anh pues on LL N }
34 Hydrogen Peroxide and Ozone. : Rg
2 ————— = Te - 7 ee A —— wae
1ct seem to us a very happy mixture. To the pulverised * cessive level of the juice. Upon testing it I found abun.
slot are added dried human excrement and ground lance of a stannous salt present, which speedily oxidised
+ knoppern ’—an inferior kind of gall-nuts, from which the to stannic when the juice was filtered. There was no
tannin has doubtless been already extra&ted. Why not ‘ead present, but a trace of iron.
use superphosphate ? The author points out that dried Thinking that perhaps the tin was not attacked till it
blood as a plastic material has been superseded by certain was opened, and air had access, I punétured another tin
preparations of cellulose. It may, perhaps, slightly and poured off the juice; but this’ also contained the
nauseate the public to learn that certain admired artificial same metal, and upon opening there was an encrusted
fruit-flavours—such as pineapple ether, apricot-ether, ring where the level of the juice had stood.
strawberry-ether, &c.—derive their origin from the residues Ialso tested the juice from a tin of apricots, and found
of the slaughter-house. . the same contamination, but to a less extent. The juice
The shells of the cacao-bean are recommended as the of the latter was less acid and much thicker with sugar
source of a brown pigment, We fear that in England they than that of the former.—I am, &c.,
gererally find their way into the stomach of the public in A. PERCY SMITH.
the guise of cocoa and chocolate. Rugby, July 8, 1880.
The uses to which iron slags may be put are the pre.
paration of slag-wool, bricks, glass, and certain salts, including
 sulphate of alumina.
Sewage is very slightly touched upon, but one of the
processes of General Scott is described in such a manner
that he appears as having devised the process of treatment
with lime along with salts of iron and aluminium.
Under the title © Utilisation of Waste Matters for the
Production of Colours” we find an account of the so-called
patent dyes of Croissant and Bretonniére, otherwise known
3s “cachon de Lavalle,” These dyes have not proved
very successful, and their manufacture has been abandoned
py several firms who had taken it up.
The brief chapter on the utilisation of the waste-waters
of dye works contains a notice of the patent of 1iiggin and
Stenhouse for recovering arsenic and phosphoric acids,
which have been used in dung-substitutes, and of that of
Remmer’s for precipitating alizarin and purpurin from the
sinsings of Turkey-red works.
In the sedion on treacle and *vinasses” we find a
notice of the recent invention of Camille Vincent, but the
application of the methyl chloride obtained by his process
for the extraction of perfumes from flowers has escaped
mention.
The produ@ion of oxalic acid from the waste of parchment
 paper is regarded as hopeful, since the resulting
crystals will not be contaminated with the colouring
matters which are formed by the action of alkalies upon
the sawdust of hard woods.
Petroleum residues as a source for the produdion of
aniline, alizarine, &c., as shown in the researches of
Lettny, are slightly touched upon.
The various known processes for recovering tin from
inners’ waste are described at consideratle length.
As a whole the work can scarcely be pronounced satisfactory.
 The statements advanced are indeed trusworthy,
and there is little of that confusion which we have met
with in another book on the same subje&. But the various
processes mentioned are, as a rule, described in a slight
and sketchy manner. Much of the information given is
merely obtained from well-known and public sources, such
as the specifications of patents and from such works as
Muspratt’s * Chemistry.” There are few suggestive hints
and very few traces of private and special observation or
inquiry in the various branches of industry concerned.

To the Editor of the Chemical News.
51R,—If the MS. of my last week's letter had been more
egible you would have made me say that ‘the volumes ”
,not *“ the roll ”’) ¢‘ of special class abridgments should all
oe completed up to within a year of date,” by the Patent
Office authorities.
As a practical comment upon this recommendation, it
should be noted that the only volume yet issued of abridge
ments of chemical patents is the one so well known to
and consulted by many of your readers—*‘¢ Abridgments:
Acids, Alkalies, Oxides, and Salts. A.D. 1622—1866."
How invaluable to chemical inventors would have been a
-ontinuous issue of these chemical abridgments indexed
1p to present date!
If my previous letter had not been so long I would have
zone on to show that the large revenue derivable from a
>atent tax, commencing at £I per annum, but increasing
£1 with every year of its twenty-one years’ duration,
would maintain a staff of technical men not only to prepare
 abridgments of British patents, but to ascertain
exadtly what had been patented in foreign countries, the
ibridgments in both cases being issued in a weekly pubication
 fully and continuously indexed to date.
The former weekly publication of indexcd abridgments
sroved the entire practicability of the plan, if the Commissioners
 of Patents would only employ a sufficient
number of experts to prepare the abridgments.—I am, &c.,
FRANK.

To the Editor of the Chemical Ncws.
31r,—Your last issue has made me acquainted with the
further experiments of Prof. A. R. Leeds upon the atmospheric
 oxidation of phosphorus.
Will you allow me to state that, having early in this
year commenced a similar study, I was able to announce
at the meeting of the Chemical Society, on June 3rd last,
the following facts :-——
t. Both ozone and peroxide of hydrogen are formed by
the a&ion of air upon phosphorus in the presence
of water.
The formation of ozone is substantiated by the observations
 that the ative substance in the gas is
destroyed at 300° C., and is totally absorbed bv oil
of turpentine.
The ozone is not decomposed by passing it through
a ro-volume solution of peroxide of hydrogen.
The peroxide of hydrogen produced bears a greater
relation to the ozone formed than stated by Prof.
Leeds, That gentleman estimated the peroxide
“ on the assumption that it is completely absorbed
sy the washing water,” whereas 1 find it chiefly
esides in the water in which the phosphorus is
sxidised.

CORRESPONDENCE.

MN IN PRESERVED FRUITS.

To the Editor of the Chemical News.
31r,—Has tin any action, deleterious or otherwise, when
aken into the human system? I can scaicely imagine
that it is particularly beneficial in large quantities. I
have found that the juice contained in tins of preserved
pine-apple has a very corrosive adion upon the lining of
the containing vessel. I first noticed that, as the contents
were consumed. a ring was formed on the tin at each suc-