays an obstacle cut 





Fig. I. 



Crookes advanced the hypothesis that they consisted of 
flights of negatively eledlrified particles or *' radiant 
matter." The particles he sometimes spoke of as mole- 
cules, sometimes as dissociated atoms, or, as we should 
now say, ions. He studied the wanderings of these flying 
particles by inserting within the bulb at different points 
auxiliary eledtrodes. He found the interior of the bulb to 
be positively eledlrified in all parts except within the dark 
space which surrounds the kathode, that is to say, except 
within the range of the adlual kathode discharge. The 
kathode discharge itself was found to be possessed, to an 
extent exceeding any other known agency, of the power of 
exciting fluorescence and phosphorescence in minerals and 
gems. The kathode rays were themselves discernible as 
they crossed the interior of the tube. In such a bulb the 
kathode rays would form a blue streak impinging straight 
upon the anode. The kathode used in the next Crookes 
tube is of a concave shape. Crookes found that, since 
the kathode rays left the surface normally, the result of 
curving the kathode was to focus the rays toward the 
centre of curvature. By so focussing the rays upon a bit 
of platinum foil, it was found possible to fuse and even 
melt the metal. 
Unlike the discharges obtained at lower stages of rare- 



Fia. 2. 



out in sheet metal, — a cross of thin aluminium is the 
favourite objedt, — a shadow of it is observed to be cast 
upon the wall of the tube behind it ; the glass phosphor- 
escing brilliantly except where shielded from the impadl 
of the kathode rays, so that the shadow comes out dark 
against a luminous background. Common soda-glass 
gives this greenish golden tint, while lead-glass exhibits 
a blue phosphorescence. Not glass alone, but diamonds, 
rubies, emeralds, calc-spar, and other earthy materials, 
such as alumina, and notably yttria, produce the most 
brilliant efledts under the kathode discharge, some of them 
only fluorescing transiently, others with a persistent 
phosphorescence. As a sample is shown a tube in which 
a sea-shell, slightly calcined to remove organic matter, is 
made to emit a brilliant luminescence under the impadt of 
rays from a kathode placed above it. The shell itself 
casts a shadow against the lower part of the tube. Some 
of the shadow effedls are very mysterious, and have 
recently claimed much of my attention. The size of the 
kathodic shadows is affedled by the eledtrical state of the 
objedl. Eledtrifying it positively makes its shadow shrink 
to smaller dimensions. Eledtrifying it negatively causes 
a singular enlargement of the shadow. There seems to 
be no difference between the shadow of a metallic body 



io6 



Animal and Vegetable Fats and Otis. 



/ C^bhiCal NbW», 
• Feb. 26, 1897. 



^nd that of a non-metallic body of the same size. All 
bodies cast shadows, however thin. Even a film of glass 
I- 10,000th of an Inch thick — so thin that it showed 
iridescence like a soap-bubble — was found by Crookes to 
cast its shadow. 

Another point noticed by Crookes was that if the ex- 
haustion is carried very far, and the tube is stimulated by 
a sufficiently strong electromotive force, the phosphores- 
cence may occur at points not in the line of discharge, 
but round a corner. Not that the kathode rays turn the 
corner, however. Apparently some of the more quickly 
moving, or perhaps more highly charged particles, — atoms, 
molecules, or ions, those, in fadt, described by Crookes 
as " loose and erratic," — would manage to get round the 
corners and produce effe(Ss of a more or less diredtly 
kathodic kind in places where they could not have pene- 
trated by any motion in a straight line. 

Here (Fig. i) is a tube — a variation on one of Hittorf's. 
having two branches that cross one another at right 
angles. There are two small disks of aluminium in the 
bulbous ends to serve as eledrodes. When either of these 
is made the kathode, the whole limb in which it is situated 
fluoresces brilliantly of a golden-green tint, particularly 
at the distant end. But the other limb remains dark, save 
for a little nebulous blue patch, near the anode, due to 
residual gas. Another tube (Fig. a) is made as a zigzag, 
and here again only the end branch shines. On reversing 
the current the luminescence shifts to the other end. 
But when the tube is more highly exhausted, the phos- 
phorescence is observed not only in the end branch where 
the kathode is, but also slightly at the end wall of each 
branch of the zigzag. Apparently the residual gas will 
ai5t partly as its own kathode, and throw off something 
which causes the glass beyond to phosphoresce. 
(To be continued). 



NOTICES OF BOOKS. 



Chemistry for Engineers and Manufacturers. A Pra&ical 
Text-book. By Bertram Blount, F.I.C., F.C.S., 
Assoc. Inst. C.E., and A. G. Bloxam, F.I.C, F.C.S. 
With Illustrations. Vol. II., Chemistry of Manufac- 
turing Processes. London : Charles Griffin and Co. 
(Ltd.). 1896. 8vo., pp. 484. 
This volume is devoted to notices of the sulphuric acid 
manufadlure; of alkali and its by-produdts ; of destrudtive 
distillation, including the gas-manufadture ; of artificial 
manures, petroleum, lime, and cement ; of the clay in- 
dustries, and glass, sugar, and starch ; of brewing and 
distilling ; oils, resins, and varnishes, soaps and candles, 
textiles and bleaching colouring-matters, dyeing and 
printing ; of paper and pasteboard, pigments and paints, 
leather glue and size, explosives and matches ; and of the 
minor chemical manufa^ures. 

The reader will be surprised at finding all these arts 
and manufadlures— some of capital importance — treated 
in the compass of 437 pages ; but the authors explain in 
their Preface that they seek to expound those dominant 
principles which, they allege, " are too often hidden be- 
neath masses of mere detail, and are consequently apt 
to be overlooked by the specialist in any one branch, to 
his detriment, in that he frequently fails to apply to his 
own work principles which are matters of common know- 
ledge elsewhere." 

It is to be regretted that no instances are given of this 
overlooking which so frequently happens. According to 
our own observation the specialist eagerly, and even 
anxiously, looks about for principles which may throw 
light upon his own department. 

The bibliography seems to us somewhat deficient ; not 
a few important works on different departments have been 
overlooked. 



We regret to find that the authors have omitted the 
opportunity to deal a blow in passing at the recent stulti- 
fication of the Methylated Spirit Adt. If the Excise 
wished to render methylated spirit absolutely undrinkable, 
they might have demanded the addition to the spirit of a 
few drops of Dippel's animal oil, which is successfully 
used in Germany, and which does not interfere with 
industrial uses. 

The addition of dyes and mordants to sugar — an in- 
creasing evil — should be carefully looked into. 

Mention is made of a fraudulent custom in the pigment- 
trade, pale chrome-yellows being called and sold as pure 
when let down with lead sulphate. Hard waters for the 
use of the dyer and tissue-printer are rightly objeAed to ; 
if a hard water is required for any special process, it is 
better to add a salt of lime to a pure-water supply. 

The manufadture of artificial silk is considered as 
hitherto not a commercial success. 

In the matter of the vinegar manufadture, it may be 
asked why sugar at its present prices is not used in pre- 
ference to malt, save for domestic manufadture ? No 
mention is made here of date vinegar, which is coming 
into use. 

This work will be found useful to manufacturers who, 
without being chemical specialists, wish to have a general 
insight into chemical manufactures. 



A Practical Treatise on Animal and Vegetable Fats and 
Oils, both Fixed and Volatile ; their Physical and 
Chemical Properties and Uses, the Manner of Extradting 
and Refining them, and Pradtical Rules for Testing 
them — as the Manufadture of Artificial Butter, of 
Lubricants, &c. With Lists of American Patents 
relating to the Extradtion, Rendering, Refining, Decom- 
posing, and Bleaching of Fats and Oils. By William 
T. Brannt, Editor of the " Techno-chemical Receipt- 
Book," " Petroleum," &c. Second Edition, Revised 
and in great part Re-written. Illustrated with 302 
Engravings. In Two Volumes. Vol. I., pp. 528; 
Vol. II., pp. 728. Philadelphia : H. C. Baird and Co. 
London : Sampson Low, Marston, and Co. (Ltd.). 
1896. 
Wb have here an encyclopaedia of the animal and vege- 
table fats and oils from a botanical, chemical, industrial, 
and commercial point of view. The analysis of oils, 
whether for identification or for the detedtion of frauds, 
presents great difficulties. Numerous processes, physical 
and chemical, have been applied, not without success. 
But the properties of oils are apt to be modified by age, 
by climate, by the soils of their native countries, so that, 
especially in forensic cases, it becomes very difficult for 
the expert to give an apodidtic decision as to the genuine 
or fraudulent character of any sample in question. We 
have here a most elaborate table of the colour readtion, 
with a mixture of sulphuric and nitric acids, with potash 
and soda lye, with zinc chloride, with hydrochloric acid 
and sugar. Next come the well-known elaidin test, the 
thermal test of Maumen^, and Fehling test, depending on 
the heat liberated on mixing fatty oils with sulphuric acid 
at density 1*840; Tomlinson's cohesion figures, which 
require the outlay of much time before trustworthy results 
can be reached. 

Among quantitative methods there rank the determina- 
tion of the ester number, of the acid number, the acid 
number + the ester number being the Kottstorfer saponi- 
fication number; the determination of the fatty acids 
insoluble in water (Hehner's number) ; determination of 
the volatile fatty acids (Reichert's number) ; the iodine 
absorption (Hiibl's number). The determination of oxy- 
fatty acids gives the acetyl number of Benedikt-Ulzer. 

In determining the purity of an oil, the author 
examines firstly the argonoleptic and generally the phy- 
sical properties. He then applies the qualitative chemical 
methods, and, lastly, the quantitative procedures. 



Cbkuical Niwb, I 
Feb. 36, 1897. I 



Chemical Notices Jrom Foreign Sources, 



107 



among which Hiibl's iodine number is most generally 
determined. 

A table shows the approximate relative commercial 
value, and hence gives a key to the oils likely to be used 
for fraudulent purposes. 

No small trouble is occasioned in commerce by the 
circumstance that the seeds of the three species of 
Brasiica, which yield respedlively colra, rape, and rubsen 
oils, cannot be decisively distinguished from each other, 
either by measurement or by the aid of the microscope. 

The presence of any oil of this group — the products of 
the Cruet f era— m&y be detedled by boiling the oil with 
white-lead plaster {Emplastrum plutnbi). The oil is turned 
brown or black by the formation of lead sulphide. 

Sesame oil or gingelly oil is used as a table oil, and is 
esteemed fully equal to the best olive oils. It is a curious 
(si£t that, though the seed is chiefly grown in India, yet 
the oils pressed in Europe are considered superior to those 
pressed at home. 

Olive oil, in consequence of its high price, is especially 
open to fraud. Its eledtric condu^ivity is much lower 
than that of any other vegetable oil. Accordingly 
Palmieri has devised an apparatus — the diaxometer — 
which utilises this peculiarity. This instrument, how- 
ever, is expensive, and not easy of manipulation. More- 
over, leaving sophistication out of the question, olive oils 
are subject to spontaneous alterations which render the 
test untrustworthy. 

The spedtroscopic examination of olive oil is likewise 
not trustworthy. The absorption bands observed in olive 
oil are not due to the oil itself, but to chlorophyll, and do 
not occur at all in bleached oils. 

M. Brull6, Diredtor of the Agricultural Station at Nice, 
has devised two methods of testing the purity of olive 
oils, showing the kind and quantity of other oils used for 
their sophistication. 

These two tests we shall give in extenso on a future 
occasion. We must remember that dishonest merchants 
and manufafturers now consult experts who are them- 
selves unscrupulous, or who are carefully kept in ignorance 
of the purposes for which their advice is required. 

We shall return to this most valuable work at the 
earliest opportunity. 



CORRESPONDENCE. 

HOW SOON SHALL THE STUDENT BEGIN 
THE STUDY OF QUALITATIVE ANALYSIS ? 

To the Editor of the Chemical News. 
Sir,— Mr. Beebe's article in your last issue is an interest- 
ing one, and will I hope bring some comment. I should 
think, however, that few teachers would agree with him, 
for surely qualitative analysis is an application of the 
science and not the science itself. The great diiSculty 
is to induce pupils to think, and though one may be care- 
ful to point out that qualitative analysis is really a 
chemical Euclid, I have found but few pupils who will 
work through their analyses according to the syllogistic 
method of the great geometer. The attention given to 
schemes of analysis, and the importance given to the 
testing of powders until recently by the Science and Art 
Department have done much to take away the educational 
value of chemistry as a school subject. 

As regards danger in making the common gases, these 
will have to be made some time, and if it is pointed out 
to a pupil why there is danger, and how to guard against 
it, no mishap is likely to occur, even should that 
" dangerous gas " hydrogen be the subjedt of the lesson. 
— I am, &c., 

.... C. J. Woodward. 

Municipal Technical Schools, 

Birmingham, Feb. aoth, 1897. 



CHEMICAL 



NOTICES FROM 
SOURCES. 



FOREIGN 



NoTB. — All degrees of temperature are Centigrade unlets otherwise 

expressed. 

Comptes Rendus Hebdomadaires des Seances, deV Academic 
des Sciences. Vol. cxxiv., No. 4, January 25, 1897. 

A medal was presented to M. Faye on the occasion of 
the 50th anniversary of his nomination as a Member of 
the Academy of Sciences. M. Faye made a suitable 
reply. 

Fluorescence of Vitrified Matters under the A(5tion 
of Rontgen's Rays. — M. jBagiquet. — The following 
phenomena have, I believe, not been hitherto signalised. 
The substances mentioned below become luminous under 
the influence of the X rays, in the following decreasing 
order: — Baked enamels ; crown glass ; flint-glass ; ordinary 
glass, and especially the kind known as crystal ; sheet-glass 
from the works of Saint-Gobain ; porcelain enamelled 
faience; enamel powder before baking; and even cut 
diamond. We know, also, that most of these substances 
are fluorescent in the violet and the ultra-violet rays. It 
is therefore possible to form with these substances 
fluorescent screens which enable us to repeat radioscopic 
experiments with this advantage, that the vitrified sub- 
stances just mentioned may be worked optically. The 
images obtained are more definite, though less brilliant, 
than are those with crystals cemented upon card hitherto 
employed. We utilise also successfully these substances 
for shortening the exposure in radiographic experiments, 
and we have not to fear the granular spots produced by 
the crystals above mentioned. Does this fluorescence of 
glass not explain the disputed fadl that persons affeded 
with cataradt see the X rays ? In fadt, if we place our- 
selves in the field of emission of a Crookestube, furnished 
with thick spedlacles with convex glasses, we experience 
the sensation of a light like that of phosphorus. This 
sensation is the result of the fluorescence of the glass, 
which forms before the eyes a luminous mist easily recog- 
nised by persons surrounding the patient. Besides the 
scientific applications there are an entire series of very 
beautiful experiments, which I am about classifying with 
a view to early publication. 

Adtion of Carbon Dioxide and Monoxide upon 
Aluminium. — MM. QuntJ! and Masson. — This paper 
will be inserted in full. 

Spedlra of the Non-metals in Fused Salts — 
Silicon. — A. de Gramont. — This paper will be inserted 
in full. 

On Chromium and Manganese Phosphides. — A. 
Granger. — Already inserted. 

Influence of Temperature on Rotatory Power. — 
Ph. A. Guye and Mile. E. Aston. — In all we know at least 
fifty adtive liquids whose rotatory power decreases with 
the elevation of temperature in the entire interval of the 
experiments. 

On Two Isomeric Trietbylene-dipbenyl Hydra- 
zines, a and /3. — In presence of hyposulphites the adlion 
of aldehyd or phenylhydrazine yields the isomer a 
almost pure. In neutral solutions aldehyd adting upon 
phenylhydrazine phosphate produces chiefly the 
isomer ^. 

On a High Homologue of Urea. — Oechsner de 
Koninck. — It seems very admissible that in proportion as 
the oxidising power of the system is weakened, the 
number of the atoms of carbon of the quaternary com- 
pounds eliminated by the kidneys increases progressively. 



Contribution to the Study of the Adtion of Zinc 
upon Red Wines. — L. A. Lovat. — Zinc denaturates red 
wines and renders them poisonous. Hence the use of this 
metal should be severely forbidden in the cock for casks, 
vats, &c. — Comptes Rendus, cxxiv., No. 5. 



108 



Meetings for the Week, 



rCHBUICAt NBWS, 

I Feb. a6, X897. 



NOTES AND QUERIES. 

%♦ Our Notes and Queries column was opened for the purpose of 
giving and obtaining information likely to be of use to our readers 
generally. We cannot undertake to let this column be the means 
of transmitting merely private information, or such trade notices 
as should legitimately come in the advertisement columns. 

Waterproofing Canvas. — I should like to know a good receipt 
for chemically rendering canvas, &c., waterproof, ours being a very 
old and almost obsolete method.— Weekly Reader, 



MEETINGS FOR THE WEEK. 



Monday, March ist.— Society of Arts, 8. (Cantor Leftures). "In- 
dustrial Uses of Cellulose," by C. F. Cross, 
F.C.S. 

Society of Chemical Industry, 8. " Relation 

of Colour to Quality in Malt," by J. W. Lovi- 
bond. " Hehner's Bromine Tests for Oils," 
by J. H.B. Jenkins. "Analysis of Super- 
phosphates," by J. H. Coste. 
Tuesday, 2nd.— Royal Institution, 3. "Animal Eleftricity," by 
Prof. A. D. Waller, F.R.S. 

Society of Arts, 8. " Gesso," by Matthew Webb. 

Wednesday, 3rd.— Society of Arts, 8. " English Orchards," by Geo. 

Gordon. 

Society of Public Analysts, 8. " The Composi- 

tion of Milk and Milk Produfts," by H. Droop 
Richmond. "Estimation of Milk Sugar in 
Milk "and "Detection of Mixtures of Diluted 
Condensed or Sterilised Milk with Fresh 
Milk," by H. Droop Richmond and L. K. 
Boseley. " Constitution of Milk," by H. Droop 
Richmond. " Copper in Peas," by R. Bodmer 
and C. G. Moor, M.A. " Coffee Palace Coffee 
Infusions," by E. G. Clayton. 
Thursday, 4th.— Royal Institution, 3. " Greek History and Extant 

Monuments," by Prof. Percy Gardner, F.S.A. 
— - Society of Arts, 8. ■ " The Mechanical ProduAion 

of Cold," by Prof. James A. Ewing, M.A., F.R.S. 

- Chemical, 8. Ballot for Election of Fellows. "Some 

Hydrocarbons from American Petroleum — I. 
Normal and Iso-Pentane," by Sydney Young, 
F.R.S., and G. L. Thomas, B.Sc. " The Vapour 
Pressures, Specific Volumes, and Critical Con- 
stants of Normal Pentane, with a Note on the 
Critical Point," by Sydney Young, F.R.S. "On 
the Freezing-point Curves of Alloys containing 
Zinc," by C. T. Heycock, F.R.S., and F. H. 
Neville. " The Oxides of Cobalt and the Co- 
baltites," by A. H. McConnell and E. S. Hanes. 

Friday, 5th.— Royal Institution, 9. " Some Curiosities of Vision," 
by Shelford Bidwell, F.R.S. 

Saturday, 6th.— Royal Institution, 3. " Eleftricity and Electrical 
Vibrations," by Right Hon. Lord Rayleigb, M.A., 
F.R.S. 



CHEAP SETS OF STANDARD BOOKS. 

In good condition, and sent Carriage Free in Great Britain. 
Philosophical Magazine, from commencement, 1798 to 1885 

(exc. I vol. and 7 >os.), 185 vols, half calf, <Stc., very scarce, £64, 
Watts' Di(5ty. of Chemistry and the Allied Sciences; complete set. 

UNABRIDGED EDITION, 9 VOls. cloth, 1872-81, £15, tor £8 8S. 

Do , New Ed , 3 vols. New, 1888-92 (Special o^er), £6 14s., for £4 15s. 
Thorpe's Dicity. of Applied Chemistry (complete set). 1895. The 

companion work to " Watts." 3 vols., New, £7 7s. for £5 128. 
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Proceedings of the Royal Society of London, Complete Set, 

from 1854 to 1889; 39 vols., 8vo. cloth. Scarce. £10 los. 
Philosophical Trans. Roy. Soc. Lond. Consecutive set, from 

1843 to 1889, 205 vols, or pts., cloth, &c., £50 (pub. ;^i89 9s. 6d.). 
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Chemistry applied to Arts and Manufa(5tures by writers of eminence 

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CHBUICAL N BW8, 

March 5, 1807. I 



Determination of Sulphur in Irons, 



109 



THE CHEMICAL NEWS. 



Vol. LXXV., No. 1945. 



THE AGE OF COPPER IN CHALDEA. 
By M. BERTHELOT. 



The discoveries made some years ago by M. de Sarzee, 
at Tello in Chaldea, have brought to our knowledge monu- 
ments of a high antiquity, extending back to the origin 
of civilisation, 5000 or 6000 years ago. They have fur- 
nished weapons, ornaments, and tools which throw a new 
light on the origin of the industry of metals. Such are 
the objedts deposited at the Louvre, which our colleague, 
M. Heuzey, has kindly referred to my examination. We 
find here the first and most ancient monuments belonging 
to the age of copper. . 

I. I have analysed a colossal lance or blade showing 
various designs and inscriptions, with the name of a king 
of Kish which goes back to an epoch anterior to Our- 
Nina, i. e., about 4000 years before our era. This lance 
has not been devoted to pradical service, but has a 
hieratic charader, having been consecrated to some deity. 
It is formed of a red metal, being strongly attacked in 
some parts and changed into a greenish paste. 

The filings of the metal consist of copper approximately 
pure, and I have found in it no tin, zinc, arsenic, or anti- 
mony in any appreciable amount. 

The oxidised portion consists of hydrated copper oxy- 
chloride (atacamite) free from carbonate. There was 
found in it neither arsenic, antimony, tin, or zinc, but a 
trace of lead. This substance, after drying in the stove, 
contained CI = ig'S, 

This oxychloride results from the adion of the brackish 
waters of the soil in the midst of which the blade has 
been lying for so many centuries. When once the objed 
is brought in contadl with the air, tlie presence of the 
alkaline chlorides and atacamite threaten a total dis- 
aggregation in consequence of its progressive conversion 
into super-copper oxide. This aggregation results from 
a certain series of readtions, set up by a small quantity of 
sodium chloride with the intermediation of atacamite, 
which I have defined by diredt experiment (Annales de 
Chimie et Physique, Series 7, vol. iv., p. 552). Most of 
the statues of copper found in the same excavations are 
undergoing this same decomposition at the Museum. 
They are wrongly labelled " Objects of Bronze," as they 
consist of pure copper. 

2. Hatchet with a socket formed of red metal. Broken 
fragments coated with a greenish patina. A similar in- 
strument is represented in the hands of Chaldean 
personages on the monuments from the epoch of Our- 
Nina to that of Goudea, that is, from the year 4000 to 
the year 3000 before our era. 

The fragments which I have analysed consist essentially 
of metallic copper associated with a little cupric oxide. 
No tin, lead, zinc, arsenic, or antimony. The hatchet 
has therefore not been formed of bronze, but of copper 
sensibly pure. 

3. Entire hatchet, red, with a sharp edge, horizontal 
and socketed. It has been found with its handle below 
the ancient construdlion of the king Our-Nina. M. 
Heuzey regards it as perhaps the most ancient relic met 
with in these excavations. The metal is hard, of pure 
copper, free from tin, lead, or zinc, but contains traces of 
arsenic and phosphorus. It seems to have been hardened 
by the concourse of these latter elements. But we do 
not possess the ores which have served in the manufadture 
of the Chaldean objedts, and we cannot assert, as is the 
case of the specimens from Sinai, that the presence of 
arsenic is due to the addition of some substance foreign 



to the copper ore properly so called. In any case I must 
here repeat that we have to do with copper, and not 
bronze, as the Chaldean tools, &c., contain no tin. 

4. Egg-shaped article, of a metallic aspedt, weighing 
121 grms., found along with the Chaldean remains. The 
filings consisted of iron partially oxidised, without arsenic, 
zinc, or alumina. 

5. Ingot and filings (ancient) of a white metal, 
found with the Chaldean remains in an urn of coarse 
pottery. The filings of the ingot contain : — Silver, gyi\ 
copper, a small quantity ; notable patina ; no lead. 

6. Leaf of yellow gold, of Chaldean or Assyrian 
origin. This gold contains neither copper, lead, nor iron 
in sensible proportion. It contains a considerable quan- 
tity of silver, which the minimal weight of the sample at 
my disposal did not permit me to determine with pre- 
cision. In this and other cases it is always the antique 
alloy of gold and silver known under the name of asem. 
The manner of purifying native gold was not well under- 
stood in Egypt and Chaldea in, those remote ages. 

The existence of successive degrees in the use of the 
purification of the metals, both common and precious, 
appears from these analyses. In particular, the use of 
pure copper for arms and tools was common in Chaldea 
about the year 4000 B.C. It preceded the use of bronze, 
t. e., copper alloyed with tin, which is found in later 
articles both in Egypt and Chaldea. We may even add 
that the form of hatchets with handles, the processes of 
moulding and manufadture, and even the practical uses to 
which the tools were destined, have been the same both 
for the pure hatchets of copper in Chaldea and for the 
prehistoric hatchets of Europe and Siberia. — Comptes 



Rendus, cxxiv., p. 328. 



CARBIDE OF CALCIUM. 

In consequence of the growing importance of carbide of 
calcium, and the fadt that the mere contadt of moisture 
with this material causes a dangerous evolution of the 
highly inflammable gas known as Acetylene, the Home 
Secretary has caused inquiries to be made into the sub- 
jedt, with the result that an Order in Council has to-day 
been made under the 14th Sedtion of the " Petroleum 
Adt, 1871," bringing carbide of calcium within the opera- 
tion of that Adt. 

Accordingly, from the date on which such Order comes 
into force, viz., ist April, 1897, >^ ^''' ^^ unlawful to keep 
carbide of calcium except in virtue of a license to 
obtained from the Local Authority under the 
Adt." 

Any Local Authority to whom application maybe made 
for a license to keep carbide of calcium can, if it so de- 
sires, obtain, on application to the Home Office, a 
Memorandum showing the charadler of the risks to be 
guarded against, and containing suggestions as to the 
nature of the precautions likely to be most effedtual for 
securing safety. 
Whitehall, 26th February, 1897. 



be 
Petroleum 



DETERMINATION OF SULPHUR IN IRONS. 
By OTTO HERTINQ. 

In the laboratories of many iron works it is customary to . 
be content with Wiborgh's method (colorimetric), as the 
determination by the bromine method is tedious, and very 
unpleasant where the ventilation arrangements are impar- 
fed. I will by no means deny the value of the colori- 
metric method, but wish to point out that the results are 
frequently very inaccurate, owing to imperfedtly con- 
struded apparatus or to escapes at the joints. The latter 



no 



Report of Committee on A tomic Weights. 



i CHKItlCAL NbW 

I March s, 1897. 



we may best deted by means of nitro-prusside papers. 
A disadvantage in Wiborgh's method which cannot be 
overlooked is, that we are compelled to use a very small 
quantity of material (0*2 to at most o*8 grm.) of borings, 
which is far too small a quantity. The most expeditious 
quantitative method which yields perfedlly satisfadory 
results, is, in my opinion, the following, which E. F. 
Wood (of the Homestead Steel Works) publishes briefly 
in Blair's "Analysis of Iron" p. 71 : — 5 or 10 grms. of 
borings are treated with hydrochloric acid ; the hydrogen 
sulphide evolved is condudled into an ammoniacal cad- 
mium salt (acetate or chloride) ; the cadmium sulphide is 
colleAed on a small filter, shaken out with cold water in 
an Erlenmeyer flask, mixed with «/20 solution of iodine 
in excess, which is then titrated back with a corresponding 
solution of thiosulphate. The entire operation can be 
completed in one hour. 

About two years ago Prof, de Koninck proposed to de- 
termine sulphur in irons, adding a small quantity of 
stannous chloride to the hydrochloric solution to prevent 
the formation of ferric chloride. I am now of De 
Koninck's opinion, that the oxygen of the air in i litre 
does not readl so quickly upon hydrogen sulphide as to 
occasion a separation of sulphur which might thus escape 
determination. Hence it is not necessary to expel the air 
of the flask by the introdudlion of a current of hydrogen 
or carbon dioxide.— CAemJ^^r Zeitung, Feb. 6. 



THIRD ANNUAL REPORT OF COMMITTEE 

ON ATOMIC WEIGHTS. 

RESULTS PUBLISHED DURING 1895.* 

By F. W. CLARKE. 

(Concluded from p. loi). 

Helium and Argon. — The true atomic weights of these 
remarkable gases are still in doubt, and so far can only 
be inferred from their speciflc gravities. For argon, the 
discoverers, Rayleigh and Ramsay (P/»7. Trans., clxxxvu, 
220 — 223) give various determinations of density, ranging 
H = i) from 19*48 to 20-6. The value I9'9 they regard 
as approximately corredt. 

For helium, Ramsay {yourn. Chem. Soc, iii., 684) gives 
the density 218, while Langlet {Ztschr. Anorg. Chem., 
x., 289) finds the somewhat lower value 2 00. 

From one set of physical data both gases appear to be 
monatomic, but from other considerations they are sup- 
posably diatomic. Upon this question, controversy has 
been most adtive, and no final settlement has yet been 
reached. If diatomic, argon and helium have approxi- 
mately the atomic weights 2 and 20 respedively ; if mon- 
atomic, these values must be doubled. In either case 
helium is an element lying between hydrogen and 
lithium ; but argon is most difficult to classify. With 
the atomic weight 20, argon fills in the eighth column of 
the periodic system, between fluorine and sodium ; but if 
it is 40, the position of the gas is anomalous. A slightly 
lower value would place it between chlorine and potas- 
sium, and again in the eighth column of Mendeleeff's 
table, but for the number 40 no opening can be found. 

It must be noted that neither gas, so far, has been 
proved to be absolutely homogeneous ; and it is quite 
possible that both may contain admixtures of other things. 
This consideration has been repeatedly urged by various 
writers. If argon is monatomic, a small impurity of 
greater density, say of a unknown element falling between 
bromine and rubidium, would account for the abnormality 
of its atomic weight, and tend towards the reduction of 
the latter. If the element is diatomic, its classification is 
easy enough on the basis of existing data. Its resemblance 



♦ Read at the Cleveland Meeting, December 31, 1895. 
Journal of the American Chemical Society, xviii., No. 3. 



From the 



H = 1. 

Aluminum 26*91 

Antimony 119*52 

Argon ? 

Arsenic 74"52 

Barium 136-40 

Bismuth 206*54 

Boron 10*86 

Bromine 79"34 

Cadmium iii'oS 

Caesium 131*89 

Calcium 3978 

Carbon 11*92 

Cerium .. .. .. 1391 

Chlorine 35° 18 

Chromium 5i'74 

Cobalt 58*49 

Columbium .. .. 93*3 

Copper 63*12 

Erbium 165*0 

Fluorine 1889 

Gadolinium .. .. 154*9 

Gallium 68*5 

Germanium .. .. 71*75 

Glucinum 901 

Gold 19574 

Helium ? 

Hydrogen 1*00 

Indium 112*8 

Iodine 125*89 

Iridium 191-66 

Iron 55'6o 

Lanthanum .. .. 137*6 

Lead 205*36 

Lithium 697 

Magnesium .. .. 24-11 

Manganese .. .. 54*57 

Mercury 198*5 

Molybdenum ., .. 9526 

Neodymium .. .. 139*4 

Nickel 58*24 

Nitrogen i3*94 

Osmium 189*55 

Oxygen 15879 

Palladium 105*56 

Phosphorus . . . . 30 79 

Platinum i93'4i 

Potassium 38*82 

Praseodymium.. .. i42'4 

Rhodium 10223 

Rubidium 84*78 

Ruthenium .. .. 100*91 

Samarium 148*9 

Scandium 437 

Selenium 78*4 

Silicon 28*18 

Silver 107*11 

Sodium 2288 

Strontium 8695 

Sulphur 3183 

Tantalum i8i*2 

Tellurium 126*1? 

Terbium 1588 

Thallium 20260 

Thorium 230*87 

Thulium 169-4 

Tin 118-15 

Titanium 47 79 

Tungsten 183*44 

Uranium 237*77 

Vanadium .. .. 50*99 

Ytterbium 171*7 

Yttrium 88*28 

Zinc 64*91 

Zirconium 89*9 



O = 16. 

27*11 

i2o*43 

? 

75 09 
13743 
20811 

10*95 

7995 

111-93 

132 89 

40*08 

12*01 

140*2 

35*45 

52 14 

58-93 

94-0 

63-60 

166-3 

1903 

156*1 

69*0 

723 

908 
197-24 

? 

1008 

"37 
126*85 
193*12 
56*02 
1386 
206-92 

703 
24-29 

5499 

200*O 
95-98 

140*5 
5869 
1404 

190-99 
16*00 

10636 
31 02 

194*89 

39*" 
143-5 
103 01 

85-43 
IOI-68 
150*0 
44*0 
790 
28 40 
107*92 
23-05 
87-61 
32-07 
182*6 
1270 ? 
160*0 
204*15 
232*63 
170-7 
119*05 

48-15 
184-84 

239-59 

51*38 
173*0 

88*95 

65*41 

90 -6 



CHbhical I<bws, 
March 5, 1897. 1 



Electric Shadows and Luminescence* 



lit 



to nitrogen, as regards density, boiling-point, difficulty of 
liquefa&ion, &c., lead me personally to favour the lower 
figure for its atomic weight, and the same considerations 
may apply to helium also. Until further evidence is 
furnished, therefdre, I shall assume the values 2 and 20 
as approximately true for the atomic weight of helium 
and argon. 

Carbon. — Wanklyn (Chem. News, Ixxii., 164 ; see also 
Phil. Mag., August, 1895 » ^'so the reports of this com- 
mittee for 1893 and 1894), on the basis of his investiga- 
tions into the composition of hydrocarbons, reiterates his 
belief that the atomic weight of carbon is not 12 but 6. 
This question is one which falls rather outside the scope 
of this report and needs no further discussion here. If 
Wanklyn's contention is sustained, the value assigned to 
carbon in the table accompanying this paper should be 
divided by two. 

In the accompanying table of atomic weights, the values 
are given according to both standards, H=3i and = i6. 
Many of the figures are the results of new and complete 
re-calculation from all available data, made in the pre- 
paration of a new edition of my " Re-calculation of the 
Atomic Weights." 



ELECTRIC SHADOWS AND LUMINESCENCE.* 

By Prof. SILVANUS P. THOMPSON, D.Sc, F.R.8., M.R.I. 

(Continued from p, 106), 

And now let me remark that not one of all the tubes 
shown since the first one is capable of showing a shadow 
upon the fluorescent screen outside, or of taking a photo- 
graph through a sheet of aluminium. Even the brilliant tube 
which showed so excellently the shadow of the cross, fails 
to show any result after hours of vain waiting. It yields 
no rays that will penetrate aluminium. For experiments 
with Rontgen rays it is absolutely necessary that the 
process of exhaustion should be carried beyond the 
stage that suffices for the produdtion of kathode shadows ; 
it must be pushed to about that limit which Crookes him- 
self described as his unit for the degreee of vacuum, 
namely, one-millionth of an atmosphere. I do not say 
that with long exposures photographs cannot be taken 
when the degree of exhaustion is lower. Something de- 
pends, too, upon the degree to which the eledlric discharge 
is stimulated, and something also depends upon the shape 
and structure of the tube and upon the size and shape of 
the kathode. But on none of these things does the 
emission of X-rays depend so much as upon the degree 
of vacuum. The highly exhausted vacuum is the one real 
essential. 

So soon as Crookes's researches upon eledtric shadows 
had become known, eledtricians set to work to try to pro- 
duce eleiftric shadows in ordinary air without any vacuum. 
One of the ablest of experimenters. Prof. W. Holtz, was 
successful, using as a source of eledtric discharge the 
eledlrified wind which is given off by a metal point 
attached to the pole of an influence machine. If in a 
perfectly dark room such a point is placed opposite and at 
a few inches from a wooden disc covered with white silk 
and connected at its back or edges to the other pole of the 
machine, it will be observed to show a pale luminosity 
over a circular patch where it is struck by the eledtric 
wind. If then the objedl is brought between the disc and 
the point a shadow will be observed to be cast upon the 
white surface. Non-condudlors do not cast shadows as 
well as condudtors do. A piece of thin mica scarcely 
casts a shadow at all until it is moistened. Double 
shadows can be got by using two disks covered with silk 
facing one another ; any condudting objedt introduced 
between them casts a shadow on both. If such a shadow 



• A Ledture delivered at the Royal Institution of Great Britain. 
Friday, May 8, i8g6. 



from an eledlrified point is cast downward upon a sheet of 
ebonite or pitch, the parts not shaded are found after- 
wards to remain eledlrified, and can be discovered by 
scattering over them Lichtenberg's mixed powders of red- 
lead and lycopodium, thus perpetuating the shadow. 

But now it is possible to produce eledlric shadows in 
another way, photograpically, as has been known for 
some years {Proc. Phys. Soc. Land., xi., 353, 1892), from 
metal objedls such as coins, by simply laying them down 
upon a photographic dry-plate (a gelatino-bromide plate) 
and sending an eledlric spark (from an indudlion-coil) 
into them. 

Fig. 3 shows the arrangement adopted by the Rev. F. 
J. Smith, who is kind enough to exhibit in the library to- 
night some scores of his beautiful " indudloscript " photo- 
graphs. Upon the screen I throw a few samples, in- 
eluding a print of one of the Jubilee coins (Fig. 4). 
These curious photographs are produed simply by the 
chemical adlion of the eledlric discharges which stream 
off from all the projedling portions, and so roughly repro- 
duce an image of the coin. Since Rdntgen's discovery 
many persons have announced their supposed discovery 
of the produdlion of eledlric shadow-pidlures without the 
aid of a Crookes tube. What they have really observed 
is, however, totally different. They have not been pro- 
ducing X-rays at all, but have merely re-discovered these 
indudloscript shadows. 

Between the researches of Crookes, however, and those 
of Rontgen, there came in a very remarkable body of 
researches in Germany. I have but to name Goldstein, 
Puluj, Hertz, Wiedemann, and Lenard (See Note), 
amongst the workers, to show what interest has been 
concentrated on the subjedl. Hertz, whose loss Science 
has not ceased to lament, observed that a part at least of 
the kathode rays were capable of passing through thin 
aluminium sheet, a property which confirmed him in his 
previous doubt as to the material nature of the kathodic 
discharge. His pupil, Philipp Lenard, now Prof. Lenard, 
of Aachen, took up the point. He fitted up a tube with a 
small window of aluminium foil opposite the kathode, its 
form being that shown in Fig. 5. The kathode was a flat 
disk on the end of a glass covered wire stem. The anode 
was a cylindrical tube of brass surrounding the kathode. 
Upon the further end of the tube a brass cap was fixed 
by means of vacuum-tight cement. Over a small orifice 
in this brass cap was set the aluminium window of foil 
only i-4ooth m.m. thick. By this means he was able to 
do what had previously been supposed impossible — bring 
the kathode rays out into the open air. Or, at least, that 
is what he appears to have considered that he was doing. 
Certainly he succeeded in bringing out from the vacuum 
tube rays that, if not adlual prolongations of the kathode 
rays, were closely identified with them. He examined 
their properties both in the open air and in gases contained 
in a second chamber beyond the window, and found them 
to be capable of producing photographic impressions on 
sensitive plates. He further examined the question 
whether they can be defledled by a magnet. Fig. 6, which 
is copied from Lenard's paper, shows the results. The 
row of spots on the left side shows the photographic efifedl 
under various different conditions of experiment when there 
was no magnet present. The spots in the right-hand row 
show the effedls obtained when a magnet was present. 
For example, in the third row from the top it is seen that 
the bundle of rays when subjedled to the influence of the 
magnet is partially dispersed, the spot being enlarged 
sideways and having a kind of nebulous tail. This proves 
that through the aluminium window there came some 
rays which were defledled by a magnet, and some rays 
also which were not defledled by a magnet. The question 
naturally arises whether the rays which Lenard had thus 
succeeded in bringing out into the open air are the 
same thing as the rays with which Crookes had been 
working with inside the vacuum. To that question the 
final answer cannot yet be given. Certainly some of the 
Lenard rays resemble the interior kathode rays ; but some 



112 



Electric Shadows and Luminescence, 



( Chemical News, 
l March 5, 1897. 



differ in the crucial respea of defiedtability by the 
magnet. The higher the degree of vacuum, the less are 
the rays defledted. 

Note. 

Goldstein, in his " Researches on the Refledion of 
Eledtric (t. «., Kathode) Rays," in Wiedemann's Annalen 
(xv., 246, 1882), came very near to the discovery of the 
Rontgen rays. After pointing out that Hittorf had held 
the opinion that the kathode rays end at the place where 



Dry pZcUe 



FLate- of Copjur 




Fig. 3. 

they strike upon a solid wall, and that they are unable to 
proceed in any direction at all from thence, Goldstein 
dire(5ls attention to the circumstance that fluorescent 
patches are sometimes seen at the end of crooked tubes, 
where they could not have been caused by the dired 
impaft of kathode discharges. He discusses the question 
whether this is due to reflexion or to a defledlion caused 
by the spot where impadl first took place having become 
eleiftrified negatively, and therefore afting as a secondary 
kathode. The latter hypothesis is rendered untenable by 
his observation that if the spot of first impadt is made an. 
anode the efFed still occurs. He then shows that the 
phenomena are inconsistent with a specular refle(5tion, but 




Fig. 4. 

are explained by supposing that there is a diffuse reflec- 
tion. He then sums up as follows: — "A bundle of 
kathode rays does not end, at least under those circum- 
stances under which it excites phosphorescence, at the 
place where it strikes upon a solid wall, but from the place 
of impadt on the wall there proceed eledtric rays in every 
diredtion in the gaseous space. These rays may be con- 
sidered as refledled. Any solid wall of any property 
whatever may serve as a refledting surface. It is imma- 
terial whether or not it is capable of phosphorescence, or 
whether it consists of an insulator or of a condudior. 



The refledtion is diffuse, no matter whether the surface is 
dull or most highly polished. An anode refledts the 
kathode rays sensibly as well as a neutral condudtor or an 
insulator. The refledled rays have, like the diredl kathode 
rays, the property to excite phosphorescence at their 
ends. They are subjedl to defledlion, and their ends are 
deviated in the same sense as the ends of kathode rays, 
which would extend from the reflecting surface toward the 
place hit by the refledled rays." 

Puluj, " Radiant Eledlrode Matter, and the so-called 
Fourth State." Published in vol. i. of " Physical Me- 
moirs," by the Physical Society of London, 1889. These 
are translated from papers published in 1883 in the 
Memoirs of the Imperial Academy oj Sciences at Vienna. 




Fig. 5. 



H. Hertz. " Researches on the Glow - Discharge," 
Wied. Ann., xix,, 782, 1883. Hertz regards the kathode 
rays as a property of the ether, not as consisting of 
moving particles. He flnds the kathode rays to consist 
of a heterogeneous variety of kinds which differ from one 
another in their properties of causing phosphorescence, of 
being absorbed, and of being defledled by the magnet. 



2. 








iSr. 



Fig. 6. 



" On the Transmission of the Kathode Rays through 
Thin Layers of Metal" (xlv., 28, 1892), Hertz finds that 
glass fluoresces in kathode rays, even if covered with gold- 
leaf or thin films of various metals, though not if covered 
with thin mica. Aluminium was found best, and allowed 
fluorescence to occur even when a sheet of aluminium- 
leaf was used so thick as to be opaque to light. A 
diaphragm of thin aluminium-leaf on a metal frame 
placed inside a Crookes tube at 20 cm. from the kathode, 
permitted enough rays to pass to give a tolerably bright 
and even fluorescence over the whole of the further end 
of the tube. These rays, after passing through the leaf 



Crbmical NBW8, I 
March 5, 1897. I 



Oxalates of Zirconium, 



113 



of metal, still showed redilinear propagation (with some 
diiTusion), and had not lost the property of being defiedted 
by the magnet. 

E. Wiedemann's papers, which are of special im- 
portance, have mostly appeared in Wiedemann's Annalen. 
The following are the chief of them. Some of the later 
have been written in collaboration with Prof. H. Ebert. 

" On the Phosphorescent Light excited by Eledtric Dis- 
charges" {Wied. Ann., ix., 157, 1880). 

" On Eiedtric Discharges in Gases " (xx., 756, 1881). 

•' On Fluorescence and Phosphorescence," Pt. i (xxxiv., 
446, 1888). 

'• On the Mechanism of Luminosity " (xxxvii., 177, 
1889). 

" On Kathodo- and Photo-Luminescence of Glasses " 
(xxxviii., 488, 1889). 

" On Eledlric Discharges in Gases and Flames " (xxxv., 
209, 220, 234, 237, 255, 1888). 

"On Eledtric Discharges" (xxxvi., 643, 1889). 

" On the Apparent Repulsion of Parallel Kathode Rays " 
(xlvi., 158, 1892). 

" On Eledric Discharges ; Excitation of Eledtric Oscil- 
lations and the Relation of Discharge-tubes to the same " 
(xlviii., 549, and xlix., i, 1893). 

" Researches on Eledlrodynamic Screening-a(5tion and 
Eledtric Shadows" (xlix., 32, 1893). 

" Luminous Phenomena in Eledlrode-less Rarefied 
Spaces under the Influence of Rapidly-alternating Elec- 
tric Fields" (I., I, 221, 1893). 

With J. B. Messerschmitt, "On Fluorescence and 
Phosphorescence, Pt. II., Validity of Talbot's Law" 
(xxxiv., 463, 1888). 

With H, Ebert, "On the Transparency of Kathode 
Deposits," Sitzber. d, Phys.-Med. Soc. zu Erlangen, Dec. 
14, 1891. 

Lenard's Papers are: — 

" Note on a Phosphoroscope, with Spark Illumination " 
{Wied. Ann., xxxiv., 918, 1888). 

With M. Wolf, "Luminescence of Pyrogallic Acid" 
(xxxiv., 918, 1888). 

With V. Klatt, " On the Phosphorescence of Copper, 
Bismuth, and Manganese in the Sulphides of Alkaline 
Earths" (xxxviii., 90, i88g). 

" On Kathode Rays in Gases at Atmospheric Pressure, 
and in the most Extreme Vacuum " (li., 225, 1894). 

" On the Magnetic Deflexion of the Kathode Rays " (Hi., 
22, 1894). 

" On the Absorption of the Kathode Rays" (Ivi., 255, 
1895). 

(To be continued). 



THE OXALATES OF ZIRCONIUM. 
By F. P. VENABLE and CHARLES BASKERVILLE. 

The text-books of chemistry make either very little or no 
reference to the oxalates of zirconium. Beyond an occa- 
sional reference to the oxalate or basic oxalate gotten by 
precipitating with oxalic acid or an oxalate, we can find 
little mention of these compounds. Behrens, in his micro- 
chemical work, speaks of an oxalate prepared as colour- 
less pyramids by precipitating a solution of zirconium 
sulphate with potassium binoxalate, but no analyses are 
given, and the crystals could scarcely have been the pure 
oxalate. Paykull (" Ofv. af. Vet. Ak. Forhandl.," ref. in 
Ber. d. Chem, Ges., xii., 1719) speaks of double oxalates 
being prepared with the alkaline oxalates (i : 2) and his 
failure to prepare the neutral oxalate. His methods, and 
indeed full results, are unknown to us, as we did not have 
access to the original paper. 

We may summarise the work which follows in the suc- 
ceeding pages by saying that we found it possible to pre- 
pare the basic oxalates by precipitation. This was 



usually in the form of Zr(C204)2.Zr(OH)4, though other 
ratios were gotten. The neutral oxalate we did not suc- 
ceed in preparing, but instead the tendency seems to be 
toward the formation of the acid oxalate, — 

Zr(C204)2.H2C204'8H30. 
This tendency toward the formation of acid salts was 
shown also in the double oxalates. Two of these were 
prepared. For sodium, — 

Zr(C204)2.3NaC204.H3C204.5H20, 

and for potassium the salt — 

[Zr(C204)2]2.(K2C204)2.H2C204.8H20. 

The oxalate with ammonium as a constituent was not so 
easy of preparation in a pure state. The compound 
secured was Zr(C204)2.2(NH4)2C204. The experiments 
and analyses are given in detail. 

Zirconium Oxalates. 

The Oxalate Gotten by Precipitation.— On the addition 
of a saturated solution of oxalic acid to a slightly acid 
solution of zirconium chloride until no further precipita- 
tion occurred, a gelatinous precipitate formed which had 
very nearly the composition Zr(C204)2 2Zr(0H)4. Ana- 
lysis I. gave Zr 46-39, and C2O4 30-89, instead of the 
theoretical 4640 and 30-93 respedively. The filtrate 
from this was turbid, and on standing yielded another 
precipitate which had nearly the composition 
2Zr(C204)2.3Zr(0H)4. 

These basic oxalates are very difficultly soluble in 
acids, and of extremely fine subdivision, settling slowly 
and passing through even the best filters. It does not 
seem probable that they could be secured of very constant 
composition. Probably basic oxalates with many different 
ratios between the oxalate and the hydroxide might be 
secured. On drying at 100°, or even a little lower, the 
oxalic acid is gradually volatilised and lost. This is true 
of all the oxalates and double oxalates prepared, so that 
the only mode of drying these preparations was between 
filter-paper. 

The Acid Oxalate prepared by Crystallisation. — In pre- 
paring this oxalate, zirconium hydroxide was dissolved in 
oxalic acid. The hydroxide is quite soluble in oxalic acid, 
and a concentrated solution is readily obtained. A con- 
siderable excess of the acid is required to hold the oxalate 
thus formed in solution. If this solution be acidified by 
means of hydrochloric acid a very fine precipitate is ob- 
tained, settling very slowly, easily passing through the 
best filter-papers, and insoluble even in a considerable 
excess of the acid, but soluble in concentrated suljhuric 
acid. This precipitate was not analysed, nor were the 
exadt conditions of its formation determined, as its exam- 
ination did not promise results of sufficient importance 
to justify overcoming the difficulties in the way. 

On evaporating the acid solution of the oxalate the 
excess of oxalic acid first crystallises out. In the various 
preparations made, the first one or two crops of long 
crystals were found to be nearly pure oxalic acid, and 
were rejedted. Then the form of the crystals changed to 
small granular or prismatic masses, and with each suc- 
ceeding crop of crystals the percentage of zirconium in- 
creased, reaching speedily an approximately constant 
ratio. No difference in the form of the crystals in these 
different crops could be deteded on superficial examina- 
tion, and hence it was impossible to distinguish between 
the zirconium oxalate and the oxalic acid almost free of 
zirconium, except by analysis. In no case was the 
normal oxalate secured. The analyses showed a tendency 
toward the formation of an acid oxalate and to mixtures 
of this with the normal oxalate. These mixtures were 
gotten in the later crystallisations, but the last crystallisa- 
tion, when nearly the whole would solidify into a crystal- 
line mass, showed decreased percentages of zirconium. 
It is possible that larger amounts than we had at our dis- 
posal would enable one so to fra(aion the crystallisation 
as to secure a pure oxalate. It is, however, questionable 



114 



Oxalates of Zirconium. 



Chemical Nbws, 

March 5, 18Q7. 



whether the normal oxalate can exist in solution without 
admixture with some oxalic acid. 

Four series of crystallisations were made, and in two 
cases fairly abundant crops of crystals corresponding to 
the acid oxalate were obtained. In each series enough of 
the zirconium hydroxide was taken to form about 20 grms. 
of the oxalate. 

First series. Second series. 
Sixth fraflion. Fifth fraction. 

II. III. ^rCCjOtVHjCaO,. 

Zr .. .. 25*44 25*28 25'53 

Ca04 .. .. 74*55 7472 74*47 

These are calculated upon the water-free basis. The 
crystals contained 29*34 ^nd 29*27 per cent of water 
respeaively, where the salt Zr(C204j2H2C204.8H30 con- 
tains 28 90 per cent. Other crops of crystals contained 
percentages of zirconium not varying greatly from these 
given above as 28*14, 27-62, 24*9, 23*83. The percentage 
of zirconium in the normal oxalate is 33*96. 

Zirconium Sodium Oxalate. 

The addition of sodium oxalate to a slightly acid solution 
of zirconium chloride gives a gelatinous white precipitate. 
Most of this dissolves in an excess of the oxalate. The 
undissolved portion settles to the bottom, and after pro- 
longed standing a second layer of a more powdery appear- 
ance forms. This can also be gotten by concentration of 
the filtrate from the first precipitate. Analysis showed 
that the first gelatinous precipitate was chiefly Zr(0H)4. 
The second precipitate was a double oxalate of zirconium 
and sodium, but was either of inconstant composition 
(varying ratios of sodium to the zirconium), or was de- 
composed by the washing. 

The analyses, calculated on the dry basis, gave : — 



Zr 
Na 
C2O4 



IV. 
53'" 

9*i6 
3806 



V. 

4686 

410 

39"64 



VI. 

41*98 

1*07 

4295 



If the solution made with the excess of sodium oxalate 
was diluted considerably with water, a gelatinous precipi- 
tate was formed, very fine and insoluble. Precipitates 
were also formed by the addition of hydrochloric acid. 
This mode of forming the double oxalate was abandoned, 
and the following method was adopted with greater suc- 
cess. Zirconium hydroxide was dissolved in an excess of 
oxalic acid, and to this a concentrated solution of sodium 
hydroxide was added, bringing it nearly to neutralisation. 
When the solution was concentrated, an abundant crop 
of crystals was obtained on cooling, a good deal of heat 
being evolved in the mixing. Further evaporation yielded 
other crops of crystals. These were washed, dried be- 
tween filter-paper, and analysed. The results are given 
in the following table : — 



VII. 



VIII. 



IX. 



Calculated. 



Na .. .. 18*14 I7'46 1775 18*19 

Zr .. .. 12-59 i2*66 1278 ii'93 
C2O4 .. .. 69*27 66-89 6947 6988 

These results show a somewhat wide variation from 
those calculated. This probably arises from the faiftthat 
the fradlions were not composed of the crystals of a single 
kind of oxalate, but had other oxalates mixed with them 
in small amounts. Examined under a magnifying glass 
they seemed to be homogeneous, but the different crops 
could not be distinguished from one another. They were 
all small, hard prismatic crystals, somewhat diiBcultly 
soluble in water. One set of crystals, the analysis of which 
is reported under Vll. in the above table, was re-dis- 
solved in water and re-crystallised. On analysis it yielded 
the following results: — 

VII. XI. 



Na 18*14 

Zr 1259 



C2O. 



69*27 



i8 19 
12-71 
69-10 



These were calculated upon a water-free basis. The 
crystals from the various crops mentioned above did not 
contain a very constant amount of water, but ranged from 
913 to 11*06. The calculated amount of water in 
Zr(C204)2.3Na2C204.H2C204.5H20 is 10*62. It would 
seem, therefore, that the tendency, when this method of 
formation is adopted, is toward the formation of crystals 
containing free oxalic acid and with the sodium and zir- 
conium oxalates bearing a ratio of three to one. 

Zirconium Potassium Oxalate. 

The curdy precipitate gotten by precipitating zirconium 
chloride with normal potassium oxalate is insoluble in an 
excess of either of the substances. The precipitate first 
obtained is an impure zirconium hydroxide, containing 
only small amounts of oxalic acid. The supernatant 
liquid, on concentration, yields needle-like crystals of 
potassium oxalate, carrying only traces of zirconium. 
After the separation of a good deal of this potassium 
oxalate, further concentration yielded a gelatinous sub- 
stance having the composition (XII.) : Zr, 3934; K, 5*06; 
C2O4, 43*05 ; which seems to be a basic zirconium oxalate, 
mixed or united with a small proportion of potassium 
oxalate. If the potassium be calculated as potassium 
oxalate and subtracted, the composition of the remainder 
would be approximately Zr(0H)4.Zr(C204)2. 

On adding potassium binoxalate to a solution of zir- 
conium chloride a white curdy precipitate was obtained 
which was not completely soluble in excess of the 
binoxalate. The somewhat turbid solution was filtered 
and evaporated. Large crystals resembling those of 
oxalic acid formed. These were separated, and on ana- 
lysis proved to be oxalic acid. At the same time a 
number of small crystals were formed, which were 
mechanically separated, washed, and dried. These were 
analysed, and are reported under XIII. A further crop 
was gotten from the mother-liquor, and the analysts is 
given under XIV. 

XIII. XIV. 



Zr 19-59 

K 1618 

C2O4 64*23 



17*99 
1391 
68*09 



The curdy precipitate which first formed was also 
examined, and found to have the composition 
Zr{C204)2.2Zr(OH)4. 

The addition of a solution of potassium tetroxalate to 
zirconium chloride gave a gelatinous precipitate of zirco- 
nium oxalate (basic), carrymg a little potassium oxalate. 
Subtrading the potassium oxalate, the percentages (XVI.) 
Zr 39-09, and C2O4 38*63, are left, which are not very 
different from the figures gotten for the precipitate from 
potassium oxalate (neutral). 

This curdy gelatinous precipitate was dissolved in 
excess of tetroxalate, and the solution placed over 
sulphuric acid to crystallise, and yielded crystals having 
the composition (XVII.): Zr 20-85, ^ 1672, and C2O4 
62'3i. As will be seen, these are not far from the i : 2 
zirconium potassium oxalate, with excess of oxalic acid. 

When potassium hydroxide was added to a solution of 
zirconium oxalate in oxalic acid until nearly neutral, and 
then set aside for crystallisation, various crops of crystals 
were gotten, as in the case of the double sodium oxalates. 
These crops of crystals were similar in appearance to the 
sodium crystals. They were analysed and showed fairly 
constant composition. 

XVIII. XIX. XX. XXI. (KjCaOjj.kjCjO, 

Zr.. 18*08 19*25 I9'83 i8*47 ^8*95 

K .. 16-41 i6'35 14*84 14*46 i6*34 

C2O4 66-51 64*40 65*33 67*07 64*71 

The three previous analyses may also be referred to 
here as having approximately the same composition. (See 
Analyses XIII., XIV., XVII.). These are calculated as 
water-free. In the Analyses XVIII. and XIX. the per- 



ChSmical Nbws, > 
i March s, 1897. ' 



Photography of Rtpples^ 



»I5 



centages of water were iTgg and i2"38. These would 
correspond to the formula — 

(Zr(C204)2)2.(K2C2O4)2.H2C2O4.8H2O. 

In this case, as in the zirconium oxalates and the sodium 
oxalates, the crystals seem to form only along with free 
oxalic acid, giving acid salts. 

Zirconium Ammonium Oxalates. 
The addition of a solution of ammonium oxalate to the 
slightly acid solution of zirconium chloride gave a heavy 
gelatinous precipitate which was soluble in excess of 
ammonium oxalate, and proved to be zirconium hydroxide 
with more or less zirconium oxalate and small amounts 
of ammonia. The filtrate from this precipitate was 
evaporated slowly and a fine crystalline powder obtained. 
This contained (XXII.) Zt 42*17 -per cent, and C2O4 
39'86 per cent. This is in fair agreement with— 
Zr(C203)2.Zr(OH)4. 

When ammonium oxalate is added until the first gela- 
tinous precipitate is re-dissolved, and then evaporated to 
crystallisation, different crops of crystals can be gotten 
containing various amounts of ammonia. These did not 
seem to have any regular composition in our experiments, 
and were looked upon as basic zirconium oxalates with 
varying amounts of ammonium oxalate present. Thus 
for one of these the figures (XVIII.) Zr 3i'48, NH3 7'i4, 
and C2O4 6i'38 were gotten. 

Abandoning this method, and using the one adopted in 
the cases of the sodium and potassium double oxalates, a 
more favourable result was obtained. Zirconium hydroxide 
was dissolved in excess of oxalic acid, and then this was 
nearly neutralised by means of ammonium hydroxide. 
Analyses of these crops of crystals follow : — 



Zr . 
NH3 
C2O4 



XXIV. 

1655 
1446 
69-99 



XXV. 


2(NH4)aCa04 


1666 

13-35 
6999 


17-58 
I3"28 
68*94 



While these do not show that the crystals had been 
thoroughly purified, the results indicate that the composi- 
tion is one zirconium oxalate to two ammonium oxalate. 
On re-crystallising one of these crops of crystals, zirco- 
nium hydroxide was observed to separate when the 
solution was heated (to evaporate to crystallisation), and 
the crystals which were obtained consisted of ammonium 
oxalate alone. 

In general it may be stated that the zirconium oxalate 
fails to show any decided tendency to enter into clearly- 
defined combinations with the alkaline oxalates, exhibiting 
rather a power of crystallising along with them in mix- 
tures of any proportions. It can only be said at best that 
under the conditions of our experiments certain ratios 
seem to be preferred, and appeared more persistently. In 
all cases the crystals formed from oxalic acid solutions, 
and this free oxalic acid crystallised with them, giving 
acid oxalates. — yourn. Amer. Chem. Soc, xix., p. 12. 



Royal Institution. — A General Monthly Meeting of 
the Members of the Royal Institution was held on 
March ist, Sir James Crichton-Browne, M.D., F.R.S., 
Treasurer and Vice-President, presiding. The following 
were elefted Members : — F. J. Beaumont, Major C. T. 
Blewitt, R.A., J. F. L. Brunner, James Cadett, J. C. 
Carter, John Cohen, Mrs. Thomas Collier, J. G. Craggs, 
T. Donaldson, Henry Edmunds, Mrs. Henry Edmunds, 
G. S. Elliot, W. A. Frost, F.R.C.S., W. T. Garnett, J. P., 
H. A. Harben, Dr. F. Hewitt. F. W. Hildyard, Mrs. 
George King, H. Leitner, the Rev, J. D. Parker, E. .M. 
Preston, J. M. Richards, Colonel G. Sartorius, F. H. 
Schwann, Dr. W. R. Smith, H. A. Stern, C. J. Stewart, 
G. L. Stewart, Mrs. A. D. Waller, and Mrs. J. Lawsun 
Walton. 



PROCEEDINGS OF SOCIETIES. 

PHYSICAL SOCIETY. 
Ordinary Meeting, February 26th, 1897. 

Mr. Shelford Bidwell, President, in the Chair. 

Mr. J. H. Vincent read a paper on the " Photography of 
Hippies:' 

If mercury is used as the medium, all waves less than 
1*3 cm. long come under Lord Kelvin's definition of a 
ripple ; that is to say, they are waves whose lengths are 
less than such as are propagated \yith minimum velocity. 
Vibrations in mercury of about 200 per second and up- 
wards generate waves whose propagation is controlled 
almost entirely by surface tension, and these waves are 
therefore classed as " capillary ripples." Their speed of 
propagation is of the order of about one foot per second. 
They are invisible, owing to their high frequency, not in 
consequence of the velocity of their propagation. It is 
usual to examine them by some stereoscopic method. 

Mr. Vincent obtains photographs of the disturbed mer- 
cury surface by the sudden illumination of an eledric 
spark. The spark is about half a centimetre in length, 
and it lasts about one two-hundred-thousandth part of a 
second. Its brightness is increased by an auxiliary spark- 
gap. The optical arrangement consists of two lenses, 
one in the path of the incident light, and another to con- 
verge the reflecfted light from the mercury surface into a 
photographic camera. Ripples are set up in the mercury 
by a stylus attached to a tuning fork. For this purpose 
it is generally sufficient to give a slight blow to the 
prongs ; but when continuous vibration is required the 
tuning-fork can be connedted by a thread to an eledlrically 
driven fork, as suggested by Mr. Watson. 

The first photograph shows a series of circular waves, 
set up by a single stylus attached to a fork vibrating 180 
times a second. Fixed points at known distance, just 
above the mercury surface, enable the wave-lengths to be 
deduced from the photographs ; and, as the frequency is 
known, the surface tension may be easily calculated. 

In a second photograph, two styluses are attached to 
the same prong. Dark lines are seen to radiate from the 
region between the centres of oscillation; these are the 
lines of minimum disturbance — hypberolas, of which the 
centres of disturba,r;ice are the foci. This photograph 
illustrates " interference " similarly to the optical method 
of Young and Fresnel. 

A third photograph shows the formation of elliptical 
curves of disturbance, being the loci of the intersedlion of 
two series of circles, corresponding one to each of the two 
centres of vibration. Unlike the system of hyperbolas, 
these ellipses are not at rest, but travel outward from the 
sources. In order to render these ellipses stationary, it 
would be necessary to change one of the sources into a 
sink, towards which the circular waves might converge ; 
the photograph would then correspond to the optical 
device of M. Meslin, who obtains interference fringes 
by means of a screen placed between two point centres, 
one a source, and the other a sink. 

The phenomena of interference and diffradtion are well 
shown in a photograph of a point source and a refledling 
line. The refiedtor here is one side of a triangular piece 
of microscope cover-glass. The interference lines are due 
to the mutual adtion of incident and refiedled rays; they 
are analogous to Lloyd's single-mirror fringes. Other 
photographs exhibit analogues of " spherical aberration " 
and •' forced vibration." 

Mr. Vincent acknowledged his indebtedness to Mr. 
Boys for the recommendation of attempting the photo- 
graphy of capillary ripples. 

Mr. Boys congratulated the author upon the way in 
which the experimental difficulties had been overcome. 
The results would bear a good deal of close examination, 
and they would be found to present analogues of the 



ii6 



Animal and Vegetable Fats and Otis. 



greatest service in demonstrating the phenomena of 
acoustics and optics. Such photographs were far better 
than geometrical piftures drawn by instruments. For 
example, in the photograph illustrating the regions of 
minimum disturbance by lines radiating from a two-point 
source, it was easy to make out the positions where the 
two series of waves were half a period behind one 
another. The crests and troughs appeared as a set of 
dark and light concentric alternating circles, broken up 
into short arcs by radiating lines — the loci of minimum 
disturbance ; all the crests on one side of any particular 
radiating line were seen to correspond to troughs on the 
other side, so that the field of disturbance was mapped 
out as in acoustics. One set of phenomena yet awaited 
illustration by this photographic method, and that was 
" diffradion " from a grating. It might be possible to 
use as an exciter a comb with chisel-shaped points. He 
did not think it would be possible to go quite so far as to 
reproduce analogues of spedlral analysis. Since wave- 
length varies with surface tension, it was possible to vary 
the wave-length by dropping a little ox-gall or soap solu- 
tion upon the mercury surface. 

Mr. Blakesley asked why no refle<5tion8 occurred from 
the sides of the mercury retainer. 

Mr. Boys said the waves were lost at the edges of the 
meniscus. The mercury was kept in position by an an- 
nular ring of thin glass. 

Mr. Appleyard suggested that the analogue of refrac- 
tion might be obtained by an alteration of the surface- 
tension over a small area by amalgamation or other 
means. 

Mr. Vincent thought this could be done, but that it 
would be very difficult. 

The President proposed a vote of thanks to the author. 

Mr. Elder then read a paper by Mr. Beckit Burnie 
on " The Thermo-electric Properties of some Liquid 
Metals." 

The investigation was made with a view to determining 
the effeca of melting upon the thermo-eledric properties 
of certain metals. The metal to be tested is contained in 
a W-shaped glass tube, of which one limb can be cooled 
and the other heated. Thus one limb can contain molten, 
and the other solid, metal. Copper wires are plunged 
one into each limb, and through these connexion is made 
with a galvanometer. The thermal junctions, therefore, 
are copper-hot metal and copper-cold metal. The teni- 
perature is deduced from a separate thermal couple, cali- 
brated by a mercurial thermometer. Curves are drawn 
co-ordinating temperature and eledlromotive force. It is 
found that their slope depends upon the rate of cooling 
or heating of the metals ; this is particularly the case 
with bismuth. The effedl is attributed to the variation in 
crystalline strufture of the metal under test at different 
rates of solidification. With tin the change is less marked, 
and with lead it is unnoticeable. At or about the melting- 
points there is considerable change of slope in the curves. 
Here, again, the effedt is smallest for lead ; somewhat 
greater with tin; and remarkably large with bismuth, the 
latter changing from an exceedingly adtive thermo- 
eledtric metal to one resembling lead. A great change 
occurs also with mercury at the melting-point, indicating 
a difference in the Peltier effedt between solid and molten 
metals. 

A vote of thanks to Mr. Beckit Burnie was proposed by 
the President, and the meeting adjourned until 
March 12th. 



EDINBURGH UNIVERSITY CHEMICAL 

SOCIETY. 

Fifth Ordinary Meeting, February 8th, 1897. 

Dr. J. E. Mackenzie in the Chair. 

Mr. W. W.Taylor, M.A., B.Sc, read a paper on the 
" Electrolytic Dissociation of Water." 



I Chemical News, 
I March 5, 1897. 

The author began by describing the main principles of 
the theory of eledrolytic dissociation. 

The work of Kohlrausch in determining the aftual con- 
dudtivity of pure water was described in detail. 

The method adopted by Wijs for arriving at the disso- 
ciation grade from tlie hydrolysis of methyl acetate; that 
of Arrhenius and others from the balance between aniline 
acetate and water ; and, lastly, the numbers got by 
Ostwald and Nernst from the eleiSromotive force of a gas 
battery consisting of hydrogen eledtrodes in acid and 
alkali, were all treated of and carefully explained. 



Sixth Ordinary Meeting, February 22nd, 1897. 
Mr. W. W. Taylor in the Chair. 

Dr. Marshall gave a ledlure on " Electrolysis." 

A historical sketch of the subjeft from the end of last 
century till the present time was first given ; the inven- 
tion of the eledric pile by Volta, the decomposition of 
water by Nicholson and Carlisle, Davy's discoveries, and 
those of Berzelius, Faraday's laws, and the work of 
Daniell and Hittorf ; finally, the theory proposed by 
Arrhenius. 

The uses of eledtrolysis in chemical analysis were then 
considered, various examples being taken to illustrate this 
in reference to quantitative ele<5lrolysis. 

A brief mention was then made of the uses of eledlro- 
lysis in eledrotyping, eledtro-metallurgy, and the purifica- 
tion of such metals as copper. 

A seledlion was made both from inorganic and organic 
substances to show how certain syntheses could be con- 
du(5ted by eledtrolytic means. 



NOTICES OF BOOKS. 



A Practical Treatise on Animal and Vegetable Fats and 

Oils. By W. T. Brannt. (Second Notice). Vol. II. 

Philadelphia : H. C. Baird and Co. London : Sampson 

Low, Marston, and Co., Ltd. i8g6. 
We find here firstly the conclusion of the account of the 
non-volatile or fatty oils. The efficacy of boiling as 
applied to linseed oil is traced to the expulsion of muci- 
lage. It is remarkable that in some parts of Russia and 
Germany cold-drawn linseed oil is used as a table-oil and 
in cookery. 

The produdtion of sunflower oil for industrial uses in 
Russia is steadily increasing. 

Nut-oil, expressed from the walnut, dries better even 
than linseed oil, and is preferred for artistic uses. Sperm 
oil has an advantage over most oils, as its sophistication 
is exceedingly difficult. The nature of ambergris is still 
a disputed question ; some authorities considering it as 
a pathological secretion of the urinary bladder, whilst 
others regard it as merely the indurated faeces of the 
animal. 

The remarkable penetrative power of doeglic oil was 
put on record as early as 1250. The credit of first obtain- 
ing cod-liver oil, colourless, not in virtue of any artificial 
bleaching, but of the total freedom from putrefaction, 
seems to belong to Peter Moller. Eulachon oil is preferred 
by some physicians as being more digestible than cod- 
liver oil. 

Fish-waste is a most valuable source of artificial 
manure, and is capable of much extension. It is con- 
duced chiefly in the Lofoten Isles, at Newfoundland, and 
on the coasts of the United States. 

Borneo tallow, obtained from trees of the genus Hopea, 
is a lubricating agent far preferable even to olive oil. 
The cultivation of the tree deserves attention. 

Cacao-butter, one of the produdls of Theobroma cacao. 



CBBUICAL NBWBi I 
March 5. 1897. I 



Chemistry of Dairying. 



117 



and not of Cocas mucifera or of Elais guineensis, has an 
exceptional power of resisting rancidity, but it is scan- 
dalously sophisttcated with produCls which have no such 
properties. The original home of the cocoa-nut (better, 
to avoid confusion, cocos nut) is corredlly stated as being 
the Malay and the South Sea Archipelago. 

It is satisfadtory to find that the leading manufadurers 
and merchants are discouraging the term " refined lard " 
as applied to adulterated produds. 

On the subjedt of butters, as judged by Hehner's test, 
our author holds that samples with 88 per cent of inso- 
luble fatty acids may be pronounced " pure," those with 
a higher percentage" suspicious," and with over 8973 per 
cent "adulterated." We regret to find " titer " used in 
place of " standard." 

Among the waxes, next to bees-wax, Chinese wax 
{ceryl cerotate) is said to possess " ten times the illumi- 
nating power of ordinary candles." 

Waste fats include a variety of industrial produds, one 
of the most important being the Yorkshire grease 
recovered from the waste waters of fulling mills. Its 
removal from the town sewage, and ultimately from the 
streams, is a necessary preliminary to the purification of 
the latter. 

The bleaching of fixed oils and fats is explained very 
carefully. The chemical procedures were first introduced 
by Berthollet, though chlorine, which he proposed, has 
since been superseded by hydrogen peroxide, and in some 
cases by chromates mixed with hydrochloric acid. Animal 
charcoal is not well adapted for bleaching oils. 

The successful application of feeble elecSlric currents 
for bleaching oils seems to be due to L. Levat, of Aix. 
Acids could not be entirely removed in this manner from 
inferior lubricating oils. 

Artificial butter was first produced by Mege-Mourier, 
under the auspices of Napoleon III. It is somewhat 
remarkable that whilst the Governments of France and 
Germany have encouraged the manufafture and sale of 
margarine, of course, under the proper regulations to 
prevent fraud, in the United States it has been opposed 
and persecuted in every pradicable way. Eminent 
chemists, physiologists, and physicians, after long and 
careful courses of experiment, have decided that margarine 
has no unwholesome properties, and that it is less disposed 
to turn rancid than normal cow-butter. 

Into the essential or volatile oils, their preparation and 
their distin(Stive charaders, space does not allow us to 
enter. 

We can strongly recommend this work to the vast and 
varied industries with which it is concerned. 



The Chemistry of Dairying ; An Outline of the Chemical 
and Applied Changes which takes place in Milk and in 
the Manufadure of Butter and Cheese; and the 
Rational Feeding of Dairy Stock. By Harry Snyder, 
B.S., Professor of Agricultural Chemistry, University 
of Minnesota, and Chemist of the Minnesota Experi- 
ment Station. Easton, Pennsylvania : Chemical Pub- 
lishing Co. 1897. 
The appearance of this book is explained and justified 
by the change which, within the last few years, has 
occurred in dairying. From a mere rule-of-thumb trade 
to an industry which, to be successful, must be conducted 
on scientific principles, or, at least, in accordance with 
fadls scientifically determined. 

In the chapter on the " General Composition of Milk," 
the reader is reminded that milk-fat and butter are not 
identical. Milk-fat is the pure dry fat, free from water, 
casein, or salt, all of which are present in butter to the 
extent of about 17 per cent. 

For testing milk the Babcock method is recommended 

as trustworthy for whole milk, but as less reliable for 

butter-milk and skim-milk. Milk when partially frozen 

is not in a condition to be sampled. 

The use of pure cultures, or as they are here called 



" starters," seems to be attracting attention in America 
for the ripening of cream. 

The results of the lactometer are shown as liable to 
error on account of the complex composition of milk. 
Cream itself is variable, as it may contain as much as 60 
per cent of fat. The higher the temperature reached in 
churning, washing, and working, the less is the proportion 
of water retained in the butter. 

We find here no mention of the vegetable matters 
which in cheese-making may be used as substitutes for 
rennet. 

It will be remarked here that in America a difference 
seems to be made between oleo-margarine and butterin, 
the former being harder and less fusible. With us this 
difference does not obtain, oleomargarine being the name 
recognised by the law. It may here be noted that the 
butter now obtained from the milk of the cocoa-nut is 
more digestible than cow-butter. 

This very useful manual is addressed not to experts, 
but to young men preparing themselves for the position 
of the dairy-farmer. 



Engineering Chemistry ; A Manual of Quantitative 
Chemical Analysis for the Use of Students, Chemists, 
and Engineers. By Thomas B. Stillman, M.Sc, 
Ph.D., Professor of Analytical Chemistry in the 
Stevens Institute of Technology. With 154 illustra- 
tions. Easton, Pennsylvania : Chemical Publishing 
Company. 

The Publishing Company of Pennsylvania is decidedly 
earning a high and well-merited regulation for the produc- 
tion of works on technical chemistry. The title of the volume 
might with advantage be somewhat modified. Perhaps we 
might suggest "Manualof Quantitative Analysis, especially 
arranged for the Use of Engineers." But there is one 
sedtion which could not be legitimately placed under 
such a caption. We refer, of course, to the copious and 
ably-written instrudtions for the sanitary analysis of 
water, a subjedt belonging to the medical pradtitioner, or 
the chemist truly so-called, rather than to the engineer. 
Here, however, we find no mention of the "tintometer" 
which is generally found preferable to the various calori- 
meters. Much of the matter on soaps can scarcely be 
called engineering chemistry. 

On the other hand, something might have been usefully 
added to the remarks on filters. The Pasteur filter, 
which is generally found the best— at least for work on 
a domestic scale — does not seem to be mentioned. 

The reader will be fully aware that the weights used in 
the United States of America are identical with the 
British standards. But this agreement unfortunately 
does not extend to the measures for liquids. The 
American gallon is about equal to the old English wine 
gallon. The obstinacy with which America, like France 
and Germany, clings to Baume's hydrometer is painful. 
If there is any occult reason why commercial men should 
not or cannot use the diredt specific gravity scale, why 
not use Twaddle, which exists only in one type, and 
which is easily and simply re-calculated into diredt 
specific gravity ? 

Engineers will find this book a most useful and trust- 
worthy guide. 

Report on the Teaching of Chemistry by a Special Sub- 
Committee appointed by the Technical Education Board 
of the London County Council, November 23rd, 1896. 
We hope that in our endeavours to realise a worthy 
standard of education in this country, we shall not 
remind the world of the too many cooks who spoiled the 
broth. We can scarcely enumerate the various public 
and semi-public bodies who have their fingers in John 
Bull's pie. Some boards and committees concerned are, 
if we consider their origin, little likely to play a very 
salutary part. But some of the gentlemen whose opinions 



Ii8 



Bread and Panification, 



IOhbmical Nbws, 
\ March 5, 1807. 



are here put on record are fully qualified to speak on 
higher education, and deserve a respedtful hearing. 
Thus, Mr. D. Howard, Dr. Armstrong, and Dr. Tildendo 
not consider that examination seledls the best students. 
" The best thing to be done in London to promote this 
higher instrudtion is to extend the system of senior 
scholarships." These scholarships should on no account 
be awarded as the results of an examination, but as the 
personal recommendation of the professors upon whom 
the responsibility must be thrown of nominating only 
students of promise. Such scholars after about two years 
of special training in research should be able to work by 
themselves." " A person who is studying for the B.Sc. 
degree is handicapped as far as pradtical work is con- 
cerned, as he has to cram for his examinations. The 
boys cannot be picked out by mere examination, but by 
careful observation of their work, bcholarships gained 
by examination have done higher education a good deal 
of injury." 

In short, a careful survey of the opinions expressed by 
the authorities here quoted shows more than ever that the 
blind reliance on examinations as a test of merit is nearing 
its end. " The seledion should rather be determined by 
the recommendation of the head master of the school 
from which a pupil may proceed, based on the work of 
the candidate throughout his whole school career. 

This is substantially the system which has worked so 
successfully in Germany. 

The conclusions drawn from the evidence submitted 
are: — 

1. That chemistry is a valuable subjedl for school 
teaching. 

2. That it should be preceded by elementary courses 
of physics, 

3. That the work should be always largely pradtical. 

4. That no attempt should be made to impart in 
schools any knowledge of the application of chemistry 
for commercial purposes. 

5. That in seledling candidates for the higher science 
training a written examination is insufficient and inad> 
visable. 

This report is worth the most careful attention of all 
who are or aim at becoming authorities on national 
instruction. 



Selection of Procedures for the Analysis of Fuels, Iron 

Ores, Castings, Steels, and Irons. (Recueil de Procedes 

de Dosage pour I'Analyse des Combustibles, des 

Minerals de Fer, des Pontes, des Aciers, et des Fers). 

By G. Arth, (Professeur de Chimie Industrielle a la 

Faculte des Sciences de Nancy. Paris : G. Carre and 

C. Naud. 8vo., pp. 313. 1897. 

The present development of the iron and steel manu- 

fadtures, and the extension of the industrial applications, 

has naturally led to the appearance of such works as that 

before us. 

The author tells us in this preface that he does not offer 
a treatise on analysis, but merely a seledion of the pro- 
cedures in use in the principal siderurgical establishments 
and of other methods which it may be useful to know. 
He remarks that industrial analyses are of two different 
kinds. On the one hand easy and rapid methods for 
daily use, and on the other difficult procedures for estab- 
lishing the composition of substances taken as types, or 
for checking doubtful results or such as have been the 
subjedt of dispute. 

No fewer than 60 pages are here devoted to the assay 
and analysis of fuels. The exa(Sl difference between 
assay and analysis is scarcely as clear as it might be 
desirable. " Assay " may mean either a qualitative 
operation, or perhaps the determination of some leading 
ingredient. He determines phosphorus in the ashes of 
the fuel by means of the molybdenum method. 

He determines the calorific power of a fuel by calori- 
metric methods, using the bombs of Hempel, of Mahler, 



and Berthelot. A whole page plate shows the installation 
of the bomb at the Chemical Institute of Nancy, whilst a 
table exemplifies the calculation. 

There is also an account of the determination of calori- 
metric power by evaporation, and experiments in the 
boilers of industrial establishments. Three steam units 
may be employed, those of Rankine, Brix, and Hartig, 
equal respedively to 537, 540"6, and 552*2 cal. Then 
follows an account of the values of gaseous fuels ; to wit, 
the gases of gazogens, of blast furnaces, the gaseous 
mixtures of the Dawson system. A chapter is also 
devoted to gas analysis, i.e., gases not employed as fuels 
but still summed up under the head assay and analyses 
of combustibles. 

The second part is occupied with the " assay and 
analysis of ores," mainly, of course, those of iron. The 
analysis of titaniferous irons is, however, explained at 
some length according to the indication of Posti. It is 
remarked that the presence of titanic acid introduces 
several causes of error in determinations executed in the 
ordinary manner. It is also stated that oxygenated water 
is an excellent reagent for detecting the presence of 
titanic acid, as in acid solutions containing this titanic 
acid it produces a fine orange-yellow. 

A third part of the work discusses the analysis of 
metallic produtfts, iron castings, and steels. There is 
also the procedure of T. Parry and J. J. Morgan for the 
analysis of titanium, and the determination of phosphoric 
acid in basic slags. 

Bread and Panification ; Chemistry and Technology of 
Baking and Grinding. (" Le Pain et la Panification 
Chimie et Technologie de la Boulangerie et de la 
Meunerie"). By LfioN Boutroux, Professeur de Chemie 
Doyen de la Facult6 des Sciences de Besan^on. 
Paris : J.B. Bailliere et Fils. Pp.358. 1897. 
France has long been distinguished for its eminence in 
the art of baking and all the collateral branches. 

Hence, an author who combines the traditional skill 
of his country with a full insight into the results of 
of modern Science is well worthy of our careful attention. 
Professor Boutroux, moreover, has not confined his 
studies to French authorities, but has utilised the treatises 
of Birnbaum and Jago, so that he is able to lay before his 
readers the full results of the experience of the day. 

From an analysis here given of wheats as produced in 
different countries we find the highest rank in percentage 
of gluten and albumen belongs to a Polish wheat, namely, 
21*5 per cent, whilst the second place falls to Egyptian 
wheat with 2o"6 per cent. If we contrast these figures 
with the white provincial wheat of 9*8, we shall not con- 
clude that temperature and latitude are main fadlors in 
the growth of superior wheats. In a dry season, how- 
ever, the nitrogen is much higher than in medium and 
moist years. 

The different parts of the grain are by no means chemi- 
cally identical, and vary in consequence in their physio- 
logical adlivity. The " entire flour " so much valued in 
Britain owes its laxative properties — annoying and even 
dangerous to some persons if beneficial to others — to the 
soluble matter of its coatings. 

The use of rollers in milling was first applied in Hun- 
gary about 1874, and established itself in Western Europe 
since 1878. 

The theory of panary fermentation is thus summed up. 
It consists essentially in an alcoholic fermentation by 
means of yeast and of the sugar pre-existing in the flour. 
According to Bibra's analyses of bread the composition 
and even the reactions difl^er greatly. Some white breads, 
e.g., those of St. Petersburg, are neutral. The rye bread 
of Niiremburg and of Stockholm is acid ; so is also the 
notorious pumpernickel of Westphalia, a whole-meal 
bread containing a little extra bran. A still inferior bread, 
Keilchen, is made in some parts of Saxony and Silesia. 
The frauds committed by, or ascribed to, bakers are 



Crruical Nbws, I 
March s, 1897. I 



Chemical Notices from Foreign Sources. 



119 



classified as — (i) The use of an excess of water ; (2) the 
use of damaged flours ; (3) the addition of alien flours ; 
and lastly (4), tha addition of saline waters other than 
sodium chloride. 

This book will prove very valuable to public analysts, 
medical officers of health, and pharmacists. 

Conspectus of Chemical Analysis. Part I.— Qualitative 
Analysis. (" Precis d'Analyse Chimique." Premiere 
Partie. — Analyse Qualitative). By E. Fink, Chef des 
Travaux Pratiques d'Analyse a I'Ecole de Physique et 
de Chimie Industrielle a la Ville de Paris. Paris: 
Georges Carres. 1896. 
This little manual describes, in the first place, the re- 
actions in the dry way, and then the reagents employed 
in the solid and in the liquid state. The author then 
proceeds to the assay, and in the dry way, including the 
use of the spedtroscope. Next follows a classification of 
the metals from an analytical point of view, in which we 
perceive that not a few of the rarer substances are 
omitted. Next we come to the readlions of the acids, 
classified as the sulphuric, the hydrochloric, the nitric, 
the oxalic, the succinic, and acetic groups. 

What may be called an Appendix treats of the prepara- 
tion of the substances to be analysed, the systematic 
procedure for the detection of bases and acids, and the 
arrangement of the results. 



CORRESPONDENCE 



HOW SOON SHALL STUDENTS BEGIN THE 

STUDY OF QUALITATIVE ANALYSIS? 

A Rejoinder. 

To the Editor of the Chemical News. 
Sir, — We perused Mr. Beebe's article on the above 
question with interest, but we are quite unable to agree 
with the conclusions he draws. 

Mr. Beebe has three objedtionsto the student beginning 
his laboratory course with the study of the preparation 
and properties of simple gases, &c. We take these ob- 
jections in order. 

1. " The experiments are dangerous." Quite true, if the 
manipulation is careless ; but is not a careless student 
just as likely in qualitative analysis to send half a test- 
tube of hot acid into his neighbour's face, as to blow him 
up with a flask of impure hydrogen when preparing that 
gas ? And if a spirit of recklessness is abroad in the 
laboratory, whose fault is it? Mr. Beebe mentions hy- 
drogen and phosphorus especially, in this connexion. If 
the former be prepared in & small flask, and not a WoulfFs 
bottle, the danger is lessened. All experiments, too, can 
be performed with small quantities of the gas ; and the 
combustion of hydrogen, to show the produdion of water, 
is of course left till late in the lesson, when the flasks are 
free from air. Students should be warned of any dangerous 
practice. 

Phosphorus need not be burned in oxygen, since carbon 
and sulphur could be used, but small fragments may very 
well be given out by the demonstrator as required, and the 
experiment performed. 

Here, in an organised science school, we have classes 
of boys and girls, from eleven to fourteen years of age, 
working two lessons a week, and no accident whatever 
has occurred under the new Science Syllabus for the past 
two years. 

But, assuming that such a course is dangerous, we fail 
to see that practice in warming liquids in test-tubes, or in 
flltering off precipitates, trains a student to handle the 
evolution flask or the deflagrating spoon. An hour's drill 
in the fitting up and corre(5t use of apparatus would ac- 
complish far more in this respedt. 

2. Unconnectedness. By this term Mr. Beebe would 
apparently have us understand that opportunities for 
revision are wanting in the course he condemns. His 



ideal seems to be after a " This-is-the-house-that-Jack- 
built" principle. A series of lessons dealing with non- 
metallic elements can be made to follow one another in 
logical sequence, and when twelve have been covered it 
is a good plan to repeat them. But the constant repe- 
tition, such as is obtained in qualitative analysis, soon 
produces mechanical work, and has then little educational 
value. 

3. Interest. This can certainly be well maintained by 
the course Mr. Beebe criticises. Variety is always inte- 
resting, and the preparation of simple gases, supplemented 
by easy quantitative experiments, gives far more scope in 
this direction than does qualitative analysis. Our young 
students give unmistakable proofs that they find their 
work here interesting. 

Again, Mr. Beebe says that the student should have a 
good knowledge of the preparation and properties of non- 
metallic elements before— or at any rate while— he is en- 
gaged in qualitative analysis. Our experience is that 
this knowlege is very slowly gained from " leCtures," no 
matter how ably " illustrated by experiments " they may 
be. What things of mystery our chemical ledtures were 
to us as youngsters twenty years ago ! But direCtly a 
student begins to do the experiments for himself, and 
record his own observations and inferences in his note- 
book, the assimilation of this knowledge proceeds apace. 

Finally, is there nothing to be said as to the relative 
educational value of the two systems ? We would train 
our pupils to be deft in manipulation, keen to observe and 
discriminate, and accurate in drawing an inference. 

The use of test-tubes and reagent bottles, the colours 
and appearances of precipitates, do not carry us far 
towards such a goal, while the " inferences " are mainly 
matters of memory. That which by constant repetition 
is performed mechanically ceases to have any value as a 
mental exercise, and young students soon acquire a very 
mechanical way of " getting out" salts. 

But, on the other hand, in determining the properties 
of a common gas, the pupil's attention is kept on the qui 
Vive all the lesson ; he has fresh observations to chronicle 
and new inferences to draw continually, while the arrange- 
ment and fitting up of his varied apparatus cultivates his 
manipulative powers. Nor must the quantitative side be 
forgotten. A lad of twelve, who has worked with us six 
months, with one pradlice lesson weekly, has just found 
experimentally that 145 m.grms. of mercuric oxide, when 
heated in a combustion-tube, give off 6'2 c.c. of oxygen, 
and leave a residue of mercury weighing 133 m.grms. 
Such an exercise has done more for his education than 
the qualitative analysis of half-a-dozen simple salts. — 
I am, &c., 

H. WiGLEY, 6. A., F.C.S. 
Winsford. 

CHEMICAL NOTICES FROM FOREIGN 
SOURCES. 

Comptes Rendus Hebdomadaires des Seances, dePAcademie 
des Sciences. Vol. cxxiv., No. 5, February i, 1897. 

Constitution of the Combination of Antipyrine 
with the Phtnols.— G. Patein. — The author infers that 
— I. Monomethylphenyl pyrazolone does not combine 
either with phenols or acid phenols. 2. Of the two 
atoms of nitrogen in antipyrine, the nitrogen i, being 
entirely in the same relations in the mols. of dimethyl 
pyrazolone and of monomethyl pyrazolone, antipyrine 
fixes the phenols by means of nitrogen 2. 3. The exist- 
ence of the combinations of antipyrine and the phenols 
cannot be reconciled wieh the supposition of E. von 
Meyer, according to which antipyrine might be considered 
as a sort of betaine. 

Determination of Lipase. — MM. Hanriot and Camus. 

Separation of Glycerin in Wines by Elimination 
in Watery Vapours. — MM. F. Bordas and Sigoda 
Raczkonski. 



120 



Meetings for the Week, 



(CHBMICAL ftEWS, 

1 March 5, 1897. 



NOTES AND QUERIES. 

%* Our Notes and Queries column was opened for the purpose of 
giving and obtaining information likely to be of use to our readers 
generally. We cannot undertake to let this column be the means 
of transmitting merely private information, or such trade notices 
as should legitimately come in the advertisement columns. 

Purifying Mercury. — I shall be obliged if any correspondent can 
tell me how to purify a quantity of mercury I have got. Some zinc 
has been dissolved in it. I have no apparatus tor distilling the mer- 
cury properly, so that method is impracticable. At present the mer- 
cury adheres to glass, and so is useless for a large number of experi- 
ments. — J. MacGregor. 



MEETINGS FOR THE WEEK. 

ToBBDAY, gth.— Royal Institution, 3. " Animal Eleftricity," by 

Prof. A. D. Waller, F.R.S. 
Wbdnbsday, loth.— Society of Arts, 8. "The Prevention of Fires 
Due to the Leakage of Eleftricity," by Frede- 
rick Bathurst. 
Thursday, nth. — Royal Institution, 3. " Greek History and Extant 
Monuments," by Prof. Percy Gardner, F.S.A. 

Society of Arts, 4.30. " Prevention of Famine in 

India," by Sir Charles A. Elliott, K. C.S.I. 
Friday, 12th. — Royal Institution, g. " The Source of Light in 
Flames," by Arthur Smithells. B.Sc. F.I.C. 
— — Physical, 5. " Mechanical Cause of Homogeneity of 

Strufture and Symmetry Geometrically investi- 
gated, with special application to Crystals and 
Chemical Combination," by William Barlow. 
Saturday, 13th. — Royal Institution, 3. '* Eleftricity and Electrical 
Vibrations," by Right Hon. Lord Rayleigh, M.A., 
F,R.S. 



THE MANUFACTURE 

OF 

EXPLOSIVES. 

A Theoretical and Pradtical Treatise on the History, the 
Physical and Chemical Properties, and the Manufa(fture 

of Explosives. 
By OSCAR GUTTMANN, Assoc. M.Inst. C.E., F.I.C. 
Member of the Societies of Civil Engineers and Architefts of Vienna 
and Budapest. Correspondent to the Imperial Royal Geological 
Institution of Austria, &c. With 328 Illustrations. In Two Volumes, 
Medium 8vo. Price £2 2s. Uniform with the Specialist's Series. 

" In these handsome volumes the author has placed on record, for 
the benefit of his professional brethren, the results of many year's 
experience in the manufacture of explosive substances." — Engineer. 

" A work of such nnagnitude and importance, that it will un- 
doubtedly take a leading place in the literature on the subject." — 
A rms and Explosives. 

"This work commends itself most strongly to all manufac- 
turers and users of explosives, and not less to experts." — Chemical 
News. 

'• The work is full of valuable information."— AfawcAesier Gnardian. 

London: WHITTAKER & CO., Paternoster Square^^.C. 

AGRICULTURAL CHEMICAL ANALYST S. 

By H. W. Wiley. Vol. I., SOILS, 15s. Vol. II., 
FERTILIZERS, 8s. Vol. III., AGRICULTURAL 
PRODUCTS, 15s. 

ENGINEERING CHEMISTRY. 

By J. B. Stillman. Cloth, i8j. 

THE CHEMISTRY OF DAIRYING 

By H. Snyder. Cloth, 6s. 

THE CHEMISTRY OF POTTERY. 

By Karl Langenbeck. Cloth, 6s. 

DEVELOPMENT OF THE PERIODIC LAW. 

By F. P. Venable. Cloth. los. 

CHEMISTRY FOR BEGINNERS. 

By Edward Hart. Cloth, 6s. 

Circulars on application. 

CHEMICAL PUBLISHING CO. 
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without restriftion as to age or place of previous study ; but preferably 
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A copy of the scheme, giving particulars of tenure, &c., under 
which the Fellowships will be awarded may be had on application at 
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Street, London, E.C. 

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Estimation of Sulphur in Irony Steel, and Sulphides of Iron. 121 



THE CHEMICAL NEWS. 

Vol. LXXV., No. 1946. 

VOLUMETRIC ESTIMATION OF SULPHUR 

IN IRON, STEEL, AND SULPHIDES OF IRON. 

By G. G. BOUCHER. 

There is only one volumetric process, I believe, for the esti- 
mation of sulphur in iron and steel in general use, viz., the 
iodine method. It is fairly accurate and quick, but has one 
great disadvantage — the solutions do not keep well. If 
kept for any length of time they lose their strength, 
especially if exposed to sunlight, and consequently have 
to be frequently re-standardised. It occurred to me that 
if it were possible to obtain a process where only one 
solution is used, and that one a solution which would 
keep its strength for any length of time, it would be a 
distindt advantage. 

This I found could easily be done ; and the following 
process will, with care, be found to give very good results, 
which will compare well with those given by the iodine 
method. 

The apparatus used in this method is the same as that 
used in the iodine process. 

From 10 to 15, or even 20, grms. of iron or steel are 
weighed out into a flask, which is then connedled to the 
U-tube. Fifteen c.c. of a solution (strength 5E) of NaHO 
are run into the U-tube, and then sufficient HCl (strength 
5E) run into the flask to dissolve the iron. The flask 
and contents are gently heated, and when the metal has 
completely dissolved the solution is heated to boiling. 
The U-tube is now disconne(5ted, and the contents run 
slowly into an acid solution of Fe2Cl6. H2S is liberated, 
and a portion of the iron is reduced. The reduced iron 
is then estimated by a standard solution of K2Cr207, and 
it will be evident from the formulae below that each c.c. 
of K2Cra07 used will be equivalent to a certain quantity 
of sulphur. 

(i). Fe2Cl6 + H2S = 2FeCl2+2HCl+S. 
(2). 6FeCla+K2Cr207+i4HCl = 

= 3Fe2Cl6-|-2KCl + Cr2Cl6+7H20. 

By dissolving 3"o65 grms. of K2Cr207 in 1000 c.c. of 
distilled water, a solution is obtained i c.c. of which is 
equivalent to o'ooi grm. sulphur. A solution of twice 
this strength is used for the estimation of small quantities, 
but when the sulphur is believed to be above o"i5 percent, 
it is advisable to use a stronger solution, and the standard 
solution used in the analysis of iron ores is used, i c.c.= 
0'0057i grm. of sulphur. 

The ferric chloride solution used is made by adding a 
solution of ferric chloride, containing o'l grm. of iron in 
I c.c, to 50 c.c. of hot HCl (strength 5E). The amount 
of ferric chloride required should be calculated, as it is 
not advisable to have a large excess ; about 0'5 or i c.c. 
is usually found sufficient. 

The bichromate solution can be standardised by pure 
iron wire or ferrous ammonium sulphate, but a better 
method is to dissolve about 15 grms. of iron or steel, in 
which the sulphur has already been determined gravi- 
metrically, and treat the metal as described above. The 
amount of bichromate required to oxidise the reduced 
iron, divided by the amount of sulphur known to be pre- 
sent in the 15 grms. weighed out will give the value of 
each c.c. in sulphur. 

Sulphur in Sulphides of Iron. 
If the sulphide is soluble in HCl, 0*5 grm. is weighed 
out into a 300 c.c. flask, dissolved in about 40 c.c. HCl 
(strength 5E), and treated in the same way as iron. If 



the sulphide is insoluble in HCl,o'5 grm. is weighed out 
into a porcelain crucible and mixed with an excess of pure 
iron (6 grms.). The crucible is then filled up with ground 
charcoal, covered with a lid, and heated to redness in a 
muffie with a closed door for ten or fifteen minutes. The 
crucible is then taken out, allowed to cool, the contents 
emptied into a 300 c.c. flask and treated as soluble 
sulphide. 

It is advisable to make a blank experiment, using the 
same quantity of iron, &c., required by this method. The 
iron is sure to contain a little sulphur, which would make 
the results appear higher than they should be. Below I 
give some analyses by this method. 





Bessemer Iron, 








Gravimetric method. 


KjCr,0, method 




S per cent. 




S per cent. 


Sample i 


.. .. 0-04I 




0*038 


.. 2 


. „ .. 0-015 




0*017 


.. 3 


. . . 0'020 




0023 


., 4 


. . . 0-028 

Mottled Iron. 




0*030 


Sample i 


. .. 0*312 




0320 


11 2 


.. 0*411 




0*399 


.. 3 


. . . 0*295 




0*296 


.. 4 


. . . 0*384 




0*387 


Sulphides of Iron (Insoluble). 




Sample i 


.. .. 48*61 




49*25 


2 


. . . . 30*68 




30*97 


.. 3 


. .. 3256 




32*14 


.. 4 


.. .. sro 




51*10 


.. 5 


. . . 0*707 




0773 



The process is a quick one ; an analysis of iron, steel, 
or sulphide for sulphur can be made comfortably in about 
half or three-quarters of an hour. When the percentage 
of sulphur is very low considerable care is required at 
the finish of the process ; the indicator should show no 
sign of any blue colour for the space of one minute. 

I tried this method on a sample of copper sulphide with 
the objedl of seeing whether it would be possible to deter- 
mine the sulphur volumetrically. I expeded that some 
of the sulphur would be detained by the copper, but 
thought the experiment worth trying. The copper sul- 
phide was first heated with pure iron in a muffle, and 
afterwards treated just as sulphide of iron. The results 
I give below : — 

Copper Sulphide. 



Gravimetric process. 
S per cent. 

Experiment I.. .. 24*0 
„ 2.. .. 24*0 



Volumetric process. 
S per cent. 

22*30 
2274 



The idea of heating the iron sulphide with pure iron in 
a muffle is not mine; it is a process devised by F. P. 
Tread well, and can be found in the journal of the Chemical 
Society, vol. Ix. 

Laboratory, North Lonsdale Iron Works, 
Ulverston. 



ESTIMATION OF BORIC ACID IN FOODS. 

By L. DE KONINGH. 

The estimation of boric acid, at one time very trouble- 
some, has become quite an easy matter since the discovery 
that it may be accurately titrated in presence of glycerol 
with phenolphthalein as indicator. To apply the process 
to articles of food (and I will confine myself for the pre- 
sent to milk and uncooked eggs) some few precautions 
must, however, be taken. 
Boric acid is seldom used alone, but mostly in admixture 



122 



Electric Shadows and Luminescence, 



( Crbuical News, 
( March I2, 1897. 



with borax, a mixture of three parts of the acid with one 
part of ground borax, constituting the article known as 
glacialine. In pradlice it is, however, in my opinion, not 
necessary to make a distindtion between the acid and its 
sodium salt, as both are no doubt equally harmless in 
small quantities; but if the amount of either reaches 
I per cent or more the time has come for a protest. 

When testing uncooked eggs (the entire contents beaten 
up] for boric acid, I take 5 grms. of the sample, add one 
drop of sodium hydroxide (i : i), dry, and finally incine- 
rate. The char is then powdered, boiled with water, and 
the residual black mass again burnt. The ash is also 
boiled with water, and the two solutions are united. The 
liquid is now faintly coloured by methyl orange, and tenth- 
normal sulphuric acid is added until a faint pink is ob- 
tained. The solution is now boiled for a minute to expel 
carbon dioxide, cooled, mixed with one-half of its bulk of 
glycerol, and titrated with tenth-normal sodium hydroxide, 
with phenolphthalein as indicator. Although it is now 
admitted that in presence of glycerol the amount of acid 
may be calculated from the number of c.c. of sodium 
hydroxide used, I prefer to check my sodium hydroxide 
with pure crystallised boric acid, using about the same 
quantity as present in the sample, and mixing this up 
with exadtly the same amount of glycerol and water. 
Working in this manner the estimation of boric acid is, 
as regards accuracy, second to none. 

It must, however, be remembered that eggs contain a 
small quantity of alkaline phosphates, and that phosphoric 
acid behaves somewhat like the boric acid. A method of 
removing this acid has already been proposed and is based 
on the insolubility of calcium phosphate and the compara- 
tively large solubility of the borate. I find, however, 
that in uncooked eggs there is just enough phosphoric 
acid to account for 3 cc. tenthnormal sodium hydroxide, 
when working on 5 grms. of sample, so I now propose to 
dedudt 3 c.c. of sodium hydroxide from the number of c.c. 
taken by the sample. I scarcely need point out the neces- 
sity of proving the acid by the alcohol test. As a rule the 
presence may be ascertained by simply stirring some of 
the sample with a drop of sulphuric acid and a little spirits 
of wine and then setting fire to it. 

When dealing with milk I allow i c.c. of sodium 
hydroxide for every 10 grms. of the sample. If the 
amount of acid is, as usual, very small, no particular 
accuracy can be claimed for the process ; but if present 
in larger, and consequently harmful, quantity, the results 
are all that may be desired. — journal of the American 
Chemical Society, xix., No. i, p. 55. 



ELECTRIC SHADOWS AND LUMINESCENCE.* 

By Prof. SILVANUS P. THOMPSON, D.Sc, F.R.8., M.R.I. 
(Continued from p. 113). 

Having touched all too briefly upon the researches of 
Lenard, it remains for me to speak of those of Wiede- 
mann, of Erlangen, who for many years has made a study 
both of the phenomena of ele(5lric discharge and of those 
of fluorescence and phosphorescence. In a research 
made in the year 1895 he attained some results of singular 
interest. He had been making eledtric discharges, in 
collaboration with Prof. Ebert, by a special apparatus for 
producing eledtric oscillations of high frequency. This 
apparatus, in the modified form given to it by Ebert 
{Wiedemann's Annalen, liii., p. 144, 1894), stands on the 
table before you. It is an apparatus ol the same class as 
that described here some years ago by Oliver Lodge, for 
producing Hertzian waves. An oscillating spark is pro- 
duced between two polished balls set between two con- 
densers, A and B, each made of plates of sheet zinc 

* A Ledlure delivered at the Royal Institution of Great Britain, 
Friday, May 8, 1896. 



(Fig. 7) a few m.m. apart. Their external circuit is 
however, led into the primary of a small indudtion-coil, 
the secondary of which goes to a third condenser, c. 
When sparks from the Apps coil are sent to the spark-gap, 
the oscillations of the two primary condensers set up 
secondary oscillations in the third condenser, to which a 




Fig. 7. 

vacuum tube can be conneded. If, now, by adjusting the 
distances between the plates of condensers, we tune the 
primary and secondary circuits together, the eledric oscil- 
lations that result will persist much longer than if the 
circuits are not so tuned. Though each oscillation may 




Fig. 8. 



last less than the loo-millionth of a second, there will be 
at each spark some 20,000 or 30,000 oscillations before 
they have died out. Wiedemann and Ebert have found 
that these persistent oscillations are specially adapted to 




Fig. 9. 

excite luminescence. To illustrate the point I seledl here 
an old Geissler tube with a comparatively poor vacuum. 
When stimulated by ordinary sparks diredlly from the 
Apps coil through the platinum ele^rodea at its ends, it 



CRBMICAL NbWS, I 

March 12, 1897. f 



Electric Shadows and Luminescence, 



123 



f^- 







'^M 






Fig. 10. 



shows the usual features of Geissler tubes: there is a 
luminous column extending through the central bulb with 
stratifications along its length, while around the kathode 
is the usual violet glow. The glass shows no fluorescence. 
I now charge the conne<5lions, uniting the wires from 
Eber's apparatus, not to the terminal eledrodes of the 
tube, but to two patches of tin-foil stuck upon the outside 
of the central bulb. Under these conditions the eledtric 
oscillations illuminate the central bulb with a glow quite 
different from that previously seen. Beneath each patch 
of foil you can discern the bluish kathode discharge, and 
the glass now shines with charaiSleristic apple-green 
fluorescence. By moving one plate of one of the con- 
densers in or out, I alter the conditions of resonance in 



the circuit, and when the tuning is best the fluorescence 
is at its brightest. Now Wiedemann observed (Zeitschr. 
fur Elektrochemie, July, 1895, p. 159) that the light so 
generated is capable of exercising a photographic aftion, 
and of other effeds, but is incapable either of passing 
through a thin plate of fluor-spar or of being defleded by 
a magnet. These rays differed, therefore, both from 
ultra-violet light and from kathode rays ; hence Wiede- 
mann pronounced then to consist of a new species which 
he named " Entladungsstrahlen," or discharge-rays. It 
is again a matter for research to determine whether 
Wiedemann's rays are the same as Lenard's, or as Ront- 
gen's rays. Wiedemann's coadjutor Ebert went on with 
the research, and produced on this principle a little 













Table I. 






Change 














Cause 


Cause 








Nature 


Restore 


Capable 


Capable 




Cause 


Penetrate 


photo- 


combina- 


Defleaed 


Discharge 


Affeft 


of 


thermo- 


of 


of 


Kind of rays. 


lumi- 


alumi- 


graphic 


tion of H 


by 


elearifl- 


spark 


eleftric 


lumi- 


being 


refrac- 




nescence 


. nium. 


aftion. 


and CI. 


magnet. 


cation. 


length. 


discharge. 


nescence. 


polarised. 


tion, &c 


Ultraviolet light 


Yes 


— 


Yes 


Yes 


No 


If - 


Yes 


— 


Yes 


Yes 


Yes 


Infra-red light .. 


No 


No 


— 


No 


No 


No 


— 


— 


No 


Yes 


Yes 


Hertzian waves . 


No 


No 


— 


No 


No 


Charge 
vio- 


Yes 


— 


No 


Yes 


Yes 


Kathode rays . . 


Yes 


If thin 


Yes 





Yes • 








__ 




















lently 












Lenard rays 


Yes 


Yes 


Yes 


— 


Partly 


Yes 


Yes 


Yee 


— 


— 


— 


Wiedemann rays 


Yes 


Yes 


Yes 


— 


No 


— 


— 


— 


Yes 


— 


— 


Rontgen rays . . 


Yes 


Yes 


Yes 


— 


No 


Yes 


Yes 


Yes 


Yes 


No 


No 


Becquerel rays.. 


— 


Yes 


Yes 


— 


No 


Yes 


— 


— 


— 


Yes 


— 


Eledric effluve.. 


Yes 


No 


Yes 


Yes 


? 


— 


— 


— 


Yes 


No 


No 



124 



Electric Shadows and Luminescence. 



< CRBklCAL NbwS, 

( March iz, 1897. 



" luminescence lamp " having two external rings of foil 
as electrodes ; and within the vacuum bulb a small pastille 
of phosphorescent stuff, which, when excited by the oscilla- 
tions of the tuned circuits, glows with a small bright light. 
Ebert claims that its efficiency is many times greater than 
that of the ordinary glow lamp. 

Returning now to Rontgen's researches, we will take a 
glance at the kind of tube (Fig. 8) which he was em- 
ploying when he made his discovery of the X-rays. Its 
general resemblance to previous tubes* is self-evident. 
The anode was a piece of aluminium tube through which 
passed the glass-covered kathode wire, with a small flat 
aluminium plate on its extremity. From this flat plate 
kathode rays shot forward against the bulging end of the 
tube, and, without any aluminium window rays which 
were capable of exciting fluorescence, found their way 
through the glass walls. Lenard had so boxed up his 
tube with brass cap and metal case, that if anything in 
the way of rays struggled through the glass walls of his 
tube he might not notice it. Possibly he never looked 
for it. Rontgen made the fortunate observation that when 
his tube was closely covered with opaque black card it 
still could cause fluorescence on a screen covered with 
platino-cyanide of barium on which shadows were cast. 
From seeing the shadows thus to securing their imprint 
permanently on a photographic plate was but s small 
step, and the discovery that they could pass freely through 
a sheet of the metal aluminium was the natural result of 
an inquiry as to the transparency of different materials. 
Aluminium is to these rays much more transparent than 
ordinary glass. No lens can focus them, nor mirror 
refle(5t them, and, unlike the kathode rays within the tube, 
they are not defledled by the magnet. 

The criterion which we have at present as to whether 
any rays from any other source are or are not the same as 
the X-rays is that they shall be able to fulfil the following 
fourfold test : — They must be capable of exciting lumi- 
nescence ; they must be capable of impressing an image 
on a photographic plate ; they must be capable of passing 
through aluminium ; and they must be incapable of being 
defledted by a magnet. In addition they must — so far as 
present evidence goes — be incapable of being either re- 
fradted or polarised. Any rays that will fulfil these tests 
must for the present be considered identical with X-rays. 

Now it has been suggested that the X-rays are the 
same as ultra-violet light. This is certainly not so, for 
ultra-violet light, as known to us by the researches of 
Stokes, Tyndall, Becquerel, and Cornu, will not go through 
aluminium and is not defledled by a magnet, though it 
will excite luminescence and take photographs. Further- 
more, ultra-violet light can be refra(5ted and polarised. 

It has also been suggested that the X-rays are merely 
invisible heat-rays. But this is certainly untrue also, 
because although Abney has succeeded in taking photo- 
graphs by heat-rays, they will not go through aluminium, 
are not deiletfted by the magnet, and instead of exciting 
phosphorescence they destroy it, as Goethe found out 
nearly a hundred years ago. 

Neither are they Hertzian waves of longer period than 
the heat waves. 

So far as is at present known there is no other way of 
producing the X-rays than that of employing the highly 
exhausted vacuum tube. They are not found in the light 
of ordinary eledlric sparks in air. They are not discover- 
able amongst the rays emitted by ordinary Geissler tubes 
with a low exhaustion. They are not found in sunlight or 
any artificial light. The arc light, though it yields rays 
that will give photographic shadows through a thin pine- 
wood board, yields no rays that will pass through 
aluminium. The only other rays that seem to come 
within reasonable possibility of being X rays are the 
Lenard rays, some of which are probably identical with 
Rontgen's ; the Wiedemann rays, which are, so far as yet 

» 

* It is, in faA, identical with the form described by Hertz in 1883 
See Wiedemann's Annalen, xix.. p. 810. 



investigated, entirely similar; and the Becquerel rays, to 
which some allusion will presently be made. It will, 
however, be convenient here to present a synoptic table 
(see Table I.) of the various kinds of rays and their 
respedtive physical properties. 

One other physical property of the X-rays has been dis- 
covered since the publication of Rontgen's research. It 
was discovered simultaneously in Cambridge (by Prof. 
J. J. Thomson), in Paris, in Bologna, and in St. Peters- 
burg, that these X-rays will cause the diseledlrification of 
an eledtrified body, no matter whether it is positively or 
negatively charged.* That ultra-violet light can dis- 
eledtrify bodies that have been negatively charged was 
previously known from the researches of Hertz, and of 
Elster and Geitel. This fresh discovery that X-rays will 
also discharge a positive eledtrification sets up a new 
physical test. Let me show you a simple piece of appa- 
ratus which I have found very convenient for the purpose 
of demonstrating this discovery. It is an aluminium-leaf 
eledtroscope (Fig. g) entirely shielded from all external 
eleiSlrostatic influences by being enclosed in transparent 
metallic gauze. It is so well shielded that even when the 
cap is removed it cannot be charged in the ordinary in- 
dudtive way, but must be eledtrified by diredi conduAion. 
The aluminium-leaves hang at the side of a fixed central 
plate as in Exner's electroscope. The containing vessel 
is of thin Bohemian glass. On exciting the instrument 
positively from a rod of rubbed glass, or negatively from 
a rod of rubbed celluloid, the leaves diverge. In either 
case, as soon as the X-rays are caused to shine upon the 
instrument, the leaves fall. 

It occurred to me that by the aid of this property of 
diseledlrification it might be possible to produce eledtric 
shadows without having resort to any photography. You 
are aware that if the surface or any part of the surface 
of a body is eledlrified, the fadl that it is eledtrified can be 
ascertained by dusting over it mixed powders of red-lead 
and sulphur (or red-lead and lycopodium). With the aid 
of Mr. Miles Walker, who has worked with me all through 
this matter, I have succeeded in producing, on this plan, 
well defined shadows which will now be demonstrated to 
you. A clean sheet of ebonite, freed from all traces of 
previous eledtrification by being passed through a spirit 
flame, is laid on a properly prepared metal table. On it 
stands a small tray of thin aluminium, supported on four 
insulating legs. In this tray is placed the objedt whose 
shadow is to be cast, — for example, a pair of scissors or 
an objedl cut out in sheet lead. Over this again is placed 
a leaden cover with an opening above the tray, the leaden 
cover being designed to cut off eledlrostatic influences 
which might interfere. The tray is then eledtrified by a 
small influence machine, and while it is so eledtrified 
X-rays are sent downwards from a Crookes tube placed 
above. They pass down through the aluminium tray and 
carry its eledtrification to the ebonite sheet, which there- 
fore becomes eledtrified all over except in the parts which 
are shielded by the scissors or other metallic objedt. The 
sheet of ebonite is then removed from the leaden enclosure, 
the aluminium tray lifted off, and the mixed powders are 
dusted over, adhering to the surface of the ebonite and 
revealing the otherwise invisible eledtric shadow. Fig. 10 
is a shadow taken in this way. It is but right to mention 
that Prof. Righi, of Bologna, has independently obtained 
eledtric dust shadows in a very similar way since these 
experiments of mine were begun. 

(To be continued). 



Annmoniacal Silver Chlorides.— R. Jary.— In the 
case of ammoniacal chlorides the dissociation in a space 
occupied by water ensues in the same manner as in a 
\!iCu\im.—Comptes Rendus, cxxiv.. No. 6. 

♦ It is of great interest to note that this identical property had 
been observed by Lenard a year previously as an effedl of his rays. 
He found they would discharge an eledtroscope enclosed in a metal 
chamber, with an aluminium sheet in front, whether positively 
or negatively charged, aad at a distance of 30 centimetres from 
bis tube. 



C<IBMICAL NbWS, 

March 12, 1897. 



} Volumetric Determinatton of Molybdenum and Vanadium, 125 



VOLUMETRIC DETERMINATION 

OF MOLYBDENUM AND VANADIUM.* 

By CARL FRIEDHEIM. 

(Concluded from p. gi). 

Hence they {i.e., Gooch and Fairbanks) recommend to 
effei5t the whole operation in a current of carbon dioxide 
free from atmospheric air, for which, instead of the simple 
and convenient Bunsen apparatus, a more complicated 
distillatory apparatus is requisite, which, on account of 
its greater capacity, must give greater errors except we 
work with carbon dioxide. That better results cannot be 
obtained has been already mentioned. 

A further reason which Gooch and Fairbanks advance 
for the necessity of their proposed alteration of my 
method cannot hold good. They consider it necessary 
that the solution to be decomposed during the operation 
should be evaporated down from a given initial volume 
to a fixed final volume, interrupting the process as soon 
as the latter is reached. They were led to this modus 
operandi " because it is not sufficient to indicate that the 
ebullition must be interrupted when the liquid has taken 
a clear green colour, and when a vapour of the colour of 
iodine ceases to pass over, for the green colour of the 
solution is formed very slowly, and we (Gooch and Fair- 
banks) were able to show iodine in the residue long after 
the green colour had been perfectly developed." 

The latter phenomenon certainly takes place, but has 
nothing whatever to do with the redudlion of the molj'b- 
denum teroxide, but must be referred to the fadl that if 
the contents of the flask are brought in contad with the 
air the hydriodic acid is at once oxidised. The longer 
such a solution is left in contadl with carbon disulphide 
with access of air the more intensely it is coloured, which 
does not ensue if air is excluded. 

The appearance of the green tinge and the disappear- 
ance of the iodine colouration shows sharply the end of 
the readtion, as it is manifest from results already pub- 
lished, even for substances whose proportion of molyb- 
denum is unknown, and gives a more trustworthy basis 
than boiling down the solution to a certain volume, which 
is suitable only for the weights used by Gooch and Fair- 
banks, and cannot be at once transferred to substances 
whose proportion of molybdenum is unknown. 

In the same connexion we must notice another proposal 
made by the same authors. It is well known that vana- 
dium pentoxide can be quantitatively reduced to tetroxide 
by potassium bromide and hydrochloric acid, and that an 
excellent volumetric method for determining vanadium 
can be secured (Holverscheidt's method) by receiving the 
liberated halogen in potassium iodide, and titrating the 
iodine set at liberty. In concert with Euler I have 
showed that on boiling vanadium pentoxide with potas- 
sium iodide and hydrochloric acid, the redudlion can like- 
wise be carried almost quantitatively as far as vanadium 
tetroxide, whilst vanadium teroxide is formed quantita- 
tively on the addition of syrupy phosphoric acid. Of 
course, we have not utilised this result for a volumetric 
investigation of pure vanadates, for which there was no 
need, since the potassium bromide method is simpler, 
more convenient, and more trustworthy. Ph. E. Browning 
(Zeit. Anorg. Chemie) now proposes to modify this method 
of reduction so that the redudion of the vanadates is 
effedled under certain conditions in open vessels with 
potassium iodate and sulphuric acid ; the solution, after 
the iodine has been expelled by boiling is neutralised 
with alkaline hydroxide mixed with tartaric acid and 
bicarbonate, and the vanadium tetroxide existing in 
solution is determined with a standard solution of iodine, 
titrating back with arsenious acid. 

As an advantage over the convenient method of distil- 
lation, it is alleged that the complicated distillatory 



* Berichte d. D. Chem. Qestll. 



apparatus is superfluous. To this it may be replied that 
the manipulation of the compendious Bunsen apparatus 
18 the most convenient conceivable, that the supercession 
of a smooth titration with thiosulphate by titration with 
two standard solutions, in one case with a blue liquid, 
does not mean any progress, and that, finally, in 
Browning's method, the determination of the bases (e.g., 
lead and barium) in the residue of the distillation is ren- 
dered impossible and much more difificult. 

Exadly the same objedtions must be urged against the 
modification of my method for the determination of 
molybdenum as proposed by Gooch and Fairbanks, which 
consists in decomposing the molybdate in an open method 
and titrating it on Browning's principle. 

In a subsequent memoir (Zeit. Anorg. Chemie) A. v • 
banks proposes to determine the phosphorus in the yellow 
ammonium phospho-molybdate indiredly, the molybde- 
num in the compound being ascertained according to the 
Gooch-Fairbanks-Browning method. The authors here 
overlook to mention that I have already recommended 
the volumetric determination of the molybdenum in 
phospho-molybdates, and the method which I have 
described, and that I connedled with it Hundeshagen's 
method for titrating the total method by alkali hydroxide, 
therefore determining the phosphoric acid as difference. 
This method is, however, of interest only for the general 
examination of the so-called white phospho-molybdates; 
for the determination of the phosphorus in the yellow 
compound the gravimetric method of Hundeshagen- 
Pemberton is far simpler and more convenient than that 
proposed by Fairbanks. 



PROCEEDINGS OF SOCIETIES. 

CHEMICAL SOCIETY. 
Ordinary Meeting, January 21st, 1897. 

Mr. A. G.Vernon Harcourt, President, in the Chair. 

Messrs. Charles A. Hill, Arthur Marshall, and William 
H. Sodeau were formally admitted Fellows of the Society. 

Certificates were read for the first time in favour of 
Messrs. William Arbuckle, 34, Moore Street, Cadogan 
Square, S.W. ; Masumi Chikashige, B.Sc, Kumamoto, 
Japan ; Alfred Foster Cholerton, Lyndum House, Lincoln 
Street, Leicester ; Clarence Hamilton Creasey, 78, Bagge- 
holme Road, Lincoln; James Crowther, B.Sc, West 
Field, Lightcliffe, Halifax ; William Alfred Davis, 108, 
Gordon Road, Peckham, S.E., Ernest Goulding, 18, 
Mercer's Road, Holloway, N; Charles Heppenstall, 
Ferrybank, Arklow, Co. Wicklow ; Harold Johnson, 5. 
Boulevard Clovis, Bruxelles ; William Robert Lang, B.Sc., 
5, Crown Gardens, Glasgow ; Barker North, 3, Manor 
Terrace, Felixstowe ; Herbert Spindler Pullar, Rosebank, 
Perth, N.B ; William Ralston, B.Sc, 337, Cathcart Road, 
Lrlasgow;John Stewart Remington, Dromore, Milverton, 
Leamington ; Leonard Sumner, B Sc, Butt Hill, Prest- 
wich, near Manchester; Andrew Turnbull, Ph.D., Dal- 
dowie, Broomhouse, near Glasgow. 

The certificates of the following candidates, recom- 
mended by the Council, under Bye-law I., par. 3, were also 

Thomas Hannibal Aquino, Gadag, Dharwar Distrid, 
India; Alfred Rutter, Broken Hill, N.S.W. ; Rustomii 
Navroji Unwalla, Bhaunagar, Kathiawar, India. 

The following is the text of the letter which has been 
received from Professor Stanislao Cannizzaro, acknow- 
ledging the address presented to him by the Society on 
the occasion of his jubilee. 

To the Council and Fellows of the Chemical Society 

of London. 
Gentlemen,— I beg to offer to your Society the report 
of the celebration of my seventieth birthday, togethti 



I2( 



A ctton of Diastase on Starch. 



CbbmicalNbws, 

March 12, 18Q7. 



with the volume containing some of my writings which 
were reprinted on that occasion, and a copy in bronze of 
the gold medal which was presented to me. 

At the same time, I beg to convey to my colleagues 
the expression of my heartfelt gratitude for their very 
flattering address, which I have received with the greatest 
satisfadiion. 

The Chemical Society won my devotion, when, in 1862, 
they added my name to the restridled roll of their foreign 
members ; and again in 1872 when they honoured me by 
intrusting to me the delivery of the Faraday Ledture. 

A further proof of their high consideration is now 
offered to me in this address, in which I find my labours 
for Science appreciated and valued in so very high a 
degree by authority so competent : I feel I am indebted 
for this favourable estimate of my merits to the extreme 
kindness which my English colleagues have always 
shown to me, and for which I now desire to express my 
profound gratitude. 

Great is the pleasure which this fresh manifestation of 
their affedlionate esteem has afforded me, thus assuring 
me that their estimate of me has in no way lessened. 
Your ever true and affe(5lionate colleague, 

Stanislao Cannizzaro. 

December, 1896. 

Of the following papers those marked * were read : — 

•i. " Observations on the Properties of some Highly 
Purified Substances." By W. A. Shenstone. 

1. The author has compared the behaviour of oxygen 
under the influence of the silent discharge of ele(5tricity 
when saturated with water vapour, and when carefully 
dried. The results show that, contrary to the statement 
of previous investigators, oxygen is most freely convened 
into ozone when wet, and that well dried oxygen yields 
only a very minute percentage of ozone. The_ results 
obtained also shows that the ozone in ozonised oxygen 
is far more stable in the presence of water vapour than 
in its absence. That is to say, the change by which 
ozone is converted into oxygen is very greatly retarded 
by the presence of moisture. 

2. Chlorine prepared by the eleftrolyis of silver chloride, 
and also carefully purified bromine and iodine, have been 
dried by very thorough treatment with prepared phos- 
phoric oxide, and then presented to the aiftion of mercury 
prepared for the purpose by several di8tin(ft methods and 
thoroughly dried. In every case the metal and the 
halogen interadled instantly and rapidly. 

3. Highly purified chlorine, when submitted to the 
silent discharge of ele(5tricity, does not undergo condensa- 
tion. 

4. The abnormal expansion of chlorine which has been 
described by several observers appears to depend upon 
the presence of impurities in the chlorine. 

Incidentally, a new vacuum tap and other novel appa- 
ratus are described in this paper. 
Discussion. 

The President, Mr. H. B. Baker, and Professor 
TiLDEN expressed their admiration of the skill and 
resource which Mr. Shenstone had brought to bear in 
investigating a difficult problem. 

Dr. Thorpe stated that he had witnessed Dr. Budde's 
experiments at Bonn, which were conduded with great 
care, and he had watched the expansion of chlorine under 
the influence of the violet and ultra-violet rays. The 
chlorine had been prepared by the oxidation of hydro- 
chloric acid, and was believed to be pure. Some sub- 
sequent observers had confirmed Dr. Budde's results, but 
others had failed to do so — as was now the case with 
Mr. Shenstone, whose painstaking enquiry, he hoped, 
might be the means of finally settling the question. 

Dr. Thorne stated that he had observed on a large 
scale the instability of ozone when in contact with an 
alkali. 

Mr. Shenstone, in reply, stated that he did not doubt 
the correctness of Dr. Budde's observations with chlorine > 



prepared and purified as he had described. He con 
sidered, however, that such chlorine could not be regarded 
as highly purified, and that moisture was almost certainly 
present. 

*2. '• The Action of Diastase on Starch." By Arthur 
R. Ling and Julian L. Baker. 

The authors show that maltose when heated with 
Fehling's solution, under the conditions prescribed by 
Wein, reduces rojg grms. of copper per grm. of sugar. 
The table of Wein, therefore, gives results which are 4-5 
per cent too low, a result also arrived at by Brown, 
Morris, and Millar. 

They have examined in detail the produdts of the 
limited adlion of diastase on starch at 70°, and have 
separated maltose and the following unfermentable sub- 
stances, which were purified to such an extent as to free 
them from all extraneous matter. 

Maltodextrin o, CagHezOsi, identical with Brown and 
Morris's maltodextrin, but having the properties 
[o]d = i8o : R = 32-8i. 

Maltodextrin p, C24H4202I, identical with Prior's 
" achroodextrin III.," and having the properties 
[o]d = 17i6 and R = 43. 

A substance, C12H22O11, isomeric with maltose, and 
obtained from the unfermentable residue of that particular 
fradion previously called isomaltose by Lintner. It had 
the constants [a]D = i56 and R = 62'5, and may consist 
of the simple" dextrin," C12H20O10+H2O, the existence 
of which the authors' previous work foreshadowed. 
Inasmuch as it gave a small amount of crystalline 
osazone, it perhaps contained maltose. 

When the three substances above named are treated 
with an excess of diastase at 60° for a few hours, the 
approximate reducing powers of the products are R=90 ; 
Qi'S ; 94i respedively. 

There are now ample data to conclude that starch, 
when hydrolysed by diastase, is converted into a series 
of maltodextrins of gradually decreasing molecular 
weight and optical rotatory power, and of increasing 
reducing power. These appear to have the optical and 
reducing properties of mixtures of the original starch and 
maltose. 

Discussion. 

Dr. G. H. Morris regretted that Messrs. Ling and 
Baker had given no particulars of the substances they 
described beyond the constants [ajo and R. He had 
therefore no means of judging whether the substances 
agreed with the maltodextrin described by Mr. H. T. 
Brown and himself, nor was it possible to follow the 
authors' line of work. The constants given for malto- 
dextrin o agreed fairly with the law of definite relation as 
formulated by Mr. Brown and himself; but the malto- 
dextrin /3 (Prior's achroodextrin III.) did not, and the 
purity of this substance is therefore doubtful. He wished 
to learn more about the unfermentable residue of isomal- 
tose, which the authors appeared to regard as one of the 
end-produdls of the action of diastase on starch. He did 
not think it necessary to enunciate a new theory of 
starch conversion whilst there was still so much dispute 
as to fads. 

Mr. Ling, in reply to Mr. Chapman, said he saw no 
reason for assuming the presence of a " stable" dextrin 
among the produds of starch hydrolysis ; ultimately 
maltose was the sole produd. In reply to Dr. Morris, he 
said that much more information would be found in the 
paper than it had been possible to give an account of in 
the brief time at his disposal. It would be seen that the 
formulae of the maltodextrins could not be calculated 
from the percentages of apparent maltose which they 
yielded. 

•3. " The Solution Density and Cuptic-Reducing Power 
of Dextrose, Lavulose, and Invert-Sugar.^^ By Horace 
T, Browne, F.R.S., G. Harris Morris, Ph.D., and J. 
H. Millar. 

The authors have extended the methods deacribed in 



Chbuical News, i 
March 12, 1897. ] 



Derivatives of Maclurin. 



127 



their previous paper {Proc, 1896, xii., 241) to the exami- 
nation of the solution density and cupric-redudtion of 
dextrose, laevulose, and invert-sugar. They find that the 
solution densities of the two former differ considerably 
with the same concentration of the solution, but that the 
volume occupied in solution by a unit of weight of each 
is less at lower than at higher concentrations, conse- 
quently the divisor to be applied to the specific gravity 
decreases with the concentration. The solution density 
of invert-sugar was calculated from those of dextrose and 
laevulose, and the results so obtained were confirmed at 
vaiious points by direift experiments. 

They also find that the cupric-reducing powers of the 
three sugars, when determined under their standard con- 
ditions, are, for dextrose, /c=ii7 to 105 ; for lasvulose, 
ic=i07'5 to loi ; and for invert sugar, ic = iii to 103. 
The higher numbers are obtained when a small amount 
of cuprous oxide is precipitated, and the lower when 
redudtion is carried nearly to the maximum. When the 
experimental numbers are expressed in the form of a 
curve, it is found that at the one end, taking the cupric- 
redudlion of dextrose at 100, laevulose is represented by 
91-3, and invert-sugar by 94*2 ; at the other end of the 
curve the ratio is 100, 94'6, and 975 ; whilst at an inter- 
mediate point, which corresponds to the amount of cuprous 
oxide usually reduced, the relation is, dextrose 100, 
laevulose 92-3, and invert-sugar 9615. 

4. "Derivatives 0/ Maclurin.^^ Part II. By A. G. 
Perkin. 

From maclurin which yields a pentabenzoyl derivative 
(Konig and Kostanechi, Ber., 1894, xxvii., 1996), a pent- 
acetyl compound has not yet been obtained, for by 
acetylisation in the ordinary way only sticky produdls 
result, and when excess of sodium acetate is employed 
(Ciamician and Silber, Ber., 1894, xxvii., 1628), there is 
formed a peculiar substance having the composition of 
pentaceiyl maclurin less i molecule of water. Judging 
from the stability of maclurin-azo-benzene, 

C,3H806(N2-C6H5)2. 
described in a previous communication (Bedford and 
Perkin, Trans., 1895, Ixvii., 933), when compared with 
that of maclurin itself, it appeared probable that this on 
acetylisation might behave normally, which was found 
to be the case. 

Triacetylmaclurin-azobenzene, 

Ci3H506(C2H30)3(N2-C6H5)2, 
orange-yellow needles, m.p. 240 — 243°, is insoluble in 
cold alkaline solutions, but decomposed by them on 
boiling. Suspended in acetic acid and treated with sul- 
phuric acid, a quantitative yield of maclurin-azobenzene 
is produced. Phloroglucin-azobene similarly yields a 
monacetyl derivative, C6H303(C2H30)iN2C6H5)2, orange- 
red needles, m.p. 222 — 223°, also quantitatively decom- 
posed by sulphuric acid into the azo-compound. These 
substances furnished no higher acetyl derivatives, two 
hydroxyls present in the original molecules of maclurin 
and phloroglucinol having assumed in their diazobenzene 
compounds the ketonic condition. This method is being 
applied for the estimation of hydroxyl groups in certain 
analogous substances, particularly catechin and cyano- 
maclurin, which combine readily with diazobenzene, but 
do not give normal produdts on acetylisation by the usual 
method. 

Mention is made of a second produdi closely resembling 
luteolin trimethyl ether, and formed at the same time, 
during the methylation of luteolin. This, though isolated 
many months since, was not mentioned at the time, be- 
lieving that the work then published was sufficient to 
establish priority for the further study of this readtion. 
The author wishes to reserve this to himself for further 
examination. 

5. '• Halogen-substituted Acidic Thiocarbimides and 
their Derivatives ; a Contribution to the Chemistry of the 
Thiohydantdins:^ By AuausTUS Edward Dixon, M.D. 



Continuing his previous work on the acidylthio- 
carbimides IJ^rans., 1895, Ixvii., 1040; 1896, Ixix., 855; 
ibid , 1593, &c.), the author endeavoured to prepare 
halogen substitution derivatives of certain members of the 
faity acid class, in the hope that, by combination with 
organic bases, glycolylthioureas would be obtained of 
known sirudlure, whose relations to the thiohydantoins 
produced by other methods would serve to decide the con- 
stitution of the latter. 

The derivatives in question were obtained by heating a 
mixture of sand and lead thiocyanate with the ohalogen- 
ised acid chloride (or bromide), dissolved in anhydrous 
toluene; as a rule, the yield amounted to only about 
60 per cent of the theoretical. On bringing the produdks 
into contadt with primary or (secondary) amines, inter- 
adtion occurred spontaneously, with elimination of the 
halogen, and formation of the corresponding substituted 
thiohydantoin, for instance — 

CH 'S 

CH2Cl-CO-NCS-f-ToNH2=HCl-h | ^ \c:NTo. 

co-nh/ 

By prolonged boiling with hydrochloric acid, the latter 
compound is hydrolysed, ammonia being formed, together 
with a substance (melting at 119 — 120°) identical with the 
" orihotolylthiocarbimidoglycolide" obtained by Voltzkow 
{Ber., 1880, xiii., 1580) from EtOH,ToNCS and 
CH2CICOOH. Since the nitrogenised organic group, 
introduced by the base in the formation of the thiohydan- 
toin, does not form an integral portion of its ring, whilst, 
on the other hand, the nitrogen withdrawn by hydrolysis 
holds no organic radicle in combination, it follows that 
the ring must exchange its NH for oxygen, thereby be- 
coming — 

CHj'Sv 
I >C:NTo; 

coo/ 

thus, by an entirely different method, the formula is cor- 
roborated, which Evers assigns to the corresponding 
phenyl derivative (Ber., 1888, xxi., 975). From ortho- 
tolylthiourea and ethylic chloracetate, a thiohydantoin 
was obtained, agreeing in properties with that produced 
from the thiocarbimide ; on hydrolysis, it afforded the 
same glycolide, m. p. 119 — 120°. 

On the other hand, thiourea, when treated with a sub- 
stituted chloracetamide (e.g., chloracetanilide) yielded 
(P. Meyer, Ber., 1877, x., 1965) thiohydantoin, together 
with a substitution derivative; the phenylthiohydantoin 
so obtained was apparently identical with that produced 
from phenylthiourea and ethylic chloracetate. The 
essential interadion he explained substantially as fol- 
lows : — 

CHjCl HSv CH2*S V 

I -J- >C:NH = HCl-{- I >C:NH, 

CO-NHPh NH2/ CO-NPh/ 

and the fadt that ammonia and phenylthiocarbimido- 
glycolide were formed on hydrolysis, appeared to agree 
satisfadlorily with the above view of its constitution, as 
well as to fix that of the glycolide, — 

CH2-S V CHj-S V 

>C:NH-|-H20 = NH3-t- | >C0. 

CONPh/ CO-NPh/ 

It would seem, however, from Meyer's paper, that the 
particular phenylthiohydantoin obtained from chlor- 
acetanilide was not used in preparing the related phenyl- 
thiocarbimidoglycolide ; it was conceivable, therefore, 
that the former might, though melting at the same tem- 
perature, be really isomeric with that produced by the 
other methods. This could be ascertained by examining 
the produdls of hydrolysis, for the withdrawal from the 
ring of its nitrogenised group would afford aniline, to- 
gether with " thiocarbimidoglycolide," — 
CHj'Sv 

I >C:NH; 

CO'O / 



128 



Halogen-Substituted A cidic Thiocarbimides* 



I CtlBMieAL NBltrS) 

I March 12, 1897. 



whilst, even if the phenyl group should be retained, and 
ammonia formed instead, the produ(5t — 

I >co 

CO-NPh/ 

would still be an isomeride of the true phenyl thio- 
carbimidoglycolide, — 

I >C:NPh. 

CO-0 / 

But, on experiment, the produdls of hydrolysis, and hence 
the thiohydantoin itself, were found to be identical with 
those obtained in other ways. Finally, the compound 
was decomposed by carbon disulphide at 180°, phenyl- 
thiocarbimide being obtained, together with rhodanic 
acid, but not a trace of thiocyanic acid ; and hence the 
interadlion follows the course — 



CHjS V CH/S 

I >C:NPh + CS2= I 

conh/ CO-NH 



/ 



PhNCS. 



The author therefore regards the known monosubstituted 
thiohydantoins in which the radicle is attached to nitro- 
gen, as constituted on the type— 
CHa-S 



CONH 



C:NR 



CONHPh NHa'' 



and suggests that the formation of the phenylic member 
from thiourea and chloracetanilide may be due to a 
secondary a^ion, for thiohydantoin is also produced, 
together with aniline, — 

CHaCl HS V 

+ NC:NH = PhNH2+ 

CHa'S V 

+ 1 >C:NH + HC1; 

conh/ 

and from these, by mutual interaction, ammonia and 
phenylthiohydantoin might result. Ammonia was, in 
fadt, expelled, when aniline and thiohydantoin were 
heated together with alcohol ; and a substance produced, 
which appeared, judging from its melting-point, to be its 
phenylic derivative, but the quantity obtained was insuf- 
ficient for analysis. 

The following compounds are described : — 

Orthotolylthiohydantohi, — 

CHa'S V 

I >C:NC7H7. 

CO-NH/ 

From chloracetylthiocarbimide and orthotoluidine ; 

white prisms, melting at 144 — 145° (corr.). When boiled 
with baryta-water it yields thioglycolic acid ; by boiling, 
dilute hydrochloric acid, it is slowly decomposed into 
ammonia and •' orthotolylthiocarbimidoglycolide," — 

CHa'Sv 

I >C:NC7H7. 

CO-0 / 
The same thiohydantoin is produced from orthotolyl- 
thiourea and ethylic monochloracetate ; its hydrochloride 
melts at 212-5—213-5° (uncorr.). 
Methylphenylthiohydanto'in, — 

CHa■S^. 

I \C-N(CH3)C6H5. 
CO-N ^ 

From the thiocarbimide and methylaniline ; flattened 

needles, melting at 129—130° (corr.), and decomposed by 
boiling with caustic alkali or baryta-water, into ammonia, 
methylaniline, and thioglycollic acid. It is also ob- 
tained by heating aa-methylphenylthiourea, in alcohol, 
with ethylic monochloracetate ; the hydrochloride melts 
at I93-I94"'' 



Benzylphenylthiohydanto'in, — 

CHa'Sv 

>CNPh-CHa-Ph. 



CO 



-N^ 



— From benzylaniline ; it melts at 118—119°, and is de- 
composed by prolonged boiling with hydrochloric acid, 
into benzylaniline, and a substance melting at about 
123—124°, probably " thiocarbimidoglycolide." 

Allylphenylthiohydantoin. — From allylphenylthiocarb- 
amide and monochloracetamide an oil was obtained ; it 
appears to be a mixture of the two forms — 



CHa-S V CHaS . 

I >C:NPh and | >:NA1I. 



CO-NAIK CONPh' 

a Bromopropionylthiocarbimide, CHj-CHBr-CO NCS, 
when treated with orthotoluidine, affords wf<A_y/o>'</iofo/y/- 
thiohydanto'in, — 

CH3'CH-S \^ 

I >C:NC7H7. 

CO-NH/ 

Crystalline powder, melting at 72—73°, and decomposed 
by boiling dilute alkali, with formation of o-thioladic acid, 
CH3-CH(SH)-C02H. 
Dithethylphenylthiohydanto'in, — 

CH3-CHa-SK 

I >C-N(CH3)PH. 

co-n/^ 

—From the above thiocarbimide and methylaniline ; 
vitreous plates, melting at 129—130°. 

a-BromobutyrylthiocarbimideyCH^'CHz C^^t'CO-UCS' 
by combination with aniline, yielded ethylphenylthio' 
hydantoin, — 

CH3-CHa*CH-S v 

I >C:NC6H5. 

CO-NH/ 

White needles, m. p. 148 — 149° (corr.). 

Ethylorthotolylthiohydantotn. — A sandy white powder, 
melting at 95—96°, to a turbid liquid, clearing at 98°; 
the hydrochloride forms white needles, m. p. 224 — 225° 
(corr.). When boiled with alkali, then acidified and 
mixed with ferric chloride, followed by ammonia, a 
purplish colouration is produced, due, probably, to the 
presence of o-thiobutyric acid. 

For greater convenience and precision in naming 
" thiohydantoins " of the above types, and the corre- 
sponding derivatives of — 

.NH-CHa 
CS< I , 

^NH-CO 

together with the related " thiohydantoic " acids, the 
author proposes a modification of the nomenclature at 
present employed. 

6. •' The Amyl (Secondary butyUmethyl) Derivatives of 
Glyceric, Diacetylglyceric, and Dibenzoylglyceric Acids, 
Active and Inactive.'' By Percy Frankland, Ph.D., 
B.Sc, F.R.S., and Thomas Slater Price, B.Sc. 

The authors describe the preparation and properties of 
amyl (laevo-a(5tive) glycerate (dextro-adive), amyl (in- 
adive) glycerate (dextro - a<5tive), amyl (laevo-adtive) 
glycerate (inadive), as well as of the corresponding 
diacetyl and dibenzoylglycerates. The Interest attaching 
to these bodies depends, firstly, on those compounds with 
the inadtive amyl and adive acid radicle filling gaps in 
the series of adive glycerates, diacetylglycerates, and 
dibenzoylglycerates already prepared, and described by 
one of the authors. The position of the maximum rota- 
tion in these series becomes thus more precisely localised. 
Secondly, the influence of one asymmetric carbon atom 
on another in the same molecule can be ascertained, and 
the principle of the superposition of the optical effeds of 
the asymmetric carbon atoms is put to the test and found 



CRBIllCAL MBWSi 1 

March I2, 1897. ' 



Wide Dissemination of some of the Rarer Elements. 



129 



to hold good. Thus the authors show how the optical 
properties of the eight possible adtive amylglycerates can 
be calculated from a knowledge of the optical properties 
of two particular ones, and similarly in the case of the 
eight adtive amyl diacetylglycerates, and the eight active 
amyl dibenzoylglycerates. 

In the series of the dibenzoylglycerates, of which now 
the methyl, ethyl, propyl, and amyl terms are known, the 
rotation diminishes from the methyl to the amyl com- 
pound, and there is every probability that in this series 
the rotation will be found to pass through a minimum. 

The influence of temperature on the rotation of all the 
compounds described has been also investigated, with the 
result that, as before, the rotation of the glycerates was 
found to be but little sensitive to temperature, the rota- 
tion of the diacetylglycerates much more sensitive, and 
that of the dibenzoylglycerates still more sensitive to 
temperature. Again, as before, it was found that the 
negative rotation of the diacetylglycerates increased, 
whilst the positive rotation of the dibenzoylglycerates 
diminished with rise of temperature. It was, however, 
further found that the compounds in which the amyl 
alone was adtive, viz., amyl (laevo-active) glycerate 
(inadive), amyl (Isevo-aftive) diacetylglycerate (inadlive), 
and amyl (Isevo-aftive) dibenzoylglycerate (inadlive), had 
their rotation pradtically unaffedled by temperature, the 
sensitiveness to temperature being thus confined to the 
rotation dependent on the asymmetric carbon atom 
belonging to the glyceric acid part of the molecule. 

7. " The Refraction Constants of Crystallised Salts.' 
By Alfred E. Tutton. 

This communication is in reply to certain criticisms of 
Pope [Trans., 1896, Ixix., 1530) concerning the author's 
work on the refradlion constants of the sulphates and 
double sulphates containing potassium, rubidium, and 
csesium {Trans., 1896, Ixix., 502). It is first shown that 
the claim of Pope to originality, in showing that the mole- 
cular refradions of solid salts are the sums of the atomic 
or equivalent refradlions of the components, is unfounded, 
and that the whole of the conclusions published in the 
author's memoir, with regard to this subject, in connec- 
tion with the entire twenty-two double sulphates investi- 
gated, were based upon the assumption of this rule. The 
second point is with regard to the criticism that the mean 
molecular refradlions of the salts given were not the mean 
of the three values corresponding to all three refradlive 
indices of the biaxial crystals in each case, but the mean 
of the two extreme values ; and with regard to the re- 
calculated results presented by Pope taking the inter- 
mediate value into account, which Pope appears to show 
exhibit far greater accordance than the author's values. 
The author points out that the course pursued was taken 
after careful consideration, with full knowledge of the 
problem, and for the sufficient reason that the whole of 
the salts in question were so extremely feebly doubly re- 
fradtive, and the extreme values consequently so close 
together, that he judged that the difference between the 
results of the two processes would be within the range of 
experimental error. He then shows that grave errors 
occur in Pope's re-calculations ; there are numerous 
errors in Table III., two of them being whole numbers, 
one of which amounts to a fifth of the total value, and 
Table IV., is entirely wrong in consequence. When the 
errors are corredted, the latter table, in which the two 
whole-number errors also appear, assumes quite a different 
aspedt, the results of the two modes of calculation become 
nearly identical, the differences between them being then 
well within the range of the experimental error, and amply 
justify the author's course. The author finally shows 
that the two cases, rubidium sulphate and caesium sul- 
phate, quoted by Pope as adverse to the author's state- 
ment that " the matter in a crystal has, for refradlion 
purposes, the same average effeA as the same matter 
uncrystallised," lead to diametrically opposite conclu- 
sions ; and, moreover, that such conclusions are of no 



value, as the differences in question between the values 
for solution and for the crystallised condition are well 
within the range of experimental error. 

8. " The Re/raction Constants of Crystallint Salts.'' 
A Corredlion. By William Jackson Pope. 

The author regrets to find, notwithstanding that the 
numbers used in his paper {Trans., 1896, Ixix., 1530) were 
several times checked, an error of a unit in two numbers 
in Table III. which vitiates the first line of Table IV. 
{loc. cit., p. 1537) ; the first, third, seventh, and ninth 
numbers in the line in question should be 5*11, 5*26, I4'5t 
and 15*00, and in the fourth column of Table III. the 
numbers 4*25 and 13*51 should each be increased by 
unity. The comparison made in the six lines following 
Table IV. is consequently unjustifiable. 

The error, although to be regretted, in no way affeiAs 
the general argument, but, if left uncorredted, tells unfairly 
against the method of calculation used by Tutton. 

9. " On the Wide Dissemination of some of the Rarer 
Elements and the Mode of their Association in Common 
Ores and Minerals." By W. N. Hartley, F.R.S., and 
HUQH Ramaqe. 

By means of spedlrographic analysis the authors have 
examined about 170 specimens of ores and minerals, 
comprising oxides, carbonates, and sulphides. Half a 
grm. of each substance, finely powdered, was heated in 
the oxyhydrogen flame. The following elements and 
their compounds yield spedlra under these conditions 
which are easily observed. 

(a) In very small quantity — 

Na, Ca, Pb, Ni, K, Se, Bi, Cu, Ba, Cr, Kb, Ga, Mn, 
Ag, In, Fe, Cs, Tl, Co. 

(6) In small quantity — 

Li, Au, Cd, Sb, and Sn. 

(c) In such quantity as to indicate that the substance 
is a principal constituent of the mineral — 

Be, B, Di, Te, Rh ?, Mg, Al, S, Pd ?, Zn, Ce, Se, Ru ?. 

Some of the metallic elements in the list (c) under 
special conditions yield oxyhydrogen flame spedlra, which 
are easily observed even in small quantity. Other ele- 
ments than the above have not been sought for in this 
research. 

In almost every case the locality from which the speci- 
mens of ores and minerals came is recorded, and the re- 
sults of the spedtrographic analysis have been tabulated. 
Several novel and interesting fadts are disclosed, which 
may be stated very briefly as follows : — 

Clay Iron-stones and Black-band Ores. — Fifty-one 
specimens examined. All contain sodium, potassium, 
copper, calcium, and manganese ; 47 contain silver; 32, 
lead; 21, gallium; 13, nickel; 12, chromium; i, stron- 
tium ; and i, thallium. Probably all contain rubidium, 
but it is difficult to recognise owing to the multitude of 
iron lines. Three specimens undoubtedly contain it. 

Brown Hcematites. — Six specimens examined. All con- 
tain sodium, potassium, copper, calcium, and manganese ; 
5 contain silver; 5, lead ; and 5, nickel; 3, chromium ; 
2, gallium ; 2, thallium ; and i, indium. Probably all 
contain rubidium ; in one it is undoubtedly present. 

Limonites. — Five specimens examined. All contain 
sodium, potassium, silver, manganese, and apparently 
rubidium; 4 contain calcium; 4, lead; 3, copper; 3, 
nickel; i, gallium; i, thallium ; and i, chromium. 

Red Hcematites. — Eighteen specimens examined. All 
contain sodium and potassium; 17 contain copper ; 14, 
manganese; 13, silver; 12, lead ; 12, calcium; 3 contain 
gallium ; 3, indium ; 3, nickel ; 2, chromium ; i, rubidium ; 
and I, thallium. 

Magnetites. — Seven specimens examined. All contain 
sodium, potassium, copper, silver, calcium, gallium, lead, 
and manganese. Four appear to contain rubidium ; 2, 
Bickel ; and i contains indium. 

Siderities. — Five specimens examined. All contain 
sodium, potassium, copper, silver, calcium, indium, and 



130 



The late Georges VtUe. 



I Cheu:cal News, 
i Mareh 12. 13^7, 



manganese; 3 contain lead; i contains rubidium; i, 
gallium; i, cobalt; i, nickel; and i, bismuth. 

Aluminous Minerals, such as Bauxites. — Seventeen 
specimens. All contain sodium, potassium, copper, cal- 
cium, and iron ; 16 contain gallium; 15, chromium ; 13, 
nickel ; 12, manganese ; g, silver ; 3, lead ; and 2, 
rubidium. 

Manganese Ores and Minerals. — Eleven specimens ex- 
amiiicd. All contain sodium, potassium, copper, calcium, 
and iron ; 10 contain silver ; 5, rubidium, and 5, nickel; 
4, gallium ; 4, lead ; and 4, strontium ; 2, barium ; i, 
indium; and i, cobalt. 

Blendes —Fourteen specimens examined. All contain 
sodium, copper, silver, and iron ; 13, potassium ; 12, gal- 
lium; 12, lead; 10, silver; 10, manganese; g, indium ; 
7, cadmium; 4, thallium; 2, nickel; and i, chromium. 
The zinc was observed in only 8 specimens, the spedtrum 
being hidden by other lines. 

Nickel and Cobalt Ores. — Nine specimens examined. 
All contain sodium, potassium, copper, calcium, iron, and 
nickel; 6 contain cobalt; 6, lead; 4, chromium; 3, silver; 
I, barium; and i, strontium. 

Tin Ores. — Five specimens examined. All contain so- I 
dium, indium, and iron ; 4 contain potassium ; 3, copper ; 
3, calcium ; 3, lead ; 2, silver; and 2, manganese. 

Galenas. — Eight specimens. All contain sodium, 
potassium, copper, silver, and iron ; 4 contain manganese ; 
and 3, calcium. 

Pyrites.— Th'iTieen specimens. All contain sodium, 
potassium, copper, silver, calcium, and iron; 11 contain 
lead; 10, manganese ; 5, indium; 5, thallium ; 5, nickel ; 
and I, gallium. 

Out of 168 ores and minerals examined, gallium occurs 
in 68 ; indium in 30 ; and thallium in 17. Rubidium oc- 
curs probably in 70, but unquestionably in 13. All the 
carbonates of iron and all the tin ores, without exception, 
contain indium. With one single exception, all the 
bauxites contain gallium. 

Silver, copper, calcium, potassium, and sodium are very 
widely disseminated through all ores and minerals. 

The authors draw dedudions as to the formation of 
beds and lodes of ore from the following fadls, which they 
claim to have established :— First, that certain groups of 
ores and minerals are pervaded by small quantities of the 
same metals as common impurities. Secondly, the rare 
metals, more particularly rubidium, gallium, indium, and 
thallium, are associated with the same groups of minerals, 
and also with allied groups. 

It is easy to trace the association of similarly consti- 
tuted compounds to their connexion with elements 
related to each other, as determined by the periodic 
system of classification. These compounds have certain 
properties in common, distindlive of the groups of elements 
and compounds to which they belong ; hence in a given 
course of chemical changes, similar compounds are 
formed and thrown together by precipitation or otherwise. 
All the minerals mentioned have undoubtedly had an 
aqueous origin. 

The presence of the alkali metals in all the specimens, 
but in variable proportions, has a special significance. 

In the analysis of many different precipitates, obtained 
both in neutral and even strongly acid solutions, the 
alkali metals have been found in combination with the 
precipitated substance. It has long been known that 
manganese, aluminium, and iron in the state of 
hydroxides, combine with more or less of the alkalis, 
but in a great measure such combinations have been dis- 
regarded. 

Anniversary Meeting. 

The Anniversary Meeting will be held on Wednesday, 
March 31st, at 3 o'clock in the afternoon. 
Anniversary Dinner. 

It has been arranged that the Fellows of the Society 
and their friends shall dine together at the Criterion 
Restaurant on Wednesday, March 3i8t, at 6.30 for 7 p.m. 



OBITUARY. 



THE LATE GEORGES VILLE. 

It is our very painful duty to put on record the death of 
our valued friend Georges Ville, who closed his most useful 
and honourable career on February 22nd. The deceased 
held the Chair of Vegetable Physiology in the Museum 
of the Jardin des Plantes. His life has been essentially 
devoted to a pradical study of the vital conditions of 
plants, and especially of our food-plants. 

Professor Ville pointed out the necessity of keeping 
cultivated lands adequately supplied with those constitu- 
ents of plant-food which are most readily exhausted by 
the crops. As such, in addition to phosphoric acid, 
potassium salt, and nitrogen, he laid great weight on 
lime in the form of gypsum. This recommendation, we 
need scarcely say, though borne out by his experiments, 
is not ratified by British pradice. To keep cattle for the 
produAion of manure — as is done by too many farmers in 
this country — he humorously compared to the condud of 
a supposed iron manufadurer who should plant and keep 
up forests to supply his work with fuel. He shows that 
all the elements of plant-food can be obtained at less cost 
from mineral sources. But it is a gross misunderstanding 
to say that Prof. Ville denounced the use of animal 
manures. 

He introduced in France the method of trial-plots of 
arable land, thus making the plant analyse the soil for 
itself. The process which he names sideration is simply 
ploughing in crops which are of no value in themselves, 
but which serve to enrich the soil especially by fixing 
atmospheric nitrogen in states suitable for the nourish- 
ment of succeeding crops. 

His published works, some of which have been trans- 
lated into English, are of great but unequal value. His 
ledtures on agriculture, delivered in Belgium as well as in 
France, cannot fail to rouse up the agricultural mind, 
though they carry ideas which in England would be quite 
out of place. But he has done an incalculable service to 
France, and to the civilised world in general, by exposing 
the worn-out fallacy that organic matter by passing 
through the bodies of horses or of oxen acquires some 
novel and mysterious virtue which it had not before. 

Ville's chref works are : — " Artificial Manures " 
(Longmans and Co.), and "The Perplexed Farmer, how 
is he to meet Alien Competition ? " (Longmans and Co., 
i8gi). 



NOTICES OF BOOKS. 



London 



Directory of Paper Makers, January, i8gy, 

Marchant, Singer, and Co. 
The paper industry does not meet with an amount of 
attention from the outside public at all commensurate 
with its importance. 

The work before us confines itself 8tri(5lly to the con- 
ventional funiflions of a diredlory without entering at all 
upon the prospers, the difficulties, and possible dangers 
of the trade. The manufadlure of filter-papers occupies 
the attention of eight firms, but we fear we must say that 
none of these takes a standing equal to that of Munktell 
and Co., of Sweden, and Schleicher and Schiill, of 
Germany. 

A circumstance which we much regret is that the 
trade is so scantily developed in Ireland. There the air 
is less polluted with smoke than in most parts of England 
and even of Scotland ; the water supply is more abundant 
in quantity, and we think we may say superior in purity 
to that on our side of St. George's Channel. Ireland has, 
in short, the greatest natural facilities for the develop- 
ment of the paper manufafture. 



Chkuical Nbws, 
March 12, 1897. 



Chemical Notices from Foreign Sources, 



13' 



CORRESPONDENCE. 

RELATION BETWEEN ROTATION 

AND REDUCING POWERS OF HYDROLYSED 

STARCH SOLUTIONS. 

To the Editor of the Chemical News. 
SiR.^I have not yet read the full paper of Browne, 
Morris, and Millar, a notice of which appears in the 
Chemical News (Ixxv., p. 42). 

The fadt that a constant relation exists between cupric 
reducing and rotatory powers in hydrolysed starch solu- 
tions was pointed out by me, in a paper read before the 
A.A.A.S. at the Boston meeting, in 1880, and published 
in full in the Proceedings for that year, and in the 
yournal of the American Chemical Society (vol. ii,, 1880, 
pp. 395 — 402). There is also an abstraft of my paper in 
the Berichte der Deutschen Chemischen Gesellscha/t 
(xiv., 1584). 

From the results of my investigations, it would be 
only a logical conclusion to infer that similar relations 
exist among hydrolytic starch produdls in general. In 
the materials examined by me, the produdls of hydrolysis 
were chiefly dextrose and dextrine. In the researches 
made by the authors above mentioned, maltose and dex- 
trine were the chief hydrolytic produfts. 

In my paper the data of the examination of a large 
number of samples of commercial starch glucoses are 
found, with formulae for calculating the percentage of 
reducing sugars for varying specific gravities. The cal- 
culated reducing powers obtained by these formulae were 
found to agree remarkably well with the adtual reducing 
data secured with Fehling solution. With the improved 
modern optical and chemical methods it is quite certain 
that a formula could be construdted for the hydrolytic 
produdls of starch obtained with sulphuric acid, which 
would give diredtiy, from the optical observation of the 
solutions, pradically corre(^ figures for reducing powers. 
— I am, &c., 

H. W. Wiley, Chief of Division. 

United States Department of Agriculture, 

Division of Chemistry, Washington, D.C., 
February 24, 1897. 



CHEMICAL 



NOTICES FROM 
SOURCES. 



FOKtlCiN 



Note.— All degrees of temperature are Centigrade unless otherwise 
expressed. 

Comptes Rendus Hebdomadaires des Seances, del'Academie 
des Sciences, Vol. cxxiv,, No. 6, February 8, 1897. 

M. Leidier, of Marseille, addressed to the Academy a 
memoir on an automatic lightning rod for telegraphic and 
telephonic lines. 

New Researches on the Determination of Pyro- 
phoric Acid. — M. Berthelot and G. Andre. — Fadls to 
serve towards the " History of Metaphosphoric Acid," 
by M. Berthelot and G. Andre. 

Redutftion of Nitrates in Arable Soil. — P. P. Dehe- 
rain. — These three papers will be inserted in full. 

Certain Coloured Rea(5^ions. — E. Pineura. — These 
colourations are obtained with /3-naphthol-sulphuric acid 
prepared by dissolving 0-02 grm. of j3-naphthol in i c.c. 
ofsulphuricacidofsp.gr. i'83; we add from 10 to 15 
drops of this reagent to about 0*5 grm. of the substance 
to be charadterised ; if the latter is in solution it is gently 
evaporated to dryness. Tartaric acid gives at first a blue 
colour, which, if we continue to heat, gradually passes to 
a very decided green tint ; if, when the matter is cold, 
we add 15 to 20 times its volume of water we obtain a 



permanent yellowish red. Citric acid gives an intense 
blue, which does not turn green with prolonged applica- 
tion of heat. The addition of 15 to 20 times its volume 
of water gives a colourless solution, or one very fainly 
yellowish. A small quantity of tartaric acid mixed with 
the citric acid brings up the green tint which pure citric 
acid never produces; 10 to 12 percent of tartaric acid 
then produces a dark greenish blue. Pure malic acid 
gives at once a yellowish green colour, which becomes 
bright yellow on prolonging the heat. The addition of 
water turns the colour to a bright orange. These readlions 
are charadteristic and easy to observe ; it is merely neces- 
sary to heat carefully, and to withdraw the capsule from 
the fire as soon as any colour is observed. If it ceases to 
increase in intensity, we heat afresh if requisite. Other 
organic substances produce similar colours, but less defi- 
nite and charadteristic. /3-naphthoI sulphuric acid also 
serves to distinguish the alkaline nitrites ; 10 drops of this 
reagent, added to 0*05 grm. sodium nitrite, dissolved in a 
few drops of water, give rise to a very intense redness, 
which is not altered on the addition of water. Alkaline 
nitrates may be distinguished in an analogous manner by 
means of a solution of o'lo grm. resorcin in i c.c. of sul- 
phuric acid at 176. The adlion of this reagent upon 
0*05 grm. potassium or sodium nitrate determines the 
appearance of a red-brown, which soon becomes a very 
intense violet, and which passes to orange on the addition 
of water. 

New Method of Preparing the Primary Amines. — 
Marcel Delepine. — It becomes easy to have a pure pri- 
mary amine, if we can combine the corresponding mineral 
ether with hexamethylamine. 

Sanitation of the Match Trade. — M. Magitot. — 
The author's conclusions are: — i. The sanitation of the 
manufadture of matches with white phosphorus is a pro- 
blem simple and easy of solution. 2. The method of 
sanitation consists of two orders of means based on two 
fadiorsof injury, which are (a) phosphorism, (6) necrosis. 
3. To phosphorism we oppose the ventilation of the work 
by artificial means, powerful enough to withdraw the 
poisonous emanations from the workers. To necrosis we 
oppose the principle of seledlion ; that of recruitment and 
maintenance from the hands of persons entirely free 
from any injury of the mouth or the jaws which might 
furnish an opening for the chemical mischief. 4. The 
problem of sanitation is entirely comprised in the two 
terms — ventilation and seledlion. 

Determination of Potassium Bitartrate in Winss. 
— Henri Gautier. — This paper will be inserted in full. 

Indigenous Essence of Basil (Ocymum basilicum). 
— MM. Dupont and Guerlain. — The produdt which ac 
companies linalol in oil of basil is estragol (para-methoxy- 
allylbenzene). 

Argon and Nitrogen in the Blood. — P. Regnard and 
Th. Schlcesing. — The authors were obliged to operate on 
about 10 litres of blood. The blood, on leaving the veins, 
could not be allowed to come in contadt with the air for 
a single instant. Whilst adhering to fadls positively ob- 
served, the authors conclude that argon exists in solution 
in the blood. 

No. 7, February 15, 1897. 
The Age of Copper in Chaldea.— M. Berthelot. — 
Already inserted. 

A Safety Receiver adapted for containing Liquefied 
Gases. — J. Fournier. — This paper requires the accom- 
panying figures. 

Influence of the X-Rays on the Striking Distance 
of the Eledlric Spark.— M. Guggenheimer.— The author 
has succeeded in establishing that : — i. At equal dis- 
tances and at equal potential differences the augmentation 
of the striking distance of the passive spark depends on 
the intensity of the X-rays encountering the micrometer. 
2. At an equal diifersnce of potential (by the micro< 



132 



Meetings /or the Week, 



r Crshical nbws, 
1 March i2, 1897. 



meter) and at an equal intensity of the X-rays the 
augmentation of the striking distance of the passive 
spark depends on the distance of the micrometer from the 
emissive wall of the tube. 3. The interposition of a 
fluorescent screen of barium platinocyanide, of a plate of 
glass, or of quartz does not appreciably change the 
radiation. 

False Equilibria of Hydrogen Selenide. — H. Pela- 
ron. — A mathematical paper v/ith a diagram, not suitable 
for insertion. 

Adtion of Cuprous Oxide upon Solutions of Silver 
Nitrate. — Paul Sabatier. — Not susceptible of useful 
abstradtion. 

On certain Derivatives of Salicylic Aldehyd. — 
Paul Rivals. — A thermo-chemical paper. The heat of 
molecular combustion is = 15897 cal. at constant 
volumes and 15903 cal. at a constant pressure. 



NOTES AND QUERIES. 

♦»♦ Our Notes and Queries column was opened for the purpose of 
giving and obtaining information likely to be of use to our readers 
generally. We cannot undertake to let this column be the means 
of transmitting merely private information, or such trade notices 
as should legitimately come in the advertisement columns. 

Dental Alloy*.— Are there any books on the alloys used in den- 
tistry ? If 80, who are the publishers ?— Jack. 

MEETINGS FOR THE WEEK. 

Monday, 15th.— Society of Arts, 8. (Cantor Leftures). "Alloys," 

by Prof. W. Chandler Roberts Austen, F.R.S. 
Tuesday, 16th.— Royal Institution, 3. " Animal Eleftricity," by 
Prof. A. D. Waller, F.R.S. 

Society of Arts, 8. •' The Progress of the British 

Colonies of Australasia during the Sixty Years of 
Hei Majesty's Reign," by James Bonwick. 
WxDNBBDAV, i^th.— Society of Arts, 8. " Music in England at the 

Queen's Accession," by J. Spencer Curwen. 
Thursdav, iSth.— Chemical, 8. " On the Atomic W«ight of Car- 
bon," by Alexander Scott, M.A., D.Sc. " On 
a New Series of Miacosulphates of the Vitriol 
Group," by Alexander Scott, M.A., D.Sc. 
" The Aftion of Alkyl Haloids on Aldoximes 
and Ketoximes," by Wyndham R. Dunstan, 
F.R.S., and Ernest Goulding. 

Royal Institution, 3. " Greek History and Extant 

Monuments," by Prof. Percy Gardner, F.S.A. 
Friday, 19th.— Royal Institution, 9. "Greek and Latin Palao- 

graphy," by Sir Edward Maunde Thompson. 
Saturday, 20th.— Royal Institution, 3. " Eleftricity and Electrical 
Vibrations," by Right Hon. Lord Rayleigh, M.A., 
F.R.S. 

ACETONE — Answering all requirements. 

.A.OHD J^CIETIO— Purest and sweet. 

BODB-A-dC-Cryst. and powder. 

__ OZETDESiIO— Cryst. made in earthenware. 
(3. /X T.T. Tn— From best Chinese galls, pure. 

SJLIjIG'Z'XjIO— By Kolbe's process. 

rj|i_^3<q-2<3"XO— For Pharmacy and the Arts. 

LIQUID CHLORINE 

(Compressed in steel cylinders). 

FORMALIN (W" CH2O)— Antiseptic and Preservative. 

POTASS. PERMANGANATE— Cryst., large and small, 

SULPHOCYANIDE OF AMMONIUM. 

BARIUM. 

THORIUM, ZIRCONIUM, and CERIUM SALTS. 

T A RTA R E M ET I C-Cryst. and Powder. 

PUMICE. TRIPOLI AND METAL POWDERS. 

ALL CHEMICALS FOR ANALYSIS AND THE ARTS. 

Wholesale Agents— 

A. & Mr ZIMMERMANN, 

9 & 10, ST. MARY-AT-HILL, LONDON, E.G. 



An Associate of the Institute of Chemistry* 

^*- who has had four years' experience with Consultant Analyst 
and four years at Works, desires engagement. Food and Agricultural 
work specialities. Unexceptional references. — Address, H. I., 271 
Wellington Square, London, S.W. 

A nalytical Chemist, A.I.C., who has had expe- 

■^ •^ rience in well-known Laboratory and Cement Works, seeks 
employment in Works or Laboratory. — Address, " Works,'' Chemi- 
cal News Office, 6 & 7, Creed Lane, Ludgate Hill, London, E.C. 

Analytical Chemist (Ph.D.) seeks Engage- 

^*- ment ; Belgian (26); studied in Germany and Switzerland; 
three and a half years' experience with Agricultural Laboratory ; 
now engaged at Aniline Colour manufadtories. Thorough knowledge 
of English, French, German, and Dutch. — Address, "A.B.K.," care of 
Street and Co., 30, Cornhill, E.C. 

A ssistant wanted, at the end of March, in a 

^ ^ London Analytical Laboratory. Hours, 10 to 5 ; Sat., 10 to I. 
Annual holiday, 14 days. Applicants must be experienced in the 
quantitative analysis of water, food, drugs, and commercial substances 
generally. F.LC. or A.LC. preferred. Salary, paid monthly, jf 100 
to £125 a year, according to qualifications. — Apply to A.Z., Chemical 
News Office, 6 & 7, Creed Lane, Ludgate Hill, London, E.C. 

\A7"orks' Chemist, A.I.C, late with large 

' • London manufacturers, well up in Plant and Building Con- 
stru(5tion, experience in management of men, and in conduSion of 
Technical Research work, good Commercial Analyst, seeks Appoint- 
ment. Moderate Salary.— Address, " Plant," Chemical News Office, 
6 &7, Creed Lane, Ludgate Hill, London, E.C. 

'^XT'anted, in London Smelting Works, an 

* * Assistant Chemist. Must be well up in Leady and Cuprous 
material. — Write C.N. gzg, Deacon's Advertising Offices, Leadenhall 
Street, London, E.C. 



\7"oung Chemist wanted as Assistant in large 

-■■ Manure Works. — Apply, by letter only, to Mr. Vincent 
Edwards, F.LC, West End Laboratory, 55, Weymouth Street, W. 

pOR SALE.— Complete set of "Journal of 

•*■ the Chemical Society," from 1848 — 1896. 70 vols., bound in 
half calf; good condition Enquiries and offers to M.Sc, Chemical 
News Office, 6 & 7, Creed Lane, Ludgate Hill, London, E.C. 

OOARD OF WORKS FOR THE POPLAR 

*-* DISTRICT. 

TO CHEMICAL MANUFACTURERS AND OTHERS. 

NOTICE IS HEREBY GIVEN, 
That the Board will meet at the Board Room, 117, High Street, 
Poplar, on Tuesday, the i6th day of March inst., at 6.30 o'clock in 
the evening precisely, to receive 

TENDERS 
for the Supply of 

DISINFECTANTS 
for one year, ending Lady Day, i8g8, as follows, viz., — 

CARBOLISED PEAT POWDER, 15 PER CENT OF 

CARBOLIC, AT PER TON. 

PERMANGANATE OF POTASH, AT PER Lb. 

BLACK CARBOLIC ACID, 33 PER CENT OF CARBOLIC. 

CHLORO-NAPTHOLEUM, IN BULK, 25 PER CENT OF 

CARBOLIC. 

BURNETT'S DRAIN TESTS, AT PER GROSS. 

KEMP'S DRAIN TESTS, AT PER GROSS. 

The Board do not bind themselves to accept the lowest or any 

Tender. 

ContraAors will be required to pay Trade Union rates of wages, 
and to covenant not to sub-let any portion of the ContraA. Com- 
pliance with these conditions will be rigidly enforced under a penalty 
of the sum of £5 for each breach. 

Contradtors will be required to furnish securities to the satisfaction 
of the Board, and to enter into bond with them for the due perform- 
ance of Contraft, and pay down the sum of £2 immediately upon 
acceptance of the Tender, towards the expenses of the contra(5t and 
bond. 

Tenders, upon the forms for that purpose, are to be delivered, in 
separate covers, duly marked and sealed, before Two o'clock in the 
afternoon of the i6th day of March, after which time no Tender will 
be received. 

Further particulars and Forms of Tender can be had at the Office 
of the Surveyor, any day to the 15th day of March, between 9 a.m. 
and 4 p m. 

WM. HENRY FARNFIELD, 
Board Offices, Clerk to the Board. 

117, High Street, Poplar, E., 
6th March, 1897. 



Cbbmioal Nbws, I 
March 19, 1897. J 



Estimatton of Zinc Oxide, 



133 



THE CHEMICAL NEWS 



Vol. LXXVm No. 1947. 



A NOTE ON THE ESTIMATION OF ZINC 
OXIDE. 

By B. ASTON, B.Sc. (Lond.), and L. NEWTON, 
University College, London. 

Fbesenius States that zinc oxide, when mixed with sul- 
phur, and heated gradually to redness in a current of 
hydrogen gas, is quantitatively transformed into zinc sul- 
phide. 

We attempted in this way to determine the purity of 
zinc oxide prepared in the following manner from pure 
zinc, and have met with an anomaly which, we think, 
deserves to be placed on record. A preliminary analysis of 
the zinc was first made, by dissolving a weighed quantity 
in nitric acid, evaporating to dryness, igniting, and then 
weighing the zinc oxide obtained. 

i'io6 grms. of zinc gave 1*38075 grms. of zinc oxide. 
Percentage of zinc in the ZnO — Found, 80*29 ; Calculated, 
80*24. 

50 grms. of zinc, thus shown to be almost pure, were 
dissolved in pure nitric acid, and the solution evaporated 
to dryness. The residue was taken up with water, and 
the solution filtered. To the filtrate a few drops of ammo- 
nium sulphide were added, the liquid was allowed to stand 
for some hours with repeated shaking, and then filtered. 

The filtrate was evaporated to dryness on a water-bath, 
then dried in an air-bath at 150° C, and finally ignited, first 
in the blowpipe, and then for three hours in a muffle 
furnace. 

Two weighed specimens of oxide thus prepared were 
mixed with sulphur and gradually heated to redness in a 
current of hydrogen gas. 

After cooling down in the gas the crucibles were 
weighed. 

This process was repeated in the one case sixteen, in 
the other twenty-two times, but in neither did the quan- 
tity of zinc sulphide exceed 96 per cent of the theoretical, 
though it had increased generally by a small amount at 
each weighing. 

These results might conceivably be due to impurities 
in the zinc oxide used, andTwe therefore tried another 
method of estimation, viz., as sulphate, in order to see 
whether the same result would be obtained. 

A weighed quantity of the oxide was dissolved in dilute 
sulphuric acid in a weighed platinum crucible and evapor- 
ated to dryness ; the greater part of the acid was driven 
off by heating in an asbestos oven to about 340° C. 

The crucible was placed in a sulphur bath for about two 
hours, then removed and weighed. It was replaced in the 
bath for an equal period of time, and then re-weighed 
(Baubigny, Comptes Rendus, vol. xcvii., p. 854). The 
weight had not changed, and the result of the experiment 
was that — 

0*5742 grm. of ZnO gave 1*14065 grms. of ZnS04; 

hence the percentage of zinc in the zinc oxide was 80*19 
instead of 80*24, the theoretical quantity. 

Our zinc oxide, therefore, was pure, and, so it would 
seem, that the change from oxide prepared from zinc 
nitrate, to sulphide by heating with sulphur in a current 
of hydrogen, cannot be made the basis of a quantitative 
method. 

At this point it may be advisable to give some of the 
numbers experimentally obtained. 



(z). 0*3555 g"ii* of zinc oxide gave— 

ist weighing 0*3735 grm. ZnS. 

0*3905 



6th 
loth 
nth 



0*3985 
0-3985 



At this stage ZnS and sulphur were ground together in 
an agate mortar, so as to make sure of an intimate 
mixture. 

14th weighing 0*4065 grm. ZnS. 

i6th , 0*4070 „ „ 

At this point the quantity of ZnS obtained was 95*59 
per cent of the theoretical. 

(2). In this case the zinc oxide and sulphur were in 
each case ground together in an agate mortar, and then 
introduced into the crucible. 

0*4685 grm. of zinc oxide gave — 

isi weighing 0*5055 grm. ZnS. 

"th „ 05275 „ „ 

i3tn •• 05280 „ „ 

15th M 0*53275 „ „ 

i6tn .1 o'53a5 „ » 

aand „ 05374 „ „ 

At this point the experiment was arbitrarily stopped. 
The quantity of zinc sulphide obtained was 95*88 per cent 
of the theoretical. The compound formed appears in 
each case to correspond roughly to a formula 3ZnS.2ZnO. 
Two points may be noted about these numbers : — 

1. After the first heating with sulphur, the weight of 
sulphide produced is more than 85 per cent of the theo- 
retical, being in the first case 87*7 per cent and in the 
second 90*10 per cent ; any further increase is only by 
very small quantities, and cannot be due to impurities in 
the sulphur, which left no residue on ignition. 

2. Two weighings may give exadlly the same number ; 
that is to say, a constant point is reached, and yet on re- 
peating the process an increase is obtained. Thus it is 
impossible to find a point at which the change from oxide 
to sulphide definitely stops. 

It was thought advisable to see whether, under the 
same circumstances, zinc oxide prepared from compounds 
other than the nitrate would be quantitatively changed 
into sulphide. 

Experiments were therefore tried with — 

(i) Zinc oxide prepared from zinc sulphide by ignition. 

(2) „ „ „ carbonate „ 

(3) II II II sulphate „ 

(i). The zinc sulphide used was prepared by dissolving 
some of our pure zinc oxide in acetic acid, and passing 
into the solution a current of sulphuretted hydrogen gas. 

The precipitate was coUei^ed, washed, and then dried 
in a current of hydrogen gas. 

That this sulphide was pure is shown by the following 
analyses : — 

(a) 0*1582 grm. ZnS gave on ignition 0*1322 grm. ZnO. 

(b) 0*11075 „ „ 0*0925 „ 

Percentage of Zn Percentage of Zn in ZaS 
found. calculated by theory. 



(a) 
(b) 



67*052 



67*010 
67*010 



0*11585 grm. of zinc oxide thus prepared was heated 
with sulphur in the usual manner, and gave 0*13860 grm. 
ZnS. 

Percentage of Zn Percentage of Zn in ZnO 

found. calculated by theory. 

80*16 80*24 

(2). Zinc Oxide prepared from Zinc Carbonate. 
Some zinc oxide was dissolved in acetic acid, and pre- 
cipitated with pure ammonium carbonate solution. 



134 



Electric Shadows and Luminescence, 



I Cbbmical Nbws, 
March ig, 1897. 



The precipitate was colledled, washed with boiling 
water, and then ignited until its weight remained constant. 
0'2245 grm. of zinc oxide thus prepared was mixed with 
sulphur and treated in the usual manner, giving 02685 
grm. of zinc sulphide. 



Percentage of Za 
found, 

8o'i4 



Percentage of Za in ZnO 
by theory. 

8o'24 



(3). Zinc Oxide prepared from Zinc Sulphate. 
The zinc oxide used in this case was prepared by 
igniting to a constant weight the sulphate previously ob- 
tained in the estimation of zinc oxide as sulphate. 

o"i40 grm. of zinc oxide gave o'i68 grm. of zinc sul- 
phide. 

Percentage of Za Percentage of Zn in ZnO 

found. calculated. 

80*41 80*24 

It must be pointed out that in this case the final point 
was only reached after three ignitions with sulphur. But 
after the first ignition the quantity of zinc sulphide 
formed was already 98*4 per cent, and therefore the case 
is hardly comparable to that of the oxide prepared from 
the nitrate. 

Thus, zinc oxide prepared by ignition of the nitrate is 
not quantitatively transformed into sulphide by heating 
with sulphur in a current of hydrogen gas, as are speci- 
mens of oxide prepared in other ways. 

University College, London, 
March, 1897. 



THE DETERMINATION OF TITANIC ACID. 
By J. JAS. MORGAN. 

In determining titanic acid in iron ores by the usual 
methods, part of it is found with the insoluble residue 
and part in the acid solution. Arnold, in his " Steel 
Works Analysis," describes a method based upon the 
principle that, in the presence of excess of phosphate of 
iron, titanic acid forms an insoluble phospho-titanate of 
iron, and is found with the insoluble residue, and, in the 
absence of suf&cient phosphate of iron to fix the titanium 
in this form, brings about the desideratum by the addition 
of ammonium phosphate. The method on the whole is 
very satisfadtory, the only drawback being the method of 
precipitating the titanium, which is effected by boiling 
the largely diluted solution (measuring 1000 c.c.) until the 
volume is reduced to 250 c.c. This occupies considerable 
time, while the precipitate not unfrequently adheres so 
tenaciously to the beaker as to render the complete 
removal a very difficult matter. The writer, therefore, 
prefers Blair's method of precipitation, and carries out 
an estimation as follows (a combination of Arnold's and 
Blair's methods) : — 

To the weighed portion of the dry ore add i grm. of 
ammonium phosphate dissolved in a little water, and 
effedt solution by digesting with hydrochloric acid, and, 
when solution is complete, evaporate to dryness and well 
bake. Dissolve the dry mass in hydrochloric acid, dilute, 
coUedt the insoluble residue (containing the whole of the 
titanic acid as phospho-titanate of iron) on a filter-paper, 
and wash with hot dilute hydrochloric acid and cold water 
until free from iron salts. Dry the filter-paper and contents, 
ignite the contents in a platinum crucible, and mix with 
about ten times its weight of potassium carbonate. Fuse, 
extradt the fusion in a little hot water, filter off the inso- 
luble, and well but carefully wash with hot water. Then 
dry filter and contents, place in a platinum crucible, 
ignite, mix with about 6 grms. of acid potassium sulphate, 
and fuse at a low red heat for half an hour. Extradt the 
cold fusion in 10 c.c. of hydrochloric acid and 30 c.c. of 



sulphurous acid, filter, and wash with hot water. Dilute 
the filtrate, add 20 grms. of sodium acetate dissolved in 
water, then one-sixth the volume of acetic acid, and boil 
for a few minutes. Allow the resulting precipitate to 
settle, colledt on a filter, and wash with water containing 
acetic acid. Dry, ignite, and weigh as TiOa. 

With pig irons the weighed portion, after the addition 
of the ammonium phosphate,* is dissolved in nitric acid, 
sp. gr. i'20, the solution taken to dryness, and baked. The 
dry mass, dissolved in hydrochloric acid, again taken to 
dryness, re-dissolved in hydrochloric acid, and, after di- 
luting the solution, the silica, &c., filtered off; the 
remainder of the operation being then similar to the 
above. 



A RECLAMATION. 



We have received a communication from Prof. Dr. C. 
Riffenbach, bearing date " Cairo, February 18, 1897." 
The author mentions that we insert in the Chemical 
News of February 12th a reprint of a paper by M. 
Gomberg, of Michigan, which appeared in the journal of 
the American Chemical Society, and which touches his 
region. 

Prof. Riffenbach informs us that he published this 
research by Gomberg in the Zeitschrift fur Analyt. 
Chemie, 1896, p. 466, as a Supplement, and requires us to 
notice his research. To this end he, simultaneously with 
this letter, sends a special reprint of the paper.f 



ELECTRIC SHADOWS AND LUMINESCENCE.^ 

By Prof. SILVANUS P. THOMPSON, D.Sc, F.R.S., M.R.I. 
(Concluded from p. 124). 

This will be a convenient place to mention a new effedt 
of X-rays which I have recently observed, and which is 
set down in the table. When X-rays fall upon a metal 
objedl eledlrified by an influence machine, they produce 
some curious changes in the nature of the discharge into 
the air. If the body is already discharging itself from 
some edge or corner in an aigrette or brush discharge 
(visible in darkness only) the size and form of the aigrette 
is much altered. Under some circumstances not yet in- 
vestigated, the incidence of X-rays causes the aigrette 
to disappear ; under, others, the X-rays provoke its ap- 
pearance. 

Since the publication of Rontgen's research the most 
notable advance that has been made has been in the direc- 
tion of improving the tubes. Rontgen himself has 
mostly employed a pear-shaped tube with a flat circular 
kathode near the top, producing a beautiful fluorescence 
of the lower part of the tube. He carefully verified the 
circumstance that the X-rays originate at that portion of 
the glass surface which receives the impadt of the 
kathodic discharge. They appear in fadl to be generated 
at the place where the kathode discharge first impinges 
upon the surface of any solid body. It is not necessary 
that the substance which is to adt as emitter of the X-rays 
should become fluorescent. On the contrary, it appears 
that the best radiators are substances that do not 
fluoresce, namely the metals. I have found zinc, mag- 
nesium, aluminium, copper, iron, and platinum to answer 
— the last two best.§ Mr. Porter, of University College, 
and Mr. Jackson, of King's College, have independently 
found out the merits of platinum foil, the former using 



* With phosphoric irons the addition of ammonium phosphate is 
not necessary, unless the titanium present is considerabl e. 

+ At the present date this reprint has not reached us. — Ed. C.N. 

t A Lecture delivered at the Royal Institution of Great Britain, 
Friday, May 8, 1896. 

§ (The author has since found metallic uranium to surpass all 
other metals). 



March 19, 1897. / 

an old Crookes tube designed for showing the heating 
effedt of the kathode discharge when concentrated by a 
concave kathode. On the table are some of the experi- 
mental forma (see Philosophical Magazine, August, 1896, 
p. 162) of tubes I have used. The best results are found 
when the kathodic discharge is diredted against an interior 
piece of metal — preferably platinum — which I term the 
antikathode (Comptes Rendtis, cxxii., p. 807), set obliquely 
opposite the kathode, and which serves as a radiatmg sur- 
face from which the X-rays are emitted in all dirediions. 
When experimenting with various forms of tube, I have 
spent much time in watching, by aid of a fluorescent 
screen, their emissive adtivity during the progress of ex- 
haustion. As already mentioned, X-rays are not emitted 
until the stage of minimum internal resistance has been 
passed. As the exhaustion advances, while resistance 
rises and spark length increases, there is noticed, by aid of 
the screen, a luminosity in the bulb, which, faint at first, 
seems to come both from the front face of the bit of 
platinum that serves as antikathode, and from the back 
face ; an oblique dark line (Fig. 11), corresponding to the 
plane of the antikathode, being observed in the screen to 
separate the two luminous regions. On slightly increasing 
the exhaustion the emission of X.rays from the back of 
the antikathode ceases, while that from the front greatly 
increases (Fig. 12), and is quite bright right up to the 
angle delimitedby the plane of the antikathode. There is 
something mysterious, needing careful investigation, in this 
lateral emission of X-rays under the impadof the kathode 
discharge. 

Of all the many forms of tube yet produced none has 
been found to surpass the particular pattern devised by 
Mr. Sydney Jackson (Fig. 13), and known as the " focus 
tube." It was with such a tube that I showed you at the 
outset the fundamental experiments of Rontgen. A con- 
cave polished kathode of aluminium concentrates the 
kathodic discharge upon a small oblique sheet of platinum, 
which, while adting as antikathode, serves at the same 
time as anode. Not only does the concentration of the 
kathodic discharge upon the metal cause it to emit X-rays 
much more vigorously, but it also has the efTect of causing 
them to be emitted from a comparatively small and definite 
source, with the result that the shadows cast by opaque 
objedts are darker. (Photographs were then thrown upon 
the screen, those taken with " focus" tubes showing re- 
markable definition of detail. Some of these were by 
Mr. J. W. Giffen ; others, showing diseased bones, &c,, 
taken by the ledlurer, and some by Mr. Campbell- Swinton 
and by Mr. Sydney Rowland, were also projedted). 

The objedtion has been taken that in these shadow 
photographs it is impossible to distinguish the parts that 
are behind from those that are in front. In a sense that 
is 80. But I venture to say that the objedlion not only 
can be got over, but has been got over. I cannot show 
the proof of my assertion upon the screen, because I can- 
not put upon the screen a stereoscopic view. But here in 
my hand is the Rontgen stereograph of a dead tame rabbit. 
Two views were taken, in which the X-rays were thrown 
in two different diredtions at an angle to one another. 
When these two views are stereoscopically combined, you 
observe the rabbit's body with the lungs and liver inside 
in their relative positions. The soft organs, which cast 
faint shadows almost indistinguishable amid the detail of 
ribs and other tissues, now detach themselves into different 
planes, and are recognisable distindtly. I now send up 
for projedtion in the lantern the two photographs that were 
taken at the beginning of my discourse, and which have in 
the meantime been developed. 

Turning back to the phenomena of luminescence,* 

• This very convenient term was suggested some six years ago by 
Wiedemann, to denote the many phenomena known variously as 
fluorescence or phosphoreseence. It refers to all those cases in 
which light is produced, whether under the stimulus of eleftric dis- 
charge, of heat, of prior exposure to illumination, or of chemical 
aftion, and the like, in which the light is emitted at a lower temper- 
ature than that which would be necessary if it were to be emitted by 
means of incandescence. 



Electric Shadows and Luminescence, 



^35 



permit me to draw your attention to the accompanying 
table of the different kinds of luminescence with which 
the physicist has to deal. 

Table II. 

Phenomenon. Substance in which it occurs. 

1. Chemi-luminescence .. Phosphorus oxidising in 

moist air ; decaying wood ; 
decaying fish ; glowworm ; 
firefly ; marine organisms, 
&c. 

2. Photo-luminescence .. Fluor-spar ; uranium-glass ; 

(a) transient = Fluor- quinine ; scheelite ; plat- 

escence. inocyanides of various 

bases ; eosin, and many 
coal-tar produdts. 

(b) persistent = Phosphot- Bologna-stone; Canton's 

escence. phosphorus and other sul- 

phides of alkaline earths ; 
some diamonds, &c. 

3. Thermo-luminescence .. Scheelite; fluor-spar. 

4. Tribo-luminescence.. .. Diamonds; sugar; uranyl 

nitrate ; pentadacylpara- 
tolylketone. 

5. Eledtroluminescence .. Many rarefied gases; many 

(a) Effluvio-luminescence. of the fluorescent and 
phosphorescent bodies. 

{b) Kathodo-luminescence Rubies, glass, diamonds, 
many gems and minerals. 

6. Crystallo-luminescence .. Arsenious acid. 

7. Lyo-luminescence .. .. Sub-chlorides of alkali- 

metals, 

8. X-luminescence .. .. Platino-cyanides, scheelite, 

&c. 

You will note the names given to discriminate from one 
another the various sorts of luminescence. Chemi- 
luminescence denotes that due to chemical adtion, as 
when phosphorus oxidises, or when the glowworm emits 
its cold light. Then there is the photo-luminescence of 
the bodies which shine when they are shone upon. There 
is the thermo luminescence of the bodies which shine 
when heated. There is tribo-luminescence caused by 
certain substances when they are rubbed. There is the 
kathodo-luminescence of the objedts placed in a Crookes 
tube. There is the crystallo-luminescence of certain 
materials when they become solid ; and the lyo-lumines- 
cence of certain other materials when they are dissolved. 
Lastly, there is the X-luminescence set up by the X-rays. 

Pausing on photo luminescence, here is an experiment 
to illustrate the difference between its two varieties, phos- 
phorescence and fluorescence. Light from an arc lamp, 
filtered from all rays except violet and ultra-violet, is 
thrown upon a disc to which rapid rotation is given by an 
eledtric motor. The disc is painted with two rings, one 
of sulphide of calcium, the other of tungstate of calcium. 
Though the light falls only on one patch, you note that 
the sulphide shows a continuous ring of blue light, for 
the emission of light persists after the stuff has passed 
out of the illuminating rays. The tungstate, on the other 
hand, shows only a short trail of light, the rest of the ring 
being non-luminous, since tungstate has but little per- 
sistence, The light has in fadl died out before the stuff 
has passed a quarter of an inch from the illuminating 
beam. This is a sort of phosphoroscope designed to 
show how long different materials will emit light after 
they have been shone upon. Those which show only a 
temporary luminescence are called fluorescent, while those 
with persistent luminescence are called phosphorescent. 
For many years it has been known that some diamonds 
are phosphorescent. Three such are here shown,* which, 
after exposure of one minute to the arc light, shine in the 
dark like glowworms. The most highly phosphorescent 
material yet produced is an artificial preparation of sul- 

* Kindly lent by Dr. T. H. Gladstone, F.R.S. 



136 



Electric Shadows and Luminescence, 



(Chbhical News, 
March 19, 1897. 




Fio. II. 



Fio. 12. 




Fio. 13. 



phide of calcium tnanufadlured by Mr. Home. The 
specimen exhibited has a candle-power of about ^^ candle 
per square inch after exposure for a few seconds to diredl 
sunlight ; but the brilliancy rapidly dies away, though 
there is a visible luminescence for many days. This sub- 
stance is also brightly luminescent in a Crookes tube, and 
less brightly under the influence of X-rays. 

Many substances, notably fluor-spar, have the property 
of thermo-luminescence, that is, they shine in the dark 
when warmed. Powdered fluor-spar dropped upon a hot 
shovel emits bright light. If, however, the spar is heated 
to a temperature considerably below red heat for some 
hours, it apparently comes to an end of its store of 
luminous energy, and ceases to shine. Such a specimen, 
even after being kept for some months, refuses to shine a 
second time when again heated. It has, however, long 
been known that the property of luminescing when 
warmed can be restored to the spar by passing a few 
eledtric sparks over it, or by exposing it to the silent dis- 
charge or aigrette. Wiedemann having found that the 
kathode rays produce a similar effedt, it occurred to me 
to try to find out whether any of these X-rays also would 
revivify thermo-luminescence. I have found that on ex- 
posure for twenty minutes to X-rays, a sample of fluor- 
spar which had lost its thermo-luminescent property by 




Fio. 14. 

prolonged heating was partially though not completely 
revivified. 

I referred earlier to the rays recently discovered by M. 
H. Becquerel. In February last M. Becquerel, and inde- 
pendently I myself (see Philosophical Magazine, July, 
i8g6), made the observation that uranium salts emit some 
rays which very closely resemble the X-rays, since they 
will pass through aluminium and produce photographic 
adtion. It remains to be seen whether these rays are 
identical with those of Rontgen. 

Finally, let me briefly exhibit two results of my own 
work. There is now shown (Fig. 14) the photographic 
shadow of two half-hoop ruby rings. One of them is of 
real rubies, the other of imitation stones. By artificial 
light it is difficult to distinguish one from the other, but 
when viewed by the X-rays there is no mistaking the 
false for the true. The real rubies are highly transparent, 
those of glass are pradlically opaque. 

After gaining much experience in judging by photo- 
graphy of the relative transparency of materials, I made 
a careful research (Phil, Mag., August, 1896) to discover 
whether these rays can be polarised. At first I used 
tourmalines of various thicknesses and colours. More 
recently I have tried a number of other dichroic sub- 
stances, — andalusite, sulphate of nickel, of nickel and 



CSBMICAL NBWB, 

March ig, 1897. 



Some Apparatus for Steam-disttllation, 



21 



ammonium, sulphate of cobalt, and the like. The method 
used for all was the following : — A slice of the crystal 
was broken into three parts. One part was laid down, 
and upon it were superposed the other two in such a way 
tliat in one the crystallographic axis was parallel, in the 
other perpendicular, to the crystallographic axis in the 
first piece. If there were any polarisation the double 
thickness where crossed in struiJlure would be moie 
opaque than the double thickness where the struduie was 
parallel. Not the slightest trace of polarisation could I 
observe in any case. Of numerous other observers who 
have sought to find polarisation, none has yet produced a 
single uncontestable case of polarisation. 

At the present moment interest centres around the use 
of luminescent screens for observing the Rontgen 
shadows, and in this diredtion some advances have been 
claimed of late. It should, however, not be forgotten 
that Rontgen's original discovery was made with a screen 
covered with platino-cyanide of barium. Here is a piece 
of card covered with patches of several different kinds of 
luminescent stuffs, several platino-cyanides, several sul- 
phides, and some samples of tungstate of calcium. Of 
these materials the brightest in luminescence is the 
hydrated platino-cyanide of potassium employed by Mr. 
Sydney Jackson ; the next brightest is a French sample 
of platino-cyanide of barium; platino-cyanide of stron- 
tium coming third. 

Using a focus tube of Mr. Jackson's improved pattern, 
enclosed in a box with a cardboard front, and taking a 
platino-cyanide screen, I am able in conclusion to demon- 
strate to all those of my audience who are within a few 
feet of the apparatus, the fadts that have so startled the 
world. You can see the bones of my hand and of my 
wrist. You can see light between the two bones of my 
forearm; while metal objeds, keys, coins, scissors, &c., 
enclosed in boxes, embedded in wood blocks, or locked up 
in leather bags, are plainly visible to the eye. 

Whatever these remarkable rays are, whether they are 
vortices in the ether, or longitudinal vibrations, or radiant 
matter that has penetrated the tube, or, lastly, whether 
they consist simply of ultra-violet light, their discovery 
affords us one more illustration of the fa(5t that there is 
no finality in science. The universe around us is not only 
not empty, is not only not dark, but is, on the contrary, 
absolutely full and palpitating with light : though there 
be light which our eyes may never see, and sounds which 
our ears may never hear. But science has not yet pro- 
nounced its last word on the hearing of that which is 
inaudible and the seeing of that which is invisible. 



PROCEEDINGS OF SOCIETIES. 

CHEMICAL SOCIETY. 
Ordinary Meeting, February 4th, 1897. 

Mr. A. G.Vernon Harcourt, President, in the Chair. 

Mr. H. L. Bowman was formally admitted a Fellow of 
the Society. 

Certificates were read for the first time in favour of 
Messrs. John Owen Alexander, 11, Avenue Road, South 
Norwood Park, S.E. ; John B. Ashworth, 16, Ducie Street, 
Prince's Park, Liverpool ; John Barclay, B.Sc, Avenue 
Cottage, near Bromsgrove, Worcestershire ; Frank 
Bastow, B.Sc, i, Braithwaite, Keighley ; William Dillon, 
7, Laurel Place, Chapel Lane, Armley, Lancashire; E. 
G. Guest, M.A., The Grammar School, Kirkham, Lanca- 
shire; T. Hartley, Gatwell Street, Bruton, Somerset; 
John Holmes, Crewe Villa, Putney Bridge Road, S.W. ; 
O. C. Johnson, 52, Thayer Street, Ann Arbor, Michigan, 
U.S.A. ; H. King, B.Sc, 4, North Street, Scarborough; 
H. M. Lloyd, 28, Vidloria Street, Merthyr; R. N. Lyne, 



Government Offices, Zanzibar ; C. H. Parker, Manor 
House, Tettenhall, Wolverhampton; S. Pollitt, B.Sc, 
19, Paulton Square, Chelsea, S.W. ; M. Wildermann, 
Ph.D., Davy-Faraday La'^oratory, Albemarle Street, W. 

Of the following papeis those marked * were read : — 

*io. ''Observations upon the Oxidation of Nitrogen 
Gas.^' By Lord Ravleigh, F.R.S. 

On the basis of Davy's assertion that the dissolved 
nitrogen of water is oxidised during ele(5trolysis, various 
attempts were made ; but they led to no useful result, 
even leaving it doubtful whether Davy's fatfts are corre<a. 

The influence of pressure upon the oxidation of nitrogen 
by the eledlric flame was next examined. It appeared 
that, while in a small vessel the effetft of increased pres- 
sure was favourable, but little advantage resulted when 
the vessel was large enough to give the maximum effed 
at a given pressure. The pressures compared were two 
atmospheres, one atmosphere, and half an atmosphere. 

The remainder of the paper is devoted to a detailed 
description of a large scale apparatus (shown working) in 
which 21 litres of mixed gases enter into combination per 
hour, at an expenditure of about i horse-power. 

Discussion. 

Professor Armstrong, referring to Lord Rayleigh's re- 
mark as to the importance of the platinum eleftrodes 
being red-hot, enquired whether there was any evidence 
that the platinum played a special part in the process. 

Professor Ramsay suggested, as an explanation of the 
better results obtained when a large vessel was employed, 
that nitric oxide was the first produdt, and that this sub- 
sequently combined with oxygen to form the peroxide. 

The President considered it probable that some of the 
oxide of nitrogen first formed was subsequently decom- 
posed by the heat of the flame itself, and that the large 
vessel, by presenting a large surface of alkaline liquid, 
favoured the rapid absorption of the oxide of nitrogen, 
and thus less was decomposed than would be the case in 
a smaller vessel, where the rate of absorption was smaller. 
He enquired with what proportion of nitrogen to oxygen 
combustion occurred most rapidly. 

Professor M'Leod remarked that he had made an ex- 
periment in the manner originally suggested by Cavendish, 
and had found that nitrite as well as nitrate was formed. 

Lord Rayleigh, in reply, said that the larger vessel 
apparently led to better results by increasing the facilities 
for absorption. He did not consider that the platinum 
played any special part in the process. The adtion seemed 
most rapid when the proportion of air to oxygen was as 
about 5 to 6, which corresponds with two of nitrogen to 
three of oxygen. He believed that both nitrite and 
nitrate were formed. The apparatus shown was suitable 
for the preliminary concentration, but not for the final 
purification of argon. 

•11. •' On some Apparatus for Steam-distillation." By 
F. E. Matthews, Ph.D. 

In this paper several forms of apparatus for automati- 
cally steam-distilling substances are described. 

Some solids of high melting-point may be separated by 
boiling the substance mixed with water in a flask fitted 
with a reflux condenser ; the solid substance adheres to the 
inside of the condenser, whence it can be removed from 
time to time. 

For liquids heavier than water, the flask in which the 
mixture is boiled is connected with ihe side tube of an or- 
dinary distilling-flask ; this disiilling-flask, filled with 
water up to the side-tube, serves as the receiver. Into 
the neck of the receiver, and passing below the surface of 
the water, a bent Liebig's condenser is fitted which has 
the peculiarity of having a hole made in it a short distance 
above the level of the water in the receiver. On boiling 
the mixture in the flask, the vapours pass up the side- 
tube of the receiver into the upper portion of its neck and 
thence through the hole in the receiver, when condensa- 
tion takes place. The condensed liquids run down the 



138 



Wechsler*s Method /or the Separation of Fatty A ctds. 



Cbbmical Nbws, 

March 19, 1S97. 



condenser to the water-level in the receiver, where a drop 
of the heavy fluid sufficiently large to sink is formed from 
time to time. The condensed liquids displace their own 
volume of water, which flows from the receiver through 
the side-tube back again to the boiling-flask. In all cases 
in which vapour is passing in one diredion in a tube, and 
water in the other, the advantage of perforating the tube 
near its lower end is pointed out. 

For liquids lighter than water, the apparatus consists 
of the boiling-flask, which is an ordinary distilling-flask ; 
this is conneded by the upper opening to an upright tube 
furnished with a J-piece. The top of the upright tube is 
connedted to the condenser, the lower end dips two or 
three inches into a Woulfe's bottle, containing water in 
sufficient quantity, which serves as the receiver. Through 
another neck of the Woulfe's bottle, a second tube passes 
from the bottom of the bottle and is connected to the side- 
tube of the boiling-flask. The mixed vapours pass from 
the boiling-flask into the upright T-tube, thence into the 
condenser; there becoming condensed, they fall down 
into the J-tube, producing a column of liquid which forces 
water from the bottom of the receiver back into the 
boiling-flask through its side-tube. 

A modification of this apparatus dispenses with the 
necessity of having an indiarubber connection exposed to 
the hot vapour. In this modification the boiling-flask is 
an ordinary plain flask. This is connedted to the con- 
denser by a side-tube blown on to the upright tube. The 
water returns to the boiling-flask through another T-tube, 
blown on to the side-tube of the upright tube. For con- 
veniently emptying the receiver without dismantling the 
apparatus, a separating funnel with two necks may re- 
place the Woulfe's bottle of the previous apparatus. 

Many liquids bump badly when boiled with water ; this 
can generally be got over by introducing a zinc-platinum 
couple into the boiling- flask. The temperature of the 
water in the boiling-flask may be raised by dissolving 
suitable substances, such as sulphuric acid or calcic 
chloride, in it, or liquids of higher boiling-point may be 
used. 

*12. " Researches in the Stilbene Series." I. By John 

J. SUDBOROUGH, Ph.D. 

The author has obtained benzil as one of the products 
of the a(5tion of zinc dust and acetic acid on benzoin ; if 
the a(5tion is continued the benzil disappears and the chief 
produdt is deoxybenzoin. The formation of an oxidation 
produdt of benzoin by the action on it of zinc dust and 
acetic acid appeared so remarkable that the author has 
studied the a(5tion of acetic acid alone on benzoin, and he 
finds that small quantities of benzil are formed if benzoin 
is heated with six times its weight of glacial acetic acid 
on the water-bath for eight — nine hours. 

By the adtion of phosphorus pentachloride on deoxy- 
benzoin a solid chlorstilbene has been obtained, which 
differs from Zinin's oily compound. It melts at 45°, 
yields a dibromide and a dichloride, also with nitrous 
fumes two compounds probably represented by the for- 
mula PhCHNOaCClNOa-Ph (m. p. 128°) and 
Ph'C{N02):C(N02)-Ph (yellow prisms, m. p. 104—105°). 

An oily compound can be obtained by the adtion of 
phosphorus pentachloride on deoxybenzoin at low tem- 
peratures. The oil contains the same amount of chlorine 
as solid chlorstilbene. 

Methyldeoxybenzoin and ethyldeoxybenzoin on treat- 
ment with phosphorus pentachloride can be made to yield 
both oily and crystalline compounds, analysis of which 
points to their being methyl- and ethyl-chlorstilbenes. 
Solid methylchlorstilbene melts at 124°, and the corre- 
sponding ethyl compound at 60°. The dichlorides and 
dibromides are also described. The question as to the 
nature of the oily compounds has not been settled; the 
author describes a method by which he proposes to deter- 
mine whether they are merely slightly impure forms of 
the solid compound, true stereo-isomerides, or strudturally 
isomeric with the solid compounds. 



*I2, " Diortho-substituted Benzoic Acids. III. Hydro- 
lysis of Substituted Benzatnides." By John J. Sud- 
BOROUGH, Ph.D., Percy G. Jackson, and Lorenzo L. 
Lloyd. 

In order to determine whether diortho-substituted 
benzamides exhibit the same remarkable degree of 
stability towards hydrolysing agents as characSterises the 
diortho-benzoyl chlorides {Trans., 1895, Ixvii., 587) and 
ethereal salts, the authors have investigated the following 
compounds : — 

Ortho-, meta-, and para-brombenzamide ; 2:4-, 2:6-, 
and 3 : 5-dibrombenzamide ; 2:4:6- and 3:4: 5-tribrom- 
benzamide ; 2 : 4 : 6-trichlorbenzamide ; 2 : 4 : 6-trimethyl- 
benzamide (mesitylformamide) and mesitylacetamide, 
CeHaMes'CHz'CONHa. Of the three mono-substituted 
brombenzamides the ortho-compound proves to be some- 
what more stable in the presence of boiling (30 per cent) 
sulphuric acid than the meta- and para-compounds. This 
agrees with the properties of the corresponding methylic 
monobrombenzoates and of the monobrombenzoyl 
chlorides. 

Of the three dibromamides the 2:6- or di-ortho- 
substituted compound proves to be the one most difficult 
to hydrolyse by means of 75 per cent sulphuric acid, and 
again of the two tribromamides the 2:4:6- or symmetri- 
cally substituted amide is much more stable than the 
isomeric 3:4: 5-tribrombenzamide. 2:4: 6-trichlor- 
benzamide although not hydrolysed so readily as 2:4- 
and 3 : 5-dibrom- and 3 : 4 : 5-tribrombenzamide is less 
stable than the corresponding 2:4: 6-tribrom-compound. 

The methyl derivatives could not be investigated as re- 
gards their hydrolysis with 75 per cent sulphuric acid, as 
they are charred and decomposed by this means. To- 
wards 30 per cent sulphuric acid the mesitylformamide is 
much more stable than the corresponding acetamide. 

In the course of this investigation the following new 
compounds have been obtained: — 3 :5-Dibrombenzamide, 
m. p. 187°; 2 : 4 :6-tribrombenzonitrile, m. p. 127°; 
2 : 4 : 6-tribrombenzamide, m. p. 193 — 194°; 3:4: 5-tri- 
brombenzamide, m. p. 199°; 2 : 4 : 6-trichlorbenzonitrile, 
*"• P* 75° » 2:4: 6-trichlorbenzamide, m. p. 177" ; mesityl* 
formamide, m. p. 105° ; mesitylacetamide, m. p. 210°. 

*i4. " Conversion of Camphoroxime into Methylcam* 
phorimine and Camphenylnitramine." By M. O. Forstbr, 
Ph.D. 

Further investigation of the base obtained on heating 
camphoroxime in sealed tubes with methylic iodide has 
proved it to be the methyl-derivative of Tiemann's cam- 
phorimine ; it therefore has the formula^- 
,CHa 



C8H14 



C:N-Me 



and not, as appeared probable from the preliminary ex- 
amination (Proc, 1895, xi., 145), the formula CizHigN. 
This is shown by its behaviour towards concentrated 
hydrochloric acid at 200°, giving rise to camphor and 
methylamine. 

Methylcantphorimine hydrochloride and methiodide melt 
at 270° and 231 — 232° respedtively ; the perbromide has 
also been prepared. 

The adlion of dilute nitric acid on camphoroxime, if 
interrupted after a few minutes, gives rise to camphenyl- 
nitramine, which is also formed when a solution of the 
oxime in chloroform is treated with nitrogen peroxide. 

An acid solution of potassium permanganate converts 
camphoroxime into an unstable nitroso-derivative, which 
separates from the liquid as a sticky, green mass ; when 
preserved in the desiccator the substance deliquesces, 
and loses its green colour, the yellow residue yielding 
camphor when distilled in an atmosphere of steam. 

15. " Note on Wechsler's Method for the Separation of 
Fatty Acids." By Arthur W. Crossley. 

Wechsler {Monatsh., 1893, xiv., 462) has described a 
method for the separation of fatty acids, the principle of 
which method is contained in the following statement. 



Chemical News, i 
March 19, 1897. ( 



Formation of Dtthionic A cid^ 



If to a mixture of two fatty acids four-fifths of the 
caustic soda necessary to neutralise them be added, and 
the whole steam-distilled, the distillate contains the pure 
higher-boiling acid. From the residue of the distillation 
a further three-fifths of the acids are set free by addition 
of sulphuric acid, and the whole distilled in steam. 
Finally, the remaining fifth of the acid is set free, and in 
this case the distillate contains the lower-boiling acid in 
a pure condition. 

The purity of the acids contained in the various distil- 
lates was proved by converting them into silver salts and 
subsequent analysis of these salts. 

After trying this method of separation, with very un- 
satisfactory results, on a mixture of fatty acids obtained 
in a research on which Professor Perkin and the author 
have been engaged for some time past, it was thought ad- 
visable to test some of Wechsler's experimental data. 

Accordingly, Wechsler's experiments have been care- 
fully repeated and results obtained which do not agree 
with that author's. 

As Wechsler always worked with equimolecular propor- 
tions of fatty acids, the results of some experiments are 
recorded in which varying proportions of fatty acids were 
employed. In every case the results were unsatisfa(5tory, 
(or even when using three molecules of the lower to one 
of the higher boiling acid, the former was not obtained 
pure in the last distillate, and the first distillate contained 
a decided mixture of the two acids. 

It is therefore to be concluded that Wechsler's method 
does not give such good results as the author suggests, 
nor can it in any way be looked upon as a satisfadory 
method for separating mixtures of fatty acids. 

16. '* On the Crystalline Structure of Gold and Platinum 
Nuggets and Gold Ingots." By A. Liversidge, LL.D,, 
F.R.S. 

In view of the theory that gold nuggets are built up of 
concentric layers deposited round a central nucleus, the 
author has examined a large number of specimens from 
various sources. The nuggets were ground down, or 
sliced through, to obtain seiflions, which were polished 
and etched by suitable solvents. They all possessed a 
well-marked crystalline strucfture, and usually enclose 
foreign substances. The crystalline strudture is not in- 
compatible with an aqueous origin ; and the author sug- 
gests that the gold has been slowly deposited from solu- 
tion, either at ordiinary or at high temperatures ; the 
nuggets being more or less rolled masses of gold which 
have been set free from disintegrated veins. 

17. " On the presence of Gold in Natural Saline Deposit^ 
and Marine Plants." By A. Liversidge, LL.D., F.R.S. 

The author gives a preliminary account of the results 
of the examination for gold of rock salt, sylvine, and other 
similar saline deposits, bittern, sea-weed, kelp, oyster- 
shells, &c. The process of determination used was to 
add from 0*5 to 5 grms. of ferrous sulphate to the unfiltered 
solution of 100 to 1000 grms. of the salt in water. The 
resulting precipitate was then scorified with lead and 
cupelled. The natural salts contained from i to 2 grains 
of gold per ton, whilst kelp and bittern furnished in some 
cases as much as from 14 to 20 grains. 



Ordinary Meeting, February i8th, 1897. 

Mr. A. G. Vernon Harcourt, President, in the Chair. 

Mr. E. Haynes Jeffers was formally admitted a Fellow of 
the Society. 

Certificates were read for the first time in favour of 
Messrs. Herbert William Leyland Barlow, M.A., M.B., 
Holly Bank, Urmston, Manchester; Frederick Filmer de 
Morgan, Andely Lodge, Caeran Park, Newport, Mon- 
mouthshire ; Louis Charles Oeverell, Onslow House, 
Worthing; William James George Lasseter, B.A., 10, 



139 ; 

Stanley Road, Oxford ; Harry Edward William Phillips, 
B.A., 47, Chalfont Road, Oxford ; William Herbert 
Waite, B.A., Park Road, Halifax; Charles Thomas 
Foster Watts, 7, Cambrian Crescent, Chester; John 
Welsh, I2A, Seller Street, Chester. 

The certificate of the following candidate, recommended 
by the Council under Bye-law I. {3), was also read : — 

Frederic Hewlett Burton-Brown, Simla, India. 

It was announced that the following changes in the 
Officers and Council were proposed by the Council : — 

As President — Professor James Dewar, M.A., LL.D., 
F.R.S., vice Mr. A. G. Vernon Harcourt, M.A., D.C.L., 
LL.D., F.R.S. As Vice-Presidents — Proiessor W. 
Ramsay, Ph.D., F.R.S., and Professor J. Emerson 
Reynolds, M.A., F.R.S., vice Professor James Dewar, 
M.A., LL.D., F.R.S., and Mr. Horace T. Brown, F.R.S. 
As Ordinary Members of Council— Messrs. C. T. Heycock, 
M.A., F.R.S. ; Rudolph Messel, Ph.D. ; Tom Kirke Rose, 
D.Sc. ; and Alexander Scott, M.A., D.Sc, vice Messrs. 
Bernard Dyer, D.Sc; G.Harris Morris, Ph.D.; W. A. 
Shenstone ; and T. Stevenson, M.D. 

It was also announced that the Council had awarded 
the LongstafT Medal to Prof. William Ramsay, F.R.S., 
for the discovery of helium, and his share in the investi- 
gation of argon. 

Messrs. H. Brereton Baker, F. D. Chattaway, and 
John Shields were appointed to audit the Society's 
accounts. 

Of the following papers those marked * were read. 

*i8. " The Formation of Dithionic Acid in the Oxida- 
tion of Sulphurous Acid by Potassium Permanganate." 
By T. S. Dymond and F. Hughes. 

When a solution of sulphurous acid is titrated with a 
solution of potassium permanganate, decolorisation of 
the permanganate ceases when only 89 per cent of the 
quantity required to oxidise the sulphurous acid to sul- 
phuric acid has been used. This is due to the formation 
of dithionic acid in addition to sulphuric acid. The pro- 
portion of dithionic acid produced is constant, and is not 
influenced by either the dilution or the temperature, or 
the acidity of the solution. Its produdtion, therefore, 
appears to be an essential part of the readlion, and to be 
due to the weak oxidising adlion of the permanganate in 
a final stage of its redudtion. The sulphuric and 
dithionic acids produced are in the proportion required 
by the supposition that manganese heptoxide is first re- 
duced to the red oxide with produdtion of sulphuric acid, 
and further reduced to the monoxide with produdtion of 
dithionic acid. When, however, sulphurous acid is 
treated with the red oxide, sulphuric acid is the only 
produdl. 

Discussion. 

The President said that he had worked, a number of 
years ago, upon the readtion between solutions of potas- 
sium permanganate and sulphurous acid, before sodium 
thiosulphate had come into use for estimating iodine. In 
making determinations without excluding air from the 
water, he had found that the quantity of permanganate 
used was far less than the amount necessary for the com- 
plete oxidation of the sulphurous acid. He found that 
the sulphurous acid was oxidised by the atmospheric 
oxygen dissolved in the water, and so progressively as 
the water gradually dissolved the oxygen in the air lying 
over it. As the result of a number of experiments, he 
proved that the diminution in the quantity of perman- 
ganate required increased with the dilution of the sul- 
phurous acid, and also that if the water was boiled until 
air-free the quantity of permanganate used was larger ; 
but he had not obtained such constant results as Messrs. 
Dymond and Hughes. He had tried the experiment of 
adding a small quantity of manganous sulphate to the 
dilute solution, and had found that this salt also was able 
to determine the oxidation of sulphurous acid by atmo- 
spheric oxygen. He thought the author's experimenta 



140 



Mechanical Cause of Homogeneity of Structure and Symmetry, {^MaJ'chig.'SffJ'' 



extremely interesting in showing the constant produdiion 
of dithionic acid. 

Dr. Scott thought it would be worth while to try the 
effedt of manganic sulphate in oxidising sulphurous acid. 

Prof. DuNSTAN suggested that it would be interesting 
to determine whether the formation of dithionic acid oc- 
curred at the positive ele(5trode during the eledirolysis of 
a solution of sulphurous acid, since it seemed possible 
that the dithionic acid might be formed by the oxidation 
of sulphurous acid in much the same way as persulphuric 
acid was formed by the oxidation of sulphuric acid. He 
understood that in the remarkable adion of manganous 
sulphate described by the President this salt undergoes 
no change. 

(To be continued). 



PHYSICAL SOCIETY. 
Ordinary Meeting, March 12th, 1897. 

Mr. Shelford Bidwell, President, in the Chair. 

Mr. William Barlow read a paper on " A Mechanical 
Cause of Homogeneity of Structure and Symmetry, 
Geometrically Investigated, with Special Application to 
Crystals and to Chemical Combination." Illustrated by 
Models. 

The author has previously established that every homo- 
geneous strudlure displays one or other of the thirty-two 
kinds of crystalline symmetry. He now shows that 
homogeneous struftures possessing most, if not all, of 
these kinds of symmetry may be produced mechanically, 
as the equilibrium arrangements of assemblages of 
mutually - repellent particles; and, also, that these 
mechanical systems of particles exhibit charadleristics 
entirely analogous to certain crystalline and other pro- 
perties of matter. The fundamental concept may be sum- 
marised thus : — A number of different kinds of mutually- 
repellent particles dispersed through space, the amount 
of this repulsion being some inverse fundtion of the dis- 
tance between the particles concerned ; the particles are 
destitute of polarity, and the difference in kind consists 
in a difference in the degree of mutual repulsion which 
two particles exercise, according to the kinds taken. It 
is further premised that the assemblage is agitated, so as 
to render unstable all but the final equilibrium arrange- 
ment ; and a means is provided for linking the particles 
symmetrically, and unlinking them, under certain circum- 
stances, so as to modify the repulsion between the 
particles affedled. The data thus summarised may be 
regarded as merely provisional, because the making of the 
equilibrium arrangement one in which " closest packing " 
prevails, is the objedt primarily aimed at ; and these con- 
cepts are mere devices for attaining this end. By the 
employment of particles of different kinds, a large amount 
of variety is provided for. The first step taken is to de- 
duce the law of '• closest packing," which runs thus : — 
Every assemblage of mutually-repellent particles will con- 
tinually approximate to, or strive after, that relative 
arrangement of the particles composing it, in which it 
has come, at every part, to occupy a minimum of space 
under a given general pressure, or average repulsion, be- 
tween the particles. This law aifts on all assemblages of 
the nature defined, however numerous the kinds of 
particles composing them ; but for its effedls to be trace- 
able, a very limited number of kinds must be present. 
Passing from assemblages consisting of a single kind of 
particle, the author takes a very simple case of two kinds 
of particles confined to a plane, and shows what type of 
symmetry will be produced when equilibrium is realised. 
Very simple cases of particles in space are then taken, 
and it is shown that a large number of different kinds of 
symmetry are displayed by the equilibrium arrangements 



produced when there is variety in the relations between 
the repulsions. To illustrate " close packing," stacks of 
balls of various sizes are employed ; but it is pointed out 
that the conditions of statical equilibrium of the particles 
are not always adequately expressed in this way ; 
although every case of the latter kind can be represented 
approximately by a case of the former kind, possessed of 
the same order of symmetry. Very slight variation in the 
relations between the repulsions alters the form of the 
equilibrium arrangement ; sometimes merely changing 
the angle without affefting the type; sometimes, when it 
passes some critical point, bringing about an alteration 
iii type. Changes of the first kind resemble the change 
in crystal form caused by variation of temperature ; whilst 
those of the latter kind, especially when associated with 
re-arrangement of the particles, are analogous to poly- 
morphism. In many cases the arrangement of the 
particles is such that some may be removed without 
affedling the distribution of the remainder, and without 
destroying the "close packing," If, therefore, other 
particles, exercising a slightly less repulsion, be sub- 
stituted for the removed, inoperative, particles, the only 
resulting change consists in a diminution of the pressure 
on the particles surrounding them. A species of isomor- 
phism is in this way realised. 

When the particles of an assemblage are partially con- 
nedled by hypothetic linking in a symmetiical manner, 
similar groups are formed ; but, in order that the forma- 
tion of such groups may not be arbitrary, the partitioning 
which is produced must have as complete symmetry as 
that of the partioned strudure. In consequence of this, 
some kinds of groups are not diredlly obtainable by sym- 
metrical partitioning of a homogeneous strudure ; but it 
is always conceivable that they may be included in the 
larger groups of some more complex constellation, and 
that they may be subsequently separated to form an 
assemblage by themselves. Consequently, very intricate 
results may be reached by successive steps. Symmetrical 
intermixture, linking, and unlinking, succeeding one 
another until complicated groups are built up, for the pro- 
dudlion of which such an agency as "close packing" 
appears at first sight inadequate. Having called attention 
to a large number of arrangements, some capable and 
some incapable of symmetrical partitioning intogroups of a 
single kind, some linked and some unlinked, the author con- 
tends to.have established the following two propositions : — 
(i) The nature of the symmetry displayed by a homo- 
geneous assemblage of mutually-repellent particles of dif- 
ferent kinds in equilibrium, depends on the relations sub- 
sisting between the repulsions exercised by these particles. 
(2) The assemblages belonging to all of the thirty-two 
classes of crystalline symmetry result from the funda- 
mental law of " close packing," when the relations be- 
tween the different repulsions take the widest possible 
range of variety. Links which restrain the adion of the 
repulsion can be present between some of the particles 
in some cases. The author refers to crystal '• twinning," 
and points out that the adlion of dimorphism is competent 
to produce analogous *' twinning " of symmetrical 
assemblages of linked particles. A number of other pro- 
perties of linked assemblages analogous to those of crys- 
tals are also described. In the domain of chemistry the 
author cites the continually accumulating experimental 
evidence of the existence of geometrical arrangement in 
the molecule, both that established stereochemically and 
that derived from the study of isomerism, as revealing a 
state of things precisely such as is arrived at by the law 
of '• closest packing " in assemblages afterwards broken 
up into similar groups of particles. Attention is called to 
many groupings of the latter order fulfilling very exadlly 
the conditions of disubstitution in the case of many car- 
bon compounds. While he does not regard his work as 
throwing any light on the nature of change of state, or 
change of bulk, the author observes that the distribution 
in precise proportions of the constituents that must ob- 



Chbmical Mbws, 
March ig, i8g7. 



Compounds of Nitrogen and Argon, 



141 



viously accompany or precede a chemical combination, 
may fairly be claimed as a resemblance to the regular 
intermixture brought about according to the law of 
•• closest packing," He further suggests that the reason 
why some bodies do not readily interadt may be due to 
the " close packing " of one or both. 

Prof. Herschel said he was f articularly pleased with 
the models. He thought it probable that a very wide 
application would be found for the author's results. There 
was no doubt much to be learnt from models built up of 
spheres of two or more sizes, but it would be necessary 
to learn a great deal more about these symmetrical ar- 
rangements before they could be applied with any degree 
of certainty. 

Mr. Fletcher said it was impossible to criticise the 
paper without long and careful study. From certain 
hypotheses the author had deduced a law of •' closest 
packing " that seemed adequate to explain many results 
observed by chemists and crystallographers ; at the same 
time admitting that the law might be presumed from 
other reasoning. By his models he had tried to present a 
pidture not of the forms of atoms or molecules, but 
merely analogical representations of the probable struc- 
ture of particles. Hitherto the research had been confined 
to determining the possible arrangements of particles all 
of one kind, but here were examples of packed spheres of 
various sizes. It was not quite clear how, in an ele- 
mentary substance, there could be such a strudlure, 
although there certainly were cases of polymorphism 
awaiting explanation, as for instance with sulphur. The 
paper, with its 188 pages of MS., represented a vast 
amount of clear thinking, and many years of admirable 
work. 

Prof. Adams called the attention of Fellows of the 
Physical Society to the Museum at King's College, where 
were the original models as made and used by the early 
investigators of this branch of Physics. 

Prof. MiERS (communicated, too late for reading) — The 
principle of "close packing" was not new, but Mr. 
Barlow was the first to extend it to explain solution, 
diffusion, and stereochemical problems. His remarks on 
the growth of curved crystals, vicinal faces, and pseudo- 
symmetrical crystals were open to criticism. With regard 
to vicinal faces, however, lencite seemed to be a mineral 
in accord with his hypothesis. The author regarded a 
crystal as consisting of mutually repellent particles of 
different sorts : this seemed a very right way of attacking 
the problem of crystal strudlure, and would explain some 
recent observations of Rinne on crystals consisting of 
water particles and silicate particles. Further, Mr. 
Barlow had considered the way in which an assemblage 
might be broken up by the loosening of the ties, and the 
change of partners, among individual members. That is 
to say, he had considered crystallisation and solution, 
features quite ignored by ordinary theories. His view of 
crystal strudture failed to explain why crystals should 
have faces, and gave no hint as to the controlling forces 
which keep mutually-repellent particles together. Never- 
theless it suggested, among other striking analogies, those 
bearing on the relationship between crystal structure and 
chemical constitution, and the irregularities of crystals, 
such as were commonly negledted in accepted theories. 
Mr. Barlow had opened up a very promising line of 
inquiry. 

Mr. Barlow, in replying, said he greatly appreciated 
the interest shown in his work. 

The President then proposed a vote of thanks to the 
author, and the meeting was adjourned until March 26th. 
At the invitation of Dr. S. P. Thompson, the Society 
will on that occasion meet at the Technical College, 
Leonard Street, Finsbury. 



EDINBURGH UNIVERSITY CHEMICAL 

SOCIETY. 

Last Ordinary Meeting of the Session, March 8th, 1897. 

Mr. C. Saintsbury in the Chair. 

Dr. J. E. Mackenzie read a paper '* On the Compounds of 
Nitrogen and Hydrogen." 

Five such compounds are at present known: — NH3, 
ammonia; N2H4, hydrazine; N3H, azoimide; N4H4, 
ammonium nitride ; and N5H5, hydrazine nitride. 

Ammonia does not call for description here. The 
other substances are of comparatively recent discovery, 
the chemist to whom we owe most of our knowledge of 
them being Theodor Curtius. In 1883 he commenced a 
series of researches on amido- acids. In the course of 
these he obtained the hydrochloride of ethyl amido- 
acetate, a beautiful crystalline substance, which, on 
being diazotised, yielded ethyl diazo-acetate {Ber,, xvi., 
2230) :— 
HCl-HaNCHaCOOCaHs + NO2H = 

= NatCHCOOCaHj + 2H2O + HCI. 

By similar treatment other amido-acid esters yielded 
diazo esters {your. Prak. Chemie, [2], xxxviii., 404), 
these being oils, slightly soluble in water, miscible with 
the ordinary organic solvents, having a charadteristic 
odour and being volatile. The diazo-acetic ester, on 
treatment with dilute caustic soda, gave the sodium salt, 
which, on being acidified with dilute sulphuric acid, split 
off nitrogen and formed glycollic acid, — 

2N2CH-C00Na -f- H2SO4 + 2H2O = 

= 2N2 -f 2CH2(OH)COOH + 2Na2S04. 

On the other hand, if concentrated caustic soda were 
used, a polymer, triazo-acetic acid, was formed, which, by 
the adlion of acids, broke up into hydrazine and oxalic 
acid, — 

(N2CH)3(COOH)3 + 6H,0 = 3N2H4 + 3(COOH)2. 

Thus, in 1887, the sulphate of hydrazine was obtained. 
Other salts were also formed, and from them Curtius sepa- 
rated hydrazine hydrate, N2H4,H20, by distilling with 
strong bases such as CaO or NaHO. The hydrate is a 
colourless, fuming liquid, b.p. iig°. It destroys cork and 
rubber, and is a powerful reducing agent and poison. 

In 1895 Lobry de Bruyn isolated free hydrazine : — 
(a) by mixing anhydrous solutions of hydrazine hydro- 
chloride and sodium methylate, separating the sodium 
chloride and fradtionating the resulting solution under 
reduced pressure,— 

N2H4-HC1 -I- NaOCzHa = NaCl + CH3OH -|- NaH4; 

(6) by dehydrating the hydrate by means of barium oxide 
and distilling under reduced pressure. 

Hydrazine melts at -f- 1-4° and boils at 113*5°, under 
761 m.m., or at 56° under 71 m.m. pressure of mercury. 
It is one of the strongest reducing agents. In chlorine 
it takes fire spontaneously, HCI and N being formed. 
With sulphur it readts in cold, with produdtion of SHj 
and N. It displaces ammonia from solutions of ammo- 
nium salts. With acids it forms two series of salts, e.g., 
N2H4.HCI and N2H4,2HCI. Its condensations with 
aldehyds and ketones are very important. 

Other methods of preparing hydrazine are those of 
Pechmann (Ber., xxviii., 1847 and 2374), Thiele and 
Duden {Ber., xxvii., 3498). That of the latter is the 
simplest. By the adtion of sulphurous acid on potassium 
nitrite, potassium dinitroso-sulphonate is formed, which 
on redudtion by sodium amalgam eventually affords 
hydrazine, — 

^^>N-N0 + 6H = ^^°|>N-NH2-|-H20-|-K0H = 

= H2N-NHa + K2S04. 



142 



Chemical Notices from Foreign Sources. 



I Cbbmical Nbws, 
I March ig, 1897. 



In 1890 Curtius published his first paper on " Azo- 
imide, N3H " {Ber., xxiii., 3023). By means of hydrazine 
benzoyl-glycollic ester is converted into benzoyl hydra- 
zide, — 

C6H5CO-OCH2-COOC2H5 + 2N2H4=C6H5CONH-NH2+ 
+NH2-NHCH2COOH + C2H50H, 

which on diazotising yields benzoyl azbimide, — 

C6H5-CONH-NH2 + NOOH = C6H5-CON3+2H20. 

This decomposes when boiled with caustic soda, — 

C6H5CON3+2NaOH = C6H5COONa + N3Na+H20, 

forming sodium nitride, from which azoimide is set free 
by the adtion of acids, — 

NgNa + H2SO4 = N3H + NaHS04. 

By careful fraiftionation a solution of gi per cent N3H 
was obtained, which was dehydrated by calcium chloride. 
Azoimide is a colourless liquid with an unbearable odour, 
boils at 37°, and is miscible with water and alcohol. It 
is frightfully explosive ; 5 c.grms. exploded in a barometer 
tube shattering the glass to a powder and spreading the 
mercuiry as a fine dust. 

Angeli's method of obtaining azoimide is probably the 
simplest. On mixing solutions of hydrazine sulphate and 
silver nitrite, silver nitride separates, — 

N2H4,H2S04 + AgNOz = N3Ag + 2H2O + H2SO4. 

Thiele's method, starting from amido-guanidine, and 
Wislicenus's from sodamide, are also important. 

The metallic salts of azoimide resemble those of hydro- 
chloric acid very much, except that they are explosive. 
Ammonium nitride, N3NH4, is the most perfedt explosive 
known; i kilo, is calculated to liberate 1148 litres of gas 
at 0° and 760 mm. {Bull. Soc. Chim. Paris, xi., 744). 

Hydrazine nitride, N3N2H5, is formed by mixing hydra- 
zine hydrate and ammonium nitride or free azoimide. It 
is a crystalline substance, which behaves like gun-cotton, 
burning quietly on exposure to fiame, but exploding on 
detonation or sudden heating. 



NOTICES OF BOOKS. 



A Handbook for Brewers ; being a Pradlical Guide to the 
Art of Brewing and Malting, embracing the Conclusions 
of Modern Research which bear upon the Practice of 
Brewing. By Herbert Edwards Wright, M.A., 
Author of a '• Handbook for Young Brewers." Second 
Edition, thoroughly Revised. London : Crosby Lock- 
wood and Son, 7, Stationers' Hall Court, Ludgate Hill. 
1897. Small 8vo., pp. 516. 
This work is of an extremely comprehensive charaiSter. 
It is concerned not merely with the chemistry of the 
brewing process, but also with the mechanical construdlion 
of brewery plant in the widest sense of the term. 
Micro-biology and the use of the microscope are very 
carefully considered. We cannot, however, agree with 
the author's rather unfavourable estimate of immersion 
lenses. Several little precautionary hints are given which 
prove the author to be a pradical microscopist. 

The controversies between Liebig, Pasteur, Traube, 
and Brefeld are fairly expounded. 

The commercial phase of the brewer's business is next 
expounded. 

As regards the theoretical considerations, Mr. Wright 
ventures on the opinion that " the final limit of subdivision 
has probably never been reached." The *' pleomorphic 
craze" of A. G, Salamon and others meets with little 
countenance. But such questions have a very subordi- 
nate interest for the brewer, or indeed for any technical 
chemist. 
We are glad to find the admission that Demerara sugar 



(when genuine) is perhaps the best and purest sugar in 
the world (p. 148). On the opposite page it is mentioned 
that sugars having a large bold crystal are not beloved by 
the trade, as they oppose certain difficulties to the mys- 
terious process known as handling — which, by the way, 
avenges itself on the men by whom it is effedted. 

An entire and ably written chapter is devoted to water 
and its impurities. It is admitted that soluble mineral 
matter may be tolerated by the brewer to an extent larger 
than would be tolerated in a drinking or culinary water, 
or in that employed in the tindtorial art. The injurious 
adtion of salts of magnesium in appreciable quantities, 
we submit, can scarcely be contested. Nitrites in a 
brewing water he objedls to on the authority of Emile 
Laurent. 

The author lays little weight upon Prof. Frankland's 
previous sewage pollution. He attaches more weight 
than does Prof. Wanklyn to the possible presence of 
phosphoric acid in waters, and he considers that waters 
which after boiling and filtration — we would add by the 
Chamber land- Pasteur process — develop organisms with 
the Heisch test, probably contain organic matter of an 
albuminous charadter, and should be used (if at all) with 
great caution. 

The author quotes the conclusion of Jorgensen, that 
for brewing purposes it is only necessary to know whether 
the water contains organisms capable of developing in 
wort or beer. 

Mr. Wright reminds his readers that the presence of 
free carbonic acid in waters is by no means a proof of 
purity. 

In speaking of materials used as partial substitute for 
malt, the author mentions that beet-sugar is far inferior 
to cane-sugar for brewing purposes. 

This book will be found most useful not merely to 
brewers, whether learners or pradtitioners, but to technolo- 
gists in general. 



CORRESPONDENCE. 



LOST PLATINUM. 

To the Editor of the Chemical News, 
Sir, — Three platinum basins have recently disappeared 
from this laboratory, and, as it is just possible that some 
amongst your numerous readers may have been buying 
second hand platinum basins, I append the following par- 
ticulars, in the hope — perhaps somewhat remote — that the 
platinum may be recovered and the thief brought to 
book : Basin marked A (scratched on the side), weight 
2i"877grm8. ; basin scratched B, weight 22'4i2 grms. ; 
basin scratched X, weight 59747 grms. — I am, &c., 

S. Archd. Vasey. 
Liaboratory, 423, Strand, W.C, 
March 17, 1897. 



CHEMICAL 



NOTICES FROM 
SOURCES. 



FOREIGN 



Note.— All degrees of temperature are Centigrade unless otherwise 

expressed. 

Comptes Rendus Hebdomadaires des Seances, del'Academie 
des Sciences. Vol. cxxiv., No. 8, February 22, 1897. 

M. VioUe has been eledted a Member of the Academy 
in the Sedtion of Physics, vice M. Fizeau, deceased. 

M. de Heen, of Liege, addresses to the Academy two 
notes, entitled '* Existence of Anodic Rays analogous to 



Crkuical News, i 
March ig, 1897. J 



Chemical Notices from Foreign Sources. 



143 



the Cathodic Rays," and " Photography of the EleAric 
Radiations of the Sun and of the Solar Atmosphere." 

M. Breton demanded the opening of two sealed papers 
recently deposited by him, and relating, the one to " the 
use of alternating simple currents, diphasic and triphasic, 
for the produdion of X-rays;" and the other to " a radio- 
graphic phial for the refrigeration of the anticathode by a 
current of cold water." 

M. de Sanderval addressed a paper, accompanying 
photographs obtained through metallic plates of different 
natures. 

M. A. Graby, of Malange, sent the description of a 
new photographic procedure, rendering it possible to 
obiain positives in the colours without the produdtion of 
a proof. 

New Method for producing Transparent Crystals. 
— Ch. de Wateville.— If during its growth we give to a 
crystal a movement of rotation on itself it assumes a 
transparency and a lustre analogous to those of precious 
stones seen cut and polished whatever may be the axis of 
the crystal near which the rotation is effedled. The 
movement appears not to lose any influence upon the 
relative development of the faces unless it is very rapid 
and the solution is very concentrated. If we operate, 
e.g., upon a solution of alum saturated above 50° (and 
with the speed of several rotations per second), we pro- 
gressively disappear the faces of the dodecahedron, and 
those of the cube which the crystal presents at the outset 
of the operation ; those of the odahedron of the max- 
imum density alone remaining. The author has obtained 
especially satisfadtory results with potassium and ammo- 
nium alums, copper sulphate, and sodium chlorate. 

On Persulphuryl Chloride. — A. Besson. — This me- 
moir will be inserted in extenso. 

Anethol and its Homologues. — Ch. Mouet and A. 
Chauvet. — The author describes a new synthesis of 
anethol, simpler they consider than than the procedure of 
Perkin. They have thus obtained two homologues of 
anethol (para-butenyl anisol and para-isopentenyl anisol). 

Soluble Oxidising Ferment of the Cassage of 
Wines. — P. Gazeneuve. — Not suitable for useful 
abstradion. 

Deted^ion of Coal-tar Colours in White Wines 
and the Difference between the Colours and those of 
Caramel. — Alb. d'Aguilar and W. da Silva. — This memoir 
will be inserted in full. 

Revue Universelle des Mines et de la Metallurgie. 
Series 3, Vol. xxxvii.. No. i. 
This issue contains no chemical matter. 

No. 2. 
Ores of Manganese in Russia (Chemiker Zeitung). — 
It appears that in 1896 the Russian output of manganese 
ores was 248,000 tons, that of the rest of the world be ng 
only 66,821 tons. 

Bulletin de la Societe d' Encouragement pour F Industrie 
Nationale. Series 5, Vol. ii., No. i. 

Review of the Progress effeded in the Industry o^ 
Essences and Perfumes. — A. Haller. — The author 
claims the produdion of perfumes as an art evidently 
French. Only the English produds approach them in 
fineness, but they possess neither the distindion nor the 
delicacy of French perfumery. France, both on its 
southern coasts and in Algeria, possesses great natural 
advantages for this manufadure; but he recommends 
that the aid of chemical science should be carefully and 
eagerly sought for. He raises the question whether the 
French madder produdion might not have been saved by 
such means, pointing out that, in spite of artificial 
indigo, the yield of India has since 1886 been increased 



from 33.320 chests yearly to 40,510. The firm Schimmel 
and Co., of Leipzig, employs at present nine chemists. 
The English lavender (of Mitcham) cannot be estimated 
solely according to its percentage of linalyle acetate, and 
it is yet preferred to common essences of lavender which 
contain from 30 to 40 per cent. We cannot help expressing 
our deep regret that a part of the precious Mitcham soil 
has been allowed to fall into the hands of "Jerry." 
Whether the oil of lavender obtained at Sandy (Bedford- 
shire) is equal to the Mitcham growth we are not yet able 
to decide. English essence of peppermint (Mitcham) is 
always in demand on account of the fineness of its odour, 
the cause of which chemical research has not yet been 
able to deted. 



MISCELLANEOUS. 

The Chemiker Zeitung. — The issue of February 20th 
gives a plan and a full description of the Pharmaceutical 
Institute and Laboratory for Applied Chemistry in con- 
nedion with the University of Munich. This journal is 
also discussing the possible influence of the deposit of 
" sealed papers " describing the details of an invention 
may have upon a patent subsequently obtained. 

Adion of Nitrogen Oxides upon Ferrous Chloride 
and Bromide. — V. Thomas. — The compounds obtained 
are inalterable in dry air, and undergo no loss of weight 
in a vacuum. In most cases they are capable of being 
split up into chloride (or bromide) and nitrogen peroxide. 
— Comptes Rendus, cxxiv.. No. 8. 

A(!\ion of Dilute Nitric Acid upon Nitrates in 
Presence of Ether. — M. Tanret. — On agitating water 
containing nitric acid with aqueous ether, the acid is dis- 
tributed by the water and the ether so that the quantities 
dissolved by an equal volume of each liquid bear a con- 
stant relation to each other. This relation has been 
called by MM. Berthelot and Jungfleisch the coefficient of 
distribution; it is independent of the relative volume of 
the two liquids, but varies with their temperature and 
concentration. — Comptes Rendus, cxxiv.. No. g. 

Discharge of the Rontgen Rays : Part Played by 
the Surfaces Struck. — Jean Perrin. — The gas effed is 
readily explained if we admit that the X rays at every 
point of their track liberate equal quantities of posi- 
tive and negative eledricity, movable along tubes of 
force which contain them. Similarly the metallic effed 
is readily explained by supposing that on the contad of a 
condudor, and in a manner variable with nature, the ion- 
isation of the gas is very intense. I propose to call this 
phenomenon the superficial ionisation of the gas on con- 
tad wiih the condudor. — Comptes Rendus, cxxiv.. No. 9. 

The Chemical Laboratory of Wiesbaden. — The 
Chemical Laboratory of Prof. Dr. R. Fresenius has been 
attended by fifty-eight Students during the Winter Session 
of 1896-97. Of these, forty-three were from Germany, 
four from England, two from Switzerland, two from 
Sweden and Norway, two from the United States of 
North America, one from Austria, one from Roumania, 
one from Russia, one from Spain, and one from Brazil. 
There were three Assistant Demonstrators in the several 
teaching departments, and twenty Assistants in the 
Versuchsstationen (private laboratories). Besides the 
Diredor, Geh. Hofrath Prof. Dr. R. Fresenius, there are 
engaged, as Teachers in the Establishment, Prof. Dr. H. 
Fresenius, Dr. W. Fresenius, Dr. E. Hintz, Dr. med. G. 
Frank, Dr. W. Lenz.Dr. L.Griinhut, and ArchitedBrahm. 
The next Summer Term begins on the 26th of April. 
Throughout the Winter Session, besides various scientific 
researches, a great number of analy.ses have been under- 
taken in the different departments of the Laboratory for 
manufadurers of all kinds, in judicial cases, and in many 
branches of trade, mining, agriculture, and hygiene. 



144 



Meetings for the Week, 



{Chemical mbws, 
March 19, 1897. 



NOTES AND QUERIES. 

*«* Our Notes and Queries column was opened for the purpose of 
giving and obtaining information likely to be of use to oui readers 
generally. We cannot undertake to let this column be the means 
of transmitting merely private information, or such trade notices 
as should legitimately come in the advertisement columns. 

Dental Alloys.— (Reply to "Jack"). — Consult "Hunter's Me- 
chanical Dentistry" (Longmans and Co., 3s. 6d.). Supplied by Elliot 
Stock, 62, Paternoster Row, E.C., for 3s. id.— G. A. Kbyworth, 
Hastings. 



MEETINGS FOR THE WEEK. 

Monday, 22nd.— Society of Arts, 4.30. (Cantor Leftures). "Alloys," 

by Prof. W. Chandler Roberts-Austen, F.R.S. 
Tuesday, 23rd. — Royal Institution, 3. " Animal Eledtricity," by 

Prof A. D. Waller, F.R.S. 

Wednesday, 24tb.— Society of Arts, 8. "The Transmission of Power 

by Alternating Eledtric Currents," by W. B. 

Esson, M.Inst.C.E. 

Thursday, 25th. — Chemical, 8. Pasteur Memorial Ledturc, by Prof. 

P. F. Frankland, F.R.S. 

Royal Institution, 3. " The Relation of Geology 

to History," Bv Prof. W. Boyd Dawkins, M.A., 
F.R.S., F.G.S. 
^^ Society of Arts, 8. •' The Cultivation and Manu- 

facture of Rhea Fibre," by Thomas Barraclough. 
(This meeting will be held at the Imperial 
Institute). 
Friday, 26th.— Royal Institution, 9. " Early Man in Scotland," by 

Sir William Turner, F.R.S. 
Saturday, 27tb.— Royal Institution, 3. " EleAricity and Electrical 
Vibrations," by Right Hon. Lord Rayleigb, M.A., 
F.R.S. 

AGRICULTURAL CHEMICAL ANALYSIS. 

By H. W. Wiley. Vol. I.. SOILS, 151. Vol. II., 
FERTILIZERS, 8j. Vol. III., AGRICULTURAL 
PRODUCTS, 15J. 

ENGINEERING CHEMISTRY. 

By J. B. Stillman. Cloth, 181. 

THE CHEMISTRY OF DAIRYING. 

By H. Snyder. Cloth, 6j. 

THE CHEMISTRY OF POTTERY. 

By Karl Langenbeck. Cloth, 65. 

DEVELOPMENT OF THE PERIODIC LAW. 

By F. P. Venable. Cloth. loj. 

CHEMISTRY FOR BEGINNERS. 

By Edward Hart. Cloth, 65. 

Circulars on application. 

CHEMICAL PUBLISHING CO. 
Easton, Pa., U.S.A. 

Mr. J. G. LORRAIN, M.I.E.E., M.LM.E, M.S.C.I., 

Fellow of the Chartered Institute of Patent Agents, 

Norfolk House, Norfolk Street, London, W.C. 

" PATENTEE'S HANDBOOK " Post Free on application. 



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CHEMICAL LABORATORY, 

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Director— Prof. R. FRESENIUS, Ph.D. 

. , I Prof.R. FRESENIUS, Ph.D. 

Fracttcal Instruction in the Labora-] Prof H.FRESENIUS, Ph.D. 

tory 1 W. FRESENIUS, Ph.D. 

Ie. HINTZ, Ph.D. 

LECTURES. 

Experimental Chemistry (Inorganic) Prof. H. FRESENIUS, Ph.D. 

It'^cHSry'.'T":: :: :: ::(w.FRESENius,Ph.D. 

Organic Chemistry E. HINTZ, Ph.D. 

Chemical Technology L. GRUNHUT, Ph.D. 

Microscopy, with exercises in Micro- » ^ t um^ nu r. 

scopicwork | W. LENZ, Ph.D. 

( Prof.H. FRESENIUS.Ph.D. 
Chemistry and Analysis oJ Foods .. \ W. FRESENIUS, Ph.D..and 
. IE. HINTZ, Ph.D. 

Praaical ex'erclses'i'n Bacteriology*.'. } ^^- ™*''- °- PRANK. 
Technical Drawing, with exercises . . J. BRAHM. 

The next Session commences on the 26th of April. The Regula- 
tions of the Laboratory and the Syllabus of Leftures will be forwarded 
gratis on application to C. W. Kreidel's Verlag, at Wiesbaden, or to 
the undersigned. 

Prof. R. FRESENIUS, Ph.D. 



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Cbbmical Nbwi, I 
March 26, 1897, | 



Esttmation of Thoria. 



145 



THE CHEMICAL NEWS 

Vol. LXXV., No. 1948. 



ESTIMATION OF THORIA. 

CHEMICAL ANALYSIS OF MONAZITE SAND.* 

By CHARLES GLASER. 

Since the introdudlion of the Auer-Welsbach light, the 
commercial importance of monazite sand has grown 
greatly, and chemists are now asked to determine the 
percentage of true monazite, and especially that of thoria, 
in samples of the sand. This has heretofore been accom- 
plished indiredly ; the quantities of iron, titanium, and 
silica were determined, and the remainder of the material 
calculated as monazite. A sample treated in this manner 
gave the following results: — 

Iron oxide 3'5o per cent 

Titanic acid 467 „ 

Silica 6-40 „ 

Monazite, by difference .. .. 85*43 ,, 



The sample contained i8'38 per cent phosphoric acid, 
which calculated as cerium phosphate (fadtor3-32) equals 
61*10 per cent. 

From analyses printed in Dana's " Mineralogy," it was 
inferred that after elimination of rutile and silica, the 
remainder would be found to consist chiefly of phosphates 
of the cerium group, but this is not true. 

For the determination of the acftual composition of the 
monazite sand in question, it was decided to attempt an 
estimation of each of its components, by means of 
methods to be found in the available literature. As chief 
sources of information, Graham-Otto's " Chemistry " 
and Crookes's " Seledt Methods in Chemical Analysis " 
were used ; due regard was also given to the work which 
has appeared in the chemical journals of recent years. I 
was not able, however, to make an exhaustive examina 
tion of the literature. 

It became evident that no reliable method could be 
worked out until examination had been made of all the 
work which had been done in the field, and it seemed 
necessary to investigate the whole question. In the fol- 
lowing statements of preliminary experiments a large por- 
tion of analytical data has been omitted, because other- 
wise this paper would have been bulky. Only the out- 
lines of a general plan of procedure will therefore be 
given. 

So far as possible, it was my intention to examine all 
the methods proposed for estimation of thoria, but in one 
notable instance this could not be done. In the American 
Chemical jfournal (vol. xvi.) L. M. Dennis and F. L. 
Kortright describe a method for estimation of thoria by 
means of potassium hydronitride, KN3. An attempt to 
work by the method proved a failure in my hands, partly 
because of a mishap while preparing the reagent, only 
enough of which was saved for a single qualitative reac- 
tion ; but chiefly because Mr. Dennis declined, when 
requested, to give me further information. He replied 
that he was not then at liberty to detail his experience, 
" as the potassium hydronitride process is more than an 
analytical one. It is a commercial process for the pre- 
paration of pure thoria, which is, I think, unequalled by 
any of the methods employed by the Welsbach chemists, 
Shapleigh included. Some of them have tried to use the 
method and have failed. I think I know why they failed. 

* From the Journal of the American Chemical Society, vol. xviii., 
No. 9. 



But I do not think it quite fair for them to ask me to heln 
them out of their difficulties. *^ 

Although the publication was made in a scientific 
journal, it seems to have been but a partial statement. 
For which reason criticism is invited and the value of the 
work IS thrown somewhat in doubt. No further attempt 
was made to follow it out. 

By means of fusion with alkali carbonates, an attempt 
was made to separate monazite sand into two parts 
According to Wohler, all titanic acid ought to become 
soluble provided the fusion is made at a suffi- 
ciently high temperature. Therefore a blowpipe was 
used. In later work I employed the highest temperatures 
afforded by a muffle, and for as many as two hours. But 
at no time was more than a fradtion of the titanic acid 
rendered soluble in water. Moreover, Wohler's direcftions 
to pour the fusion upon an iron plate, and afterwards to 
powder it, are not praiflicable because of loss likely to 
ensue. It was found best to let the fusion soak in water 
over night, sometimes even for several days, or until per- 
fedt disintegration resulted. But such a procedure may 
have decreased the solubility of titanic acid in water. 
Phosphoric acid and alumina (and also silica to a large 
extent) were completely dissolved out of the fused mass. 
The portion insoluble in water was rendered soluble by 
the well-known treatment with strong sulphuric acid, and 
also by fusion with acid potassium sulphate. The solu- 
tion thus obtained, after being freed from silica, was 
boiled to separate titanic acid, from four to seven hours 
during the first experiment. Later, after addition of 
sodium sulphite, this was accompanied by saturating with 
hydrogen sulphide, first in the hot and then in the cooled 
solution. This method is preferable to the first. 

After separation of titanic acid and the metals of the 
fifth group, various methods were tried for separation of 
thoria from the other earths. It was found that the solu- 
tion must not be strongly acid when treated with ammo- 
nium oxalate for precipitation of thoria and the metals of 
the cerium group, or traces of thoria will remain in solu- 
tion. It is best to nearly neutralise with ammonia, and 
to precipitate in boiling solution. 

During the earlier experiments some difficulty was 
found in keeping in solution all of the zirconia, which is 
accomplished only by a large excess of the reagent, while 
yttria and glucina readily form soluble double salts. 
Under these conditions oxalates of the cerium metals pre-* 
cipitate immediately, while thorium oxalate separates 
upon cooling. Attempts to separate thorium oxalate 
from oxalates of the metals of the cerium group by filtra- 
tion of the hot solution gave unsatisfadlory results. The 
oxalates will pass through the filter for a long time. 
Bumping of the liquid made it imprafticable to keep it 
boiling until the entire precipitate became crystalline. 
But if large quantities of thoria are to be separated from 
small ones of the other oxalates the method works well. 

After the insoluble oxalates were separated by filtra- 
tion and were washed v/ith water, they were converted 
into oxides by heating, and were re-dissolved as sulphates. 
In this strongly concentrated solution, made nearly 
neutral by ammonia, an attempt was made to separate 
thoria from the other metals by boiling with sodium 
hyposulphite. In no instance was a complete separation 
effedted, but such portions as were obtained proved to be 
quite pure. The single exception was that in which the 
whole of the cerium was precipitated, for reasons not 
ascertained. Attempts were made to free thoria from 
most of the cerium by fradlional precipitation with weak 
ammonia, but no considerable advantage was gained 
thereby, since repeatedly the second fraftion showed 
traces of thorium. 

To determine the solubility or insolubility of the dif- 
ferent substances left in the insoluble residue from 
fusions, such residue was treated with dilute hydrochloric 
acid, both cold and hot. The solution was found to 
contain all the iron and titanium, the larger part of the 
ilica, and about one-half of the earths present ; these 



146 



Estimation of Thoria. 



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Chciiical Nbwb, 1 
March 26, 1897. i 



London Wattr Supply. 



147 



consisted of relatively large portions of zirconia and 
glucina. Thoria seems not to enter into solution, but is 
left with the remainder of the earths. 

An attempt was made to separate thorium oxalate from 
the mixed precipitatedoxalates, by boiling with ammonium 
oxalate. Such boiling, filtering, and crystallising yielded 
oxalates, which, after ignition, corresponded to 2*29 per 
cent of oxides. The earths were, however, of a deep 
orange colour, and contained both cerium and zirconia. 
The latter was present because an insufficient quantity 
of ammonium oxalate had been used in the first precipita- 
tion. In the oxalates of the cerium metals found in- 
soluble in the above treatment, the presence of thoria 
could be distinctly proven by means of sodium hypo- 
sulphite, for which reason the work proved unsatisfaftory. 

To facilitate a comparison of the more important reac- 
tions of the elements herein studied, the accompanying 
table has been prepared partly from their known behaviour, 
and partly from the results obtained during this investi- 
gation. 

With the view of obtaining further knowledge of the 
behaviour of thoria, fragments of Welsbach mantles were 
subjedled to analysis. They weighed o*659i grm., which 
after ignition fell to 0*6552 grm. Prolonged treatment 
with boiling sulphuric acid left a residue of o'oSSj grm., 
which became soluble in water after fusion with acid 
potassium sulphate. The solutions thus obtained were 
examined by the same method, but separately, as fol- 
lows :— After neutralising with ammonia the greater part 
of the free acid, the solutions were heated to boiling and 
hot solution of ammonium oxalate was added. 

In solution I. a precipitate appeared, but dissolved 
rapidly upon addition of more of the reagent. 

In solution II. a slight turbidity appealed, there was no 
precipitate, and it soon became perfedly clear. 

Upon cooling, solution I. yielded a moderate quantity 
of a crystalline deposit, while solution II. gave a copious 
one. Both precipitates were collefted on one filter, 
washed, ignited, and weighed. They yielded 0-1124 grm. 
of thoria. 

The filtrate from I. gave a copious precipitate with 
ammonia, while that from II. gave only a slight one ; both 
of these were washed on one filter, re-dissolved in dilute 
hydrochloric acid, and again precipitated by ammonia. 
An excess of ammonium carbonate entirely dissolved the 
precipitate. Potassium hydroxide gave a precipitate not 
soluble in an excess of the precipitant, indicating zirconia, 
the weight of which was o'SsSo grm. An attempt to 
purify it from occluded alkali, by again precipitating with 
ammonia, failed through an accident, in which part of 
the mnterial was lost. Calculating by difference, the 
weight of zirconia ought to have been 0*5428 grm. Both 
precipitates were pure white. 

Therefore, this analysis afforded the following com- 
position of the mantles :— Thoria, 1715 per cent ; zirconia, 
82 85 per cent. 

The separation of the two earths was effedled without 
difficulty, and the thoria was used in the following experi- 
ments : — 

o'0487 grm. was weighed, dissolved, and mixed with the 
solution of cerium metals from a previous experiment. 
The solution was nearly neutralised with ammonia, 
heated to boiling, a hot solution of ammonium oxalate 
added, and the mixture allowed to cool. The precipitate 
was caught on a filter and washed with cold water, ex- 
tradled in boiling ammonium oxalate solution, caught on 
a filter, and washed hot ; the filtrate was allowed to cool 
(precipitate i). The residue was macerated in a hot so- 
lution of ammonium acetate, filtered (residue A), and 
filtrate examined for thoria, as follows : — Hydrochloric 
acid was added to separate thoria as oxalate, which fell 
in part only, and the remainder was obtained by sodium 
hydroxide (precipitate 2). Both these precipitates afforded 
but a part of the thoria originally weighed, the greater 
part being held yet with the cerium metals. The method 
had failed. 



The residue (A) upon the filter was reduced to oxide 
and dissolved as sulphate. After neutralising with am- 
monia, the liquid was heated to boiling, and there was 
added an excess of ammonium oxalate with some ammo- 
nium acetate ; after filtering, the filtrate was treated with 
sodium hydroxide (precipitates). 

The precipitates, thus obtained in three fradlions, were 
ignited and found to weigh 0*0774 grm., showing that the 
thoria was very impure. The greyish mass was fused 
with acid potassium sulphate, and unfortunately a small 
fradlion of the fused mass was lost. However, from the 
saved portion a pure thoria, weighing 0*0402 grm., was 
obtained. 

In the next experiment, 0*0343 gr™' of thoria and 
0*1004 grm. of impure cerium oxide were dissolved as 
sulphates, and treated with ammonium oxalate and 
acetate, as for precipitate 3, next above. By precipitating 
the filtrate with ammonia there was obtained 0*0360 grm. 
of impure thoria, which after purification weighed 0*0344 
grm. Cerium oxide recovered weighed 0*0935 g^m. 

I desire to call attention to what has been observed 
frequently during these experiments. If thorium oxalate, 
held in solution by ammonium acetate, b& precipitated by 
ammonia, the earth so obtained, when washed with the 
greatest care and re-dissolved in a mineral acid, cannot 
from an almost neutral solution be again completely pre- 
cipitated by ammonium oxalate; even if the earth had 
been ignited after re-solution. It will also be found that a 
considerable increase has occurred in its solubility in 
liquidscontaining much potastium or ammonium sulphate. 
When enough thoria has been c jllefled, it is my intention 
to further examine this peculiar behaviour. 

(To be continued). 



LONDON WATER SUPPLY. 
Report on the Composition and Quality of Daily 
Samples of the Water Supplied to London 
FOR THE Month Ending February 28th, 1897. 

By WILLIAM CROOKES, F.R.S.. 

and 

PROFESSOR DEWAR, F.R.S. 

To Major-General A. De Courcy Scott, R.E., 
Water Examiner, Metropolis Water Act, 1871. 

London, March loth, 1897. 
Sir, — We submit herewith, at the request of the 
Diredors, the results of our analyses of the 168 samples 
of water colleded 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 Feb. ist to Feb. 28th 
inclusive. The purity of the water, in respedl to organic 
matter, has been determined by the Oxygen and Com- 
bustion processes; and the results of our analyses by 
these methods are stated in Columns XIV. to XVIII. 

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

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

Of the 168 samples examined one was recorded as 
" clear but dull," the remainder being clear, bright, and 
well filtered. 

The rainfall at Oxford during February was 2*41 inches. 
The average for thirty years being 1*76 inches, we have 
had an excess of 065 inch ; 1*48 inches fell on the first 
five days of the month. 

Our badleriological examination of the London watera 
give the following results — 



148 



Revision of the Atomic Weight of Magnesium. 



f Chbuical Nbwb, 
1 March 26, 1807. 



Microbes 
per c.c. 
Thames water, unfiltered (average of 20 

samples) 95^° 

Thames water, from the clear water wells of 
five Thames-derived supplies (average of 99 

samples) 22 

Ditto ditto highest 89 

Ditto ditto lowest 3 

New River, unfiltered (average of 19 samples) 1589 
New River, from the Company's clear water 

well (average of 20 samples) 20 

River Lea, unfiltered (average of 19 samples) 1177 
River Lea, from the East London Water Com- 
pany's clear water well (average of 19 sam- 
ples) 40 

The quality of the London waters during February has 
been uniformly good, with one exception. Since the 
beginning of this year we have much enlarged the scope 
of our enquiries, and have examined badteriologically the 
clear water well at the Hampton Works of the Grand 
Jundlion Water Company, as well as that at the Kew 
Works of the same Company. On some occasions during 
the month the Hampton water has given high results ; 
these were at once communicated to the Engineer of the 
Companyi and the matter is receiving serious attention. 
We are, Sir, 

Your obedient Servants, 

William Crookes. 
James Dewar. 



A REVISION OF THE ATOMIC WEIGHT OF 
MAGNESIUM.' 

By THEODORE WILLIAM RICHARDS 

and 

HARRY GEORGE PARKER. 

Although numerous determinations of the atomic weight 
of magnesium have been made, the results obtained show 
such very wide variations among themselves that the value 
in use at present cannot be accepted with any certainty. 
It will not be necessary to review in detail all the work 
published, as most of it was done more than forty years 
ago, before quantitative methods had attained their present 
exadness ; but the following table of methods used and 
results obtained will assist in a clear comprehension of the 
situation. 

Previous Work on the Atomic Weight of Magnesium.] 
Synthesis of sulphate by the adlion ot sulphuric 
acid on the oxide. 
Berzelius, 1826. " Lehrbuch," 5th edition, iii., 

1227. 25-3 

Svanberg and Nordenfeldt, 1848. Erdmann's 

yourn, Prakt. Chem., 1848, xlv., 473. 24*7 

Bahr, 1852. Erdmann's yourn, Prakt. Chem., 

1852, Ivi., 3x0. 24-8 

Marignac, 1884. Ann. Chim. Phys., 1884, (5)i 

i., 289, 321. 24-37 

Conversion of sulphate into oxide. 

Jacquelain, 1851. Ann. Chim. Phys., (3), kkxu., 

195- 34-5 

Determination of sulphuric acid in sulphate. 

Gay-Lussac, 1820. Ann. Chim. Phys., xiii., 

308. 24-6 

Scheerer, 1846, Pugg. Ann., 1846, Ixix., 535. 24*5 
Scheerer, 1847, Later Correiftion. Pogg. Ann , 

1847, '"" . 407- 24-5 ? 

Jacquelain, 1851. Ann. Chim. Phys., 1851, (3), 

xxxii., 195. 24*2 

♦ Contributions from the Chemical Laboratory of Harvard Coilege. 
From ihe trocee^.ings of the American Academy 0/ Ar sand Sciences, 
vol. xxxii., No. 2. 

t We are indebted to Mr. F. W. Clarke for most of the above 
references. 



Conversion of oxalate into oxide. 

Svanberg ^nd Nordenfeldt, 1848. Erdmann's 

yourn. Prakt. Chem., 1848, xlv., 473. 247 

Determination of chlorine in magnesic chloride. 
Dumas, 1859. Ann. Chim. Phys., 1859, (3), Iv., 

129, 187. 24-6 

Conversion of carbonate into the oxide. 

Marchand and Scheerer, 1850. Erdmann's 

yourn, Prakt. Chem., 1850, 1., 385. 24*0 

Scheerer, 1859, Later Correction. Liebig's 

Ann., 1859, ex., 236. 24*0 

Conversion of metal into oxide. 

Burton and Vorce, 1890. Am. Chem. yourn., 

1890, xii., 219. 24*29 

It will be seen that, with the exception of the results 
obtained by the precipitation of the sulphuric acid with 
barium chloride and the precipitation of the chlorine with 
argentic nitrate, all the methods employed involve the use 
of magnesic oxide. The fadl that all such results are 
untrustworthy was shown by T. W. Richards and E. F. 
Rogers {Proc. Amer. Acad., xxviii., 200J in their work upon 
the occlusion of gases by the oxides of certain metals when 
obtained by the ignition of various salts. The error from 
this source is so large that it seems hopeless to apply a 
corre<5tion to previous work upon the atomic weight of 
magnesium, as the amount of gas occluded depends in a 
large degree upon the method and thoroughness of 
ignition. 

Concerning the results obtained by the precipitation of 
the sulphuric acid in magnesic sulphate, it is only neces- 
sary to point out the error due to the occlusion of various 
soluble substances present in the solution from which the 
precipitation was made. This error was recognised by 
Scheerer, after publishing his results, and an approximate 
correction was made ; but such a corredion does not merit 
much confidence, as will be seen. 

In the work of Dumas it is evident that some magnesic 
oxychloride was formed, and he does not appear at all 
confident of the accuracy of his results. From the experi- 
ence of the writers it does not seem likely that the method 
which he used would give magnesic chloride free from 
the oxide. 

Preliminary Experiments. 

Because considerable experience had been gained in a 
previous research {Proc. Amer. Acad. Arts Sci., xxxi., p. 
by) upon the occlusion by baric sulphate of salts present 
in a solution from which this insoluble salt was precipi- 
tated, it was thought that Gay-Lussac's and Scheerer's 
method of precipitating magnesic sulphate with baric 
chloride might now be used with advantage, applying 
subsequently the necessary correcflions for occluded sub- 
stances. It had previously been found that the concen- 
tration of the solution and the method of pouring had a 
great deal to do with the amount of occlusion ; and hence 
it seemed likely that by working in a very dilute solution 
and pouring the magnesic sulphate into the baric chloride 
with extreme slowness, the occlusion of baric chloride 
might be large, but that the precipitate might be free from 
magnesium. Several experiments were made to ascertain 
the corredness of this supposition, but in each case it was 
found that, notwithstanding the precautions adopted, a 
very notable quantity of magnesium was occluded in the 
baric sulphate. It had been the custom in working upon 
this precipitation to fuse the weighed baric sulphate with 
sodic carbonate, to extrad the sodic chloride thus formed, 
and to determine the chlorine with argentic nitrate and 
calculate as baric chloride, subtradting this amount from 
the total weight of baric sulphate found. This method 
gave very satisfadlory results, but of course it could not 
be applied when the baric sulphate was mixed with 
magnesic chloride and sulphate as well as baric chloride, 
for then no one could discover the proportion in which 
each salt was present with sufficient accuracy for work 
upon atomic weights. 



Crbmical Nbws, I 
March 26, 1897. I 



Revision of the A tomic Weight of Magnesium^ 



149 



The possibility of obtaining satisfatSlory results by the 
determination of the chlorine in magnesic chloride was 
now considered. The great disadvantage of this method, 
as is well known, is the extreme difficulty of obtaining 
pure anhydrous magnesic chloride. The usual method of 
igniting the double chloride of ammonium and magnesium 
was tried a number of times, but it was found that a 
quantity of the oxychloride was always formed. As indi- 
cators do not give a sharp reaction in the presence of 
magnesic salts, the hydrochloric acid driven off cannot be 
added afterwards by titrating back to the neutral point 
with a weak acid solution, and it is therefore necessary to 
obtain in the first place magnesic chloride containing its 
full complement of acid. 

The method was then modified by condudling the 
ignition of the double salt in a tightly covered platinum 
crucible in a stream of hydrochloric acid instead of air. 
That a considerable quantity of oxychloride was usually 
formed, even under these conditions, was easily ascer- 
tained by dissolving the resulting produdt in water, when 
the oxychloride remained as an insoluble residue. In two 
or three cases, however, the amount of oxychloride formed 
was comparatively small ; hence it was hoped that, if the 
right conditions could be found, the chloride might be ob- 
tained in a pure state. Another series of experiments 
with a modified apparatus was therefore undertaken. 



result the hard glass tube was ground with a long tapering 
joint diredtly into the wider desiccating or cooling tube 
used to contain the weighing bottle. This desiccating- 
tube had a sort of bulb or *' pocket " blown upon one side 
of it, to receive the stopper of the weighing-bottle, thus 
allowing the boat to be pushed past the stopper dire(5ily 
from the ignition-tube into the bottle. Afterwards the 
stopper could be rolled into place with a rod provided for 
the purpose. The arrangement was used with great suc- 
cess in a recent determination of the atomic weight of 
zinc (Richards and Rogers, Pvoc. Amer. Acad., xxxi., 158, 
174), to which it was equally applicable. A reference to 
the annexed sketch (Fig. i) will make the apparatus more 
comprehensible. 

The desiccating apparatus for the hydrochloric acid gas 
consisted of two towers, composed of a number of glass 
bulbs filled with beads, upon which strong sulphuric acid was 
allowed to trickle from small reservoirs at the top into 
suitable receptacles at the bottom. This apparatus was 
construfled wholly of glass, with glass gridirons for 
flexibility, and ground or sealed glass connedtions. Joints 
were made tight with syrupy phosphoric acid (Morley). 
The hydrochloric acid, after being evolved by allowing 
strong sulphuric acid to run into a flask containing a 
strong solution of hydrochloric acid, was passed through 
a wash-bottle containing sulphuric acid, thence through 




Fig. I.— Bottling Apparatus, Horizontal Section. 
B, stopper of bottle. C C, hard glass tube. D, platinum boat containing fused magnesic chloride. 



A, weighing-bottle 

The expulsion of the ammonic chloride was conduced in 
a combustion-tube and the number of drying-tubes was 
increased, so that the hydrochloric acid gas might be as 
free as possible from water. The heat was applied very 
gradually, in order that the double chloride might be 
almost anhydrous before the sublimation of the ammonic 
chloride began. This method gave better results. It was 
observed that in two or three experiments, where the con- 
ditions had been unusually favourable, the resulting 
chloride gave a clear solution ; and it seemed therefore 
probable that, if an apparatus could be devised to deliver 
a rapid stream of hydrochloric acid gas entirely free from 
aqueous vapour, the method might be successful. 

Assuming that these conditions might be fulfilled, 
another difficulty remained to be overcome ; for everi if 
the magnesic chloride could be obtained in the combustion 
tube free from water and oxychloride, the problem still 
remained to weigh the salt without foreign admixture. If 
the boat were allowed to remain in the tube until cool, 
and then removed to a weighing-bottle, the salt must ab- 
sorb a very notable quantity of moisture from the air in 
the operation, however quickly this operation might be 
performed. The boat cannot be transferred to another 
tube and re-heated, as the moisture present readts upon 
the chloride, forming some oxychloride and liberating 
hydrochloric acid. If it is taken from the combustion- 
tube while hot and allowed to cool in a weighing bottle, 
the same effeft is produced. Dumas had met with the 
same difficulties in his work with this method, and he 
endeavoured to compromise matters by removing the boat 
from the combustion - tube when it had only partly 
cooled. As his subsequent results proved, however, the 
moisture from the air reaped upon the chloride, forming 
some oxychloride, which interfered seriously with the 
accuracy of his work. To obviate this difficulty the form 
of apparatus used by one of us (Richards, Proc. Amer. 
Acad., XXX., 383) in drying strontic bromide was altered 
80 that the boat could be transferred diredlly from the 
ignition-tube to the weighing-bottle without an instant^s 
exposure to the outside air. In order tc accomplish this 



the towers just described, afterwards through a tube con- 
taining phosphoric pentoxide, and finally into the com- 
bustion tube. The apparatus was so arranged that the 
current of air from an aspirator could be passed through 
another set of towers, a duplicate of those used for drying 
the acid gas. By means of stopcocks either dry hydro- 
chloric acid gas or dry air could be passed through the 
tube containing the weighing tube and boat. 

With the help of this contrivance it was found possible 
to drive off the ammonic chloride in a current of dry 
hydrochloric acid, to drive off the excess of acid from the 
fused magnesic chloride by means of a current of perfedly 
dry air, and to shut up the pure salt in a weighing-bottle 
without the least possible means of access of a trace of 
aqueous vapour. The details of the method will be 
described later; magnesic chloride prepared after this 
fashion gives a perfe&Iy clear solution in water. Since 
this problem was solved, attention was now turned to the 
preparation of materials for the atomic weight determina- 
tions. 

(To be continued). 



Industrial Transformation of Olei'c Acid into 
StearolaAone and Monooxystearic Acid. — M. David. 
— The author can form at will stereoladlone and oxystearic