Scientific American Supplement No. 275
V >>
Various >> Scientific American Supplement No. 275
Pages:
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 | 11
The President referred to the synthesis of ammonia from its elements
recently effected by Donkin, and remarked that apparently the ammonia was
formed in much larger quantities by the process proposed by the author of
the present paper.
Mr. Warington suggested that some HCl gas should be simultaneously passed
with the nitrogen and hydrogen, and that the temperature of the spongy
platinum should be kept just below the temperature at which NH_3
dissociates, in order to improve the yield of NH_3.
_"On the Oxidation of Organic Matter in Water"_ by A. Downes. The author
considers that the mere presence of oxygen in contact with the organic
matter has but little oxidizing action unless lowly organisms, as bacteria,
etc. be simultaneously present. Sunlight has apparently considerable
effect in promoting the oxidation of organic matter. The author quotes the
following experiment: A sample of river water was filtered through paper.
It required per 10,000 parts 0.236 oxygen as permanganate. A second portion
was placed in a flask plugged with cotton wool, and exposed to sunlight for
a week; it then required 0.200. A third portion after a week, but excluded
from light, required 0.231. A fourth was boiled for five minutes, plugged,
and then exposed to sunlight for a week; required 0.198. In a second
experiment with well water a similar result was obtained; more organic
matter was oxidized when the organisms had been killed by the addition of
sulphuric acid than when the original water was allowed to stand for an
equal length of time. The author also discusses the statement made by Dr.
Frankland that there is less ground for assuming that the organized and
living matter of sewage is oxidized in a flow of twelve miles of a river
than for assuming that dead organic matter is oxidized in a similar
flow.--_Chem. News._
* * * * *
ROSE OIL, OR OTTO OF ROSES.
By CHARLES G. WARNFORD LOCK.
This celebrated perfume is the volatile essential oil distilled from the
flowers of some varieties of rose. The botany of roses appears to be in a
transition and somewhat unsatisfactory state. Thus the otto-yielding rose
is variously styled _Rosa damascena, R. sempervirens, R. moschata, R.
gallica, R. centifolia, R. provincialis_. It is pretty generally agreed
that the kind grown for its otto in Bulgaria in the damask rose (_R.
damascena_), a variety induced by long cultivation, as it is not to be
found wild. It forms a bush, usually three to four feet, but sometimes six
feet high; its flowers are of moderate size, semi-double, and arranged
several on a branch, though not in clusters or bunches. In color, they are
mostly light-red; some few are white, and said to be less productive of
otto.
The utilization of the delicious perfume of the rose was attempted, with
more or less success, long prior to the comparatively modern process of
distilling its essential oil. The early methods chiefly in vogue were the
distillation of rose-water, and the infusion of roses in olive oil, the
latter flourishing in Europe generally down to the last century, and
surviving at the present day in the South of France. The butyraceous oil
produced by the distillation of roses for making rose-water in this country
is valueless as a perfume; and the real otto was scarcely known in British
commerce before the present century.
The profitable cultivation of roses for the preparation of otto is limited
chiefly by climatic conditions. The odoriferous constitutent of the otto
is a liquid containing oxygen, the solid hydrocarbon or stearoptene, with
which it is combined, being absolutely devoid of perfume. The proportion
which this inodorous solid constituents bears to the liquid perfume
increases with the unsuitability of the climate, varying from about 18 per
cent. in Bulgarian oil, to 35 and even 68 per cent. in rose oils distilled
in France and England. This increase in the proportion of stearoptene is
also shown by the progressively heightened fusing-point of rose oils from
different sources: thus, while Bulgarian oil fuses at about 61 deg. to 64 deg.
Fahr., an Indian sample required 68 deg. Fahr.; one from the South of France,
70 deg. to 73 deg. Fahr.; one from Paris, 84 deg. Fahr.; and one obtained in making
rose-water in London, 86 deg. to 891/2 deg. Fahr. Even in the Bulgarian oil, a
notable difference is observed between that produced on the hills and that
from the lowlands.
It is, therefore, not surprising that the culture of roses, and extraction
of their perfume, should have originated in the East. Persia produced
rose-water at an early date, and the town of Nisibin, north-west of Mosul,
was famous for it in the 14th century. Shiraz, in the 17th century,
prepared both rose water and otto, for export to other parts of Persia, as
well as all over India. The Perso-Indian trade in rose oil, which continued
to possess considerable importance in the third quarter of the 18th
century, is declining, and has nearly disappeared; but the shipments of
rose-water still maintain a respectable figure. The value, in rupees, of
the exports of rose-water from Bushire in 1879, were--4,000 to India, 1,500
to Java, 200 to Aden and the Red Sea, 1,000 to Muscat and dependencies, 200
to Arab coast of Persian Gulf and Bahrein, 200 to Persian coast and Mekran,
and 1,000 to Zanzibar. Similar statistics relating to Lingah, in the same
year, show--Otto: 400 to Arab coast of Persian Gulf, and Bahrein; and 250
to Persian coast and Mekran. And Bahrein--Persian Otto: 2,200 to Koweit,
Busrah, and Bagdad. Rose-water: 200 to Arab coast of Persian Gulf, and
1,000 to Koweit, Busrah, and Bagdad.
India itself has a considerable area devoted to rose-gardens, as at
Ghazipur, Lahore, Amritzur, and other places, the kind of rose being _R.
damascena_, according to Brandis. Both rose-water and otto are produced.
The flowers are distilled with double their weight of water in clay stills;
the rose-water (_goolabi pani_) thus obtained is placed in shallow vessels,
covered with moist muslin to keep out dust and flies, and exposed all night
to the cool air, or fanned. In the morning, the film of oil, which has
collected on the top, is skimmed off by a feather, and transferred to a
small phial. This is repeated for several nights, till almost the whole of
the oil has separated. The quantity of the product varies much, and three
different authorities give the following figures: (_a_) 20,000 roses to
make 1 rupee's weight (176 gr.) of otto; (_b_) 200,000 to make the same
weight; (_c_) 1,000 roses afford less than 2 gr. of otto. The color ranges
from green to bright-amber, and reddish. The oil (otto) is the most
carefully bottled; the receptacles are hermetically sealed with wax, and
exposed to the full glare of the sun for several days. Rose water deprived
of otto is esteemed much inferior to that which has not been so treated.
When bottled, it is also exposed to the sun for a fortnight at least.
The Mediterranean countries of Africa enter but feebly into this industry,
and it is a little remarkable that the French have not cultivated it in
Algeria. Egypt's demand for rose-water and rose-vinegar is supplied from
Medinet Fayum, south-west of Cairo. Tunis has also some local reputation
for similar products. Von Maltzan says that the rose there grown for otto
is the dog-rose (_R. canina_), and that it is extremely fragrant, 20 lb.
of the flower yielding about 1 dr. of otto. Genoa occasionally imports a
little of this product, which is of excellent quality. In the south of
France rose gardens occupy a large share of attention, about Grasse,
Cannes, and Nice; they chiefly produce rose-water, much of which is
exported to England. The essence (otto) obtained by the distillation of the
Provence rose (_R. provincialis_) has a characteristic perfume, arising, it
is believed, from the bees transporting the pollen of the orange flowers
into the petals of the roses. The French otto is richer in stearoptene than
the Turkish, nine grammes crystallizing in a liter (13/4 pint) of alcohol at
the same temperature as 18 grammes of the Turkish. The best preparations
are made at Cannes and Grasse. The flowers are not there treated for the
otto, but are submitted to a process of maceration in fat or oil, ten
kilos. of roses being required to impregnate one kilo. of fat. The price of
the roses varies from 50c. to 1 fr. 25c. per kilo.
But the one commercially important source of otto of roses is a
circumscribed patch of ancient Thrace or modern Bulgaria, stretching along
the southern slopes of the central Balkans, and approximately included
between the 25th and 26th degrees of east longitude, and the 42d and 43d of
north latitude. The chief rose-growing districts are Philippopoli, Chirpan,
Giopcu, Karadshah-Dagh, Kojun-Tepe, Eski-Sara, Jeni-Sara, Bazardshik, and
the center and headquarters of the industry, Kazanlik (Kisanlik),
situated in a beautiful undulating plain, in the valley of the Tunja. The
productiveness of the last-mentioned district may be judged from the fact
that, of the 123 Thracian localities carrying on the preparation of otto in
1877--they numbered 140 in 1859--42 belong to it. The only place affording
otto on the northern side of the Balkans is Travina. The geological
formation throughout is syenite, the decomposition of which has provided a
soil so fertile as to need but little manuring. The vegetation, according
to Baur, indicates a climate differing but slightly from that of the Black
Forest, the average summer temperatures being stated at 82 deg. Fahr. at noon,
and 68 deg. Fahr. in the evening. The rose-bushes nourish best and live longest
on sandy, sun-exposed (south and south-east aspect) slopes. The flowers
produced by those growing on inclined ground are dearer and more esteemed
than any raised on level land, being 50 per cent. richer in oil, and that
of a stronger quality. This proves the advantage of thorough drainage. On
the other hand, plantations at high altitudes yield less oil, which is of a
character that readily congeals, from an insufficiency of summer heat. The
districts lying adjacent to and in the mountains are sometimes visited
by hard frosts, which destroy or greatly reduce the crop. Floods also
occasionally do considerable damage. The bushes are attacked at intervals
and in patches by a blight similar to that which injures the vines of the
country.
The bushes are planted in hedge-like rows in gardens and fields, at
convenient distances apart, for the gathering of the crop. They are seldom
manured. The planting takes place in spring and autumn; the flowers attain
perfection in April and May, and the harvest lasts from May till the
beginning of June. The expanded flowers are gathered before sunrise,
often with the calyx attached; such as are not required for immediate
distillation are spread out in cellars, but all are treated within the day
on which they are plucked. Baur states that, if the buds develop slowly,
by reason of cool damp weather, and are not much exposed to sun-heat, when
about to be collected, a rich yield of otto, having a low solidifying
point, is the result, whereas, should the sky be clear and the temperature
high at or shortly before the time of gathering, the product is diminished
and is more easily congealable. Hanbury, on the contrary, when distilling
roses in London, noticed that when they had been collected on fine dry
days the rose-water had most volatile oil floating upon it, and that, when
gathered in cool rainy weather, little or no volatile oil separated.
The flowers are not salted, nor subjected to any other treatment, before
being conveyed in baskets, on the heads of men and women and backs of
animals, to the distilling apparatus. This consists of a tinned-copper
still, erected on a semicircle of bricks, and heated by a wood fire; from
the top passes a straight tin pipe, which obliquely traverses a tub kept
constantly filled with cold water, by a spout, from some convenient
rivulet, and constitutes the condenser. Several such stills are usually
placed together, often beneath the shade of a large tree. The still is
charged with 25 to 50 lb. of roses, not previously deprived of their
calyces, and double the volume of spring water. The distillation is carried
on for about l1/2 hours, the result being simply a very oily rose-water
(_ghyul suyu_). The exhausted flowers are removed from the still, and the
decoction is used for the next distillation, instead of fresh water.
The first distillates from each apparatus are mixed and distilled by
themselves, one-sixth being drawn off; the residue replaces spring water
for subsequent operations. The distillate is received in long-necked
bottles, holding about 11/4 gallon. It is kept in them for a day or two, at a
temperature exceeding 59 deg. Fahr., by which time most of the oil, fluid
and bright, will have reached the surface. It is skimmed off by a small,
long-handled, fine-orificed tin funnel, and is then ready for sale. The
last-run rose-water is extremely fragrant, and is much prized locally for
culinary and medicinal purposes. The quantity and quality of the otto are
much influenced by the character of the water used in distilling. When
hard spring water is employed, the otto is rich in stearoptene, but less
transparent and fragrant. The average quantity of the product is estimated
by Baur at 0.037 to 0.040 per cent.; another authority says that 3,200
kilos. of roses give 1 kilo. of oil.
Pure otto, carefully distilled, is at first colorless, but speedily becomes
yellowish; its specific gravity is 0.87 at 72.5 deg. Fahr.; its boiling-point
is 444 deg. Fahr.; it solidifies at 51.8 deg. to 60.8 deg. Fahr., or still higher; it
is soluble in absolute alcohol, and in acetic acid. The most usual and
reliable tests of the quality of an otto are (1) its odor, (2) its
congealing point, (3) its crystallization. The odor can be judged only
after long experience. A good oil should congeal well in five minutes at
a temperature of 54.5 deg. Fahr.; fraudulent additions lower the congealing
point. The crystals of rose-stearoptene are light, feathery, shining
plates, filling the whole liquid. Almost the only material used for
artificially heightening the apparent proportion of stearoptene is said to
be spermaceti, which is easily recognizable from its liability to settle
down in a solid cake, and from its melting at 122 deg. Fahr., whereas
stearoptene fuses at 91.4 deg. Fahr. Possibly paraffin wax would more easily
escape detection.
The adulterations by means of other essential oils are much more difficult
of discovery, and much more general; in fact, it is said that none of the
Bulgarian otto is completely free from this kind of sophistication. The
oils employed for the purpose are certain of the grass oils (_Andropogon_
and _Cymbopogon spp._) notably that afforded by _Andropogon, Schoenanthus_
called _idris-yaghi_ by the Turks, and commonly known to Europeans as
"geranium oil," though quite distinct from true geranium oil. The addition
is generally made by sprinkling it upon the rose-leaves before distilling.
It is largely produced in the neighborhood of Delhi, and exported to
Turkey by way of Arabia. It is sold by Arabs in Constantinople in large
bladder-shaped tinned-copper vessels, holding about 120 lb. As it is
usually itself adulterated with some fatty oil, it needs to undergo
purification before use. This is effected in the following manner: The
crude oil is repeatedly shaken up with water acidulated with lemon-juice,
from which it is poured off after standing for a day. The washed oil
is placed in shallow saucers, well exposed to sun and air, by which it
gradually loses its objectionable odor. Spring and early summer are the
best seasons for the operation, which occupies two to four weeks, according
to the state of the weather and the quality of the oil. The general
characters of this oil are so similar to those of otto of roses--even the
odor bearing a distant resemblance--that their discrimination when mixed is
a matter of practical impossibility. The ratio of the adulteration varies
from a small figure up to 80 or 90 per cent. The only safeguard against
deception is to pay a fair price, and to deal with firms of good repute,
such as Messrs. Papasoglu, Manoglu & Son, Ihmsen & Co., and Holstein & Co.
in Constantinople.
The otto is put up in squat-shaped flasks of tinned copper, called
_kunkumas_, holding from 1 to 10 lb., and sewn up in white woolen cloths.
Usually their contents are transferred at Constantinople into small gilded
bottles of German manufacture for export. The Bulgarian otto harvest,
during the five years 1867-71, was reckoned to average somewhat below
400,000 _meticals, miskals_, or _midkals_ (of about 3 dwt. troy), or 4,226
lb. av.; that of 1873, which was good, was estimated at 500,000, value
about L700,000. The harvest of 1880 realized more than L1,000,000, though
the roses themselves were not so valuable as in 1876. About 300,000
_meticals_ of otto, valued at L932,077, were exported in 1876 from
Philippopolis, chiefly to France, Australia, America, and Germany.
--_Jour. Soc. of Arts._
* * * * *
A NEW METHOD OF PREPARING METATOLUIDINE.
By OSKAR WIDMAN.
The author adds in small portions five parts metanitro-benzaldehyd to nine
parts of phosphorus pentachloride, avoiding a great rise of temperature.
When the reaction is over, the whole is poured into excess of cold water,
quickly washed a few times with cold water, and dissolved in alcohol. After
the first crystallization the compound melts at 65 deg., and is perfectly pure.
* * * * *
A catalogue, containing brief notices of many important scientific papers
heretofore published in the SUPPLEMENT, may be had gratis at this office.
* * * * *
THE SCIENTIFIC AMERICAN SUPPLEMENT.
PUBLISHED WEEKLY.
TERMS OF SUBSCRIPTION, $5 A YEAR.
Sent by mail, postage prepaid, to subscribers in any part of the United
States or Canada. Six dollars a year, sent, prepaid, to any foreign
country.
All the back numbers of THE SUPPLEMENT, from the commencement, January 1,
1876, can be had. Price, 10 cents each.
All the back volumes of THE SUPPLEMENT can likewise be supplied. Two
volumes are issued yearly. Price of each volume, $2.50, stitched in paper,
or $3.50, bound in stiff covers.
COMBINED RATES--One copy of SCIENTIFIC AMERICAN and one copy of SCIENTIFIC
AMERICAN SUPPLEMENT, one year, postpaid, $7.00.
A liberal discount to booksellers, news agents, and canvassers.
MUNN & CO., PUBLISHERS,
37 PARK ROW, NEW YORK, N. Y.
* * * * *
PATENTS.
In connection with the SCIENTIFIC AMERICAN, Messrs. MUNN & Co. are
Solicitors of American and Foreign Patents, have had 35 years' experience,
and now have the largest establishment in the world. Patents are obtained
on the best terms.
A special notice is made in the SCIENTIFIC AMERICAN of all Inventions
patented through this Agency, with the name and residence of the Patentee.
By the immense circulation thus given, public attention is directed to the
merits of the new patent, and sales or introduction often easily effected.
Any person who has made a new discovery or invention can ascertain, free of
charge, whether a patent can probably be obtained, by writing to MUNN & Co.
We also send free our Hand Book about the Patent Laws, Patents, Caveats.
Trade Marks, their costs, and how procured, with hints for procuring
advances on inventions. Address
MUNN & CO., 37 PARK ROW, NEW YORK.
Branch Office, cor. F and 7th Sts., Washington, D. C.
Pages:
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 | 11