Chapter 2

When oil ceases to flow, tepid water is poured upon the bags to carry off oil retained by the bags. The pulp is then removed from the bags, ground again in the mill, then replaced in the bags, and pressed a second time. The water used in the process of making oil must be quite pure; the mill, press, bags, and vessels sweet and clean, as the least taint would ruin the quality of the oil produced.

The oil which has collected in the tank or receptacle just mentioned is removed day by day, and the water also drained off, as oil would suffer in quality if left in contact with water; the water also, which necessarily contains some oil mingled with it, is sent to a deposit outside, and at some distance from the crushing house, which is called the "Inferno," where it is allowed to accumulate, and the oil which comes to the surface is skimmed off from time to time. It is fit only for manufacturing purposes.

After the second pressing the olive-pulp is not yet done with; it is beaten up with water by mechanical agitators moved by water-power, and then the whole discharged into open-air tanks adjoining the crushing house. There the crushed olive kernels sink to the bottom, are gathered up and sold for fuel, fetching about 12 francs per 1,000 kilos, while the _debris_ of the pulp is skimmed off the surface of the tank and again pressed in bags, yielding a considerable quantity of inferior oil, called "olio lavato," or washed oil, which, if freshly made, is even used for food by the poorer classes. The pulp then remaining has still further use. It is sold for treatment in factories by the sulphide of carbon process, and by this method yields from seven to nine per cent. of oil, of course suitable only for manufacturing purposes. Only the first two pressings yield oil which ranks as first quality, subject of course to the condition of the fruit being unexceptionable. New oil is allowed to rest a while in order to get rid of sediment; it is then clarified by passing through clean cotton wool, when it is fit for use.

The highest quality of olive oil for eating purposes should not only be free from the least taint in taste or smell, but possessed of a delicate, appetizing flavor. When so many favorable conditions are needed as to growth, maturity, and soundness of the fruit, coupled with great attention during the process of oil-making, it is not to be wondered at that by no means all or even the greater part of the oil produced in the most favored districts of Tuscany is of the highest quality. On the contrary, the bulk is inferior and defective.

These defective oils are largely dealt in both for home consumption and export, when price and not quality is the object.

In foreign countries there is always a market for inferior, defective olive oil for cooking purposes, etc., provided the price be low. Price and not quality is the object, so much so that when olive oil is dear, cotton-seed, ground-nut, and other oils are substituted, which bear the same relation to good olive oil that butterine and similar preparations do to real butter.

The very choicest qualities of pure olive oil are largely shipped from Leghorn to England, along with the very lowest qualities, often also adulterated.

The oil put into Florence flasks is of the latter kind. Many years back this was not the case, but now it is a recognized fact that nothing but the lowest quality of oil is put into these flasks; oil utterly unfit for food, and so bad that it is a mystery to what use it is applied in England. Importers in England of oil in these flasks care nothing, however, about quality; cheapness is the only desideratum.

The best quality of Tuscan olive oil is imported in London in casks, bottled there, and bears the name of the importers alone on the label. There is no difficulty in procuring in England the best Tuscan oil, which nothing produced elsewhere can surpass; but consumers who wish to get, and are willing to pay for, the best article must look to the name and reputation of the importers and the general excellence of all the articles they sell, which is the best guarantee they can have of quality.

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BEESWAX AND ITS ADULTERATIONS.

Beeswax is a peculiar waxy substance secreted only by bees, and consisting of 80.2 per cent. carbon, 13.4 per cent. hydrogen, and 6.4 per cent. oxygen. It is a mixture of myricine, cerotic acid, and cerolein, the first of which is insoluble in boiling alcohol, the second is soluble in hot alcohol and crystallizes out on cooling, while the third remains dissolved in cold alcohol.

Although we are unable to produce real beeswax artificially, there are many imitations which are made use of to adulterate the genuine article, and their detection is a matter of considerable difficulty. Huebl says (_Dingl. Jour._, p. 338) that the most reliable method of estimating the adulteration of beeswax is that proposed by Becker, and known as the saponification method.

The quantity of potassic hydrate required to saponify one gramme or 15 grains of pure beeswax varies from 97 to 107 milligrammes. Other kinds of wax and its substitutes require in some cases more and in others less of the alkali. This method would, however, lead to very erroneous conclusions if applied to a mixture of which some of the constituents have higher saponification numbers than beeswax and others higher, as one error would balance the other.

To avoid this, the quantity of alkali required to saponify the myricine is first ascertained, and then that required to saturate the free cerotic acid. In this way two numbers are obtained; and in an investigation of twenty samples of Austrian yellow beeswax, the author found these numbers stood to each other almost in the constant ratio of 1 to 3.70. Although this ratio cannot be considered as definitely established by so few experiments, it may serve as a guide in judging of the purity of beeswax.

The experiment is carried out as follows: 3 or 4 grammes of the wax that has been melted in water are put in 20 c.c. of neutral 95 per cent, alcohol, and warmed until the wax melts, when phenolphthaleine is added, and enough of an alcoholic solution of potash run in from a burette until on shaking it retains a faint but permanent red color. The burette used by the author is divided in 0.05 c.c. After adding 20 c.c. more of a half normal potash solution, it is heated on a water bath for ¾ hour. Then the uncombined excess of alkali is titrated with half normal hydrochloric acid. The alcohol must be tested as to its reaction before using it, and carefully neutralized with the acid of phenolphthalein.

To saturate the free acid in 1 gramme of wax requires 19 to 21 milligrammes of potassic hydrate, while 73 to 76 milligrammes more are necessary to saponify the myricine ether. The lower numbers in the one usually occur with low numbers for the other, so that the proportions remain 1 to 3.6 or 1 to 3.8.

For comparison he gives the following numbers obtained with one gramme of the more common adulterants:

+----------+----------+---------+--------+ | To | To | Total | | |neutralize| convert |saponifi-| | | the acid.|the ether.| cation. | Ratio. | ----------------+----------+----------+---------+--------+ Japanese wax | 20 | 200 | 220 | 10 | Carnauba wax | 4 | 75 | 79 | 19 | Tallow | 4 | 176 | 180 | 44 | Stearic acid | 195 | 0 | 195 | 0/195 | Rosin | 110 | 1.6 | 112 | 0.015 | Paraffine | 0 | 0 | 0 | 0 | Ceresine | 0 | 0 | 0 | 0 | Yellow beeswax | 20 | 75 | 95 | 3.75 | ----------------+----------+----------+---------+--------+

The author deduces the following conclusions as the results of these investigations:

1. If the numbers obtained lie between these limits, 19 to 21, 73 to 76, 92 to 97, and 3.6 to 3.8 respectively, it may be assumed that the beeswax is pure, provided it also corresponds to beeswax in its physical properties.

2. If the saponification figures fall below 92 and yet the ratio is correct, it is adulterated with some neutral substance like paraffine.

3. If the ratio is above 3.8, it is very probable that Japanese or carnauba wax or grease has been added.

4. If the ratio falls below 3.6, stearic acid or resin has been used as the adulterant.

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PHENOL IN THE STEM, LEAVES, AND CONES OF PINUS SYLVESTRIS.

A DISCOVERY BEARING ON THE FLORA OF THE CARBONIFEROUS EPOCH AND THE FORMATION OF PETROLEUM.

By A.B. GRIFFITHS, Ph.D., F.C.S. Membre de la Societe Chimique de Paris, Medallist in Chemistry and Botany, etc.

Having found, in small quantities, alcohols of the C_{n}H_{2n-7} series, last summer, in the stem, acicular leaves, and cones of _Pinus sylvestris_, I wish in this paper to say a few words on the subject.

First of all, I took a number of cones, cut them up into small pieces, and placed them in a large glass beaker, then nearly filled it with distilled water, and heated to about 80° C., keeping the decoction at this temperature for about half an hour, I occasionally stirred with a glass rod, and then allowed it to cool, and filtered. This filtrate was then evaporated nearly to dryness, when a small quantity of six-sided prisms crystallized out, which subsequently were found to be the hydrate of phenol (C_{6}H_{5}HO)_{2}H_{2}O. Its melting point was found to be 17.2° C. Further, the crystals already referred to were dissolved in ether, and then allowed to evaporate, when long colorless needles were obtained, which, on being placed in a dry test tube and the tube placed in a water bath kept at 42° C., were found to melt; and on making a careful combustion analysis of these crystals, the following composition was obtained:

Carbon 76.6 Hydrogen 6.4 Oxygen 17.0 ----- 100.0

This gives C_{6}H_{6}O, which is the formula for phenol.

On dissolving some of these crystals in water (excess) and adding ferric chloride, a beautiful violet color was imparted to the solution. To another aqueous solution of the crystals was added bromine water, and a white precipitate was obtained, consisting of tribromophenol. An aqueous solution of the crystals immediately coagulated albumen.

All these reactions show that the phenol occurs in the free state in the cones of this plant. In the same manner I treated the acicular leaves, and portions of the stem separately, both being previously cut up into small pieces, and from both I obtained phenol.

I have ascertained the relative amount of phenol in each part of the plant operated upon; by heating the stem with water at 80° C., and filtering, and repeating this operation until the aqueous filtrate gave no violet color with ferric chloride and no white precipitate with bromine water.

I found various quantities according to the age of the stem. The older portions yielding as much as 0.1021 per cent, while the young portions only gave 0.0654 per cent. The leaves yielding according to their age, 0.0936 and 0.0315 per cent.; and the cones also gave varying amounts, according to their maturity, the amounts varying between 0.0774 and 0.0293.

Two methods were used in the quantitative estimation of the amount of phenol. The first was the new volumetric method of M. Chandelon (_Bulletin de la Societe Chemique de Paris_, July 20, 1882; and _Deutsch-Americanishe Apotheker Zeitung_, vol. iii., No. 12, September 1, 1882), which I have found to be very satisfactory. The process depends on the precipitation of phenol by a dilute aqueous solution of bromine as tribromophenol. The second method was to extract, as already staled, a known weight of each part of the plant with water, until the last extract gives _no_ violet color with ferric chloride, and no white precipitate with the bromine test (which is capable of detecting in a solution the 1/60000 part of phenol). The aqueous extract is at this point evaporated, then ether is added, and finally the ethereal solution is allowed to evaporate. The residue (phenol) is weighed directly, and from this the percentage can be ascertained. By this method of extraction, the oil of turpentine, resins, etc., contained in _Pinus sylvestris_ do not pass into solution, because they are insoluble in water, even when boiling; what passes into solution besides phenol is a little tannin, which is practically insoluble in ether.

From this investigation it will be seen that phenol exists in various proportions in the free state in the leaves, stem, and cones of _Pinus sylvestris_, and as this compound is a product in the distillation of coal, and as geologists have to a certain extent direct evidence that the flora of the Carboniferous epoch was essentially crytogamous, the only phænogamous plants which constituted any feature in "the coal forests" being the coniferæ, and as coal is the fossil remains of that gigantic flora which contained phenol, I think my discovery of phenol in the coniferæ of the present day further supports, from a chemical point of view, the views of geologists that the coniferæ existed so far back in the world's history as the Carboniferous age.

I think this discovery also supports the theory that the origin of petroleum in nature is produced by moderate heat on coal or similar matter of a vegetable origin. For we know from the researches of Freund and Pebal (_Ann. Chem. Pharm._, cxv. 19), that petroleum contains phenol and its homologues, and as I have found this organic compound in the coniferæ of to-day, it is probable that petroleum in certain areas has been produced from the conifers and the flora generally of some primæval forests. It is stated by numerous chemists that "petroleum almost always contains solid paraffin" and similar hydrocarbons. Professors Schorlemmer and Thorpe have found heptane in Pinus, which heptane yielded primary heptyl-alcohol, and methyl-pentyl-carbinol, exactly as the heptane obtained from petroleum does (_Annalen de Chemie_, ccxvii., 139, and clxxxviii., 249; and _Berichte der Deutschen Chemischen Gesellschaft_, viii., 1649); and, further, petroleum contains a large number of hydrocarbons which are found in coal. Again, Mendelejeff, Beilstein, and others (_Bulletin de la Societe Chemique de Paris_, No. 1, July 5, 1883), have found hydrocarbons of the--

C_{n}H_{2n2+}, C_{n}H_{2n-6},

also hydrocarbons of the C_{n}H_{2n} series in the petroleum of Baku, American petroleum containing similar hydrocarbons.

I think all these facts give very great weight to the theory that petroleum is of organic origin.

On the other hand, Berthelot, from his synthetic production of hydrocarbons, believes that the interior of the globe contains alkaline metals in the _free_ state, which yield acetylides in the presence of carbonic anhydride, which are decomposed into acetylene by aqueous vapor. But it has been already proved that acetylene may be polymerized, so as to produce aromatic carbides, or the derivatives of marsh gas, by the absorption of hydrogen. Berthelot's view, therefore, is too imaginative; for the presence of _free_ alkaline metals in the earth's interior is an unproved and very improbable hypothesis. Byasson states that petroleum is formed by the action of water, carbonic anhydride, and sulphureted hydrogen upon incandescent iron. Mendelejeff thinks it is formed by the action of aqueous vapor upon carbides of iron; and in his article, "Petroleum, the Light of the Poor" (in this month's--February--number of _Good Words_), Sir Lyon Playfair, K.C.B., F.R.S., etc., holds opinions similar to those of Mendelejeff.

Taking in consideration the facts that solid paraffin is found in petroleum and is also found in coal, and from my own work that phenol exists in _Pinus sylvestris_, and has been found by others in coal which is produced from the decomposition of a flora containing numerous gigantic coniferæ allied to Pinus, and that petroleum contains phenol, and each (i.e., petroleum and coal) contains a number of hydrocarbons common to both, I am inclined to think that the balance of evidence is in favor of the hypothesis that petroleum has been produced in nature from a vegetable source in the interior of the globe. Of course, there can be no practical or direct evidence as to the origin of petroleum; therefore "theories are the only lights with which we can penetrate the obscurity of the unknown, and they are to be valued just as far as they illuminate our path."

In conclusion, I think that there is a connecting link between the old pine and fir forest of bygone ages and the origin of petroleum in nature.--_Chemical News._

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THE SCHOOL OF PHYSICS AND CHEMISTRY OF PARIS.

Recently we paid a visit to the New Municipal School of Physics and Chemistry that the city of Paris founded in 1882, and that is now in operation in the large building of the old Rollin College. This establishment is one of those that supply a long-felt want of our time, and we are happy to make it known to our readers. The object for which it was designed was, in the intention of its founders, to give young people who have just graduated from the higher primary schools special instruction which shall be at once scientific and practical, and which shall fit them to become engineers or superintendents in laboratories connected with chemical and physical industries. To reach such a result it has been necessary to give the teaching an essentially practical character, by permitting the pupils to proceed of themselves in manipulations in well fitted laboratories. It is upon this important point that we shall now more particularly dwell; but, before making known the general mode of teaching, we wish to quote a few passages from the school's official programme:

"Many questions and problems, in physics as well as in chemistry, find their solution only with the aid of mathematics and mechanics. It therefore became necessary, through lectures bearing upon the useful branches of mathematics, to supplement the too limited ideas that pupils brought with them on entering the school. Mathematics and mechanics are therefore taught here at the same time with physics and chemistry, but they are merely regarded in the light of auxiliaries to the latter.

"The studies extend over three years. Each of the three divisions (1st, 2d, and 3d years) includes thirty pupils.

"During the three first semesters, pupils of the same grade attend lectures and go through manipulations in chemistry, physics, mathematics, and draughting in common.

"At the end of the third semester they are divided into 10 physical and 20 chemical students.

"From this moment, although certain courses still remain wholly or partially common to the two categories of pupils (physical and chemical), the same is no longer the case with regard to the practical exercises, for the physical students thereafter manipulate only in the physical laboratories, and the chemical only in the chemical laboratories; moreover, the manipulations acquire a greater importance through the time that is devoted to them.

"At each promotion the three first semesters are taken up with general and scientific studies. Technical applications are the subject of the lectures and exercises of the three last semesters. At the end of the third year certificates are given to those pupils who have undergone examination in a satisfactory manner, and diplomas to such as have particularly distinguished themselves."

When pupils have been received at the school, after passing the necessary examination, their time of working is divided up between lectures and questionings and different laboratory manipulations.

The course of lectures on general and applied physics comprises hydrostatics and heat (Prof. Dommer), electricity and magnetism (Prof. Hospitalier), and optics and acoustics (Prof. Baille). Lectures on general chemistry are delivered by Profs. Schultzenberger and Henninger, on analytical chemistry by Prof. Silva, on chemistry applied to the industries by Prof. Henninger (for inorganic) and Prof. Schultzenberger (for organic). The lectures on pure and applied mathematics and mechanics are delivered by Profs. Levy and Roze.

The pupils occupy themselves regularly every day, during half the time spent at the school, with practical work in analytical and applied chemistry and physics and general chemistry. This practical work is a complement to the various lectures, and has reference to what has been taught therein. Once or twice per week the pupils spend three hours in a shop devoted to wood and metal working, and learn how to turn, forge, file, adjust, etc.

The school's cabinets are now provided with the best instruments for study, and are daily becoming richer therein. The chemical laboratories are none the less remarkably organized. In the accompanying cut we give a view of one of these--the one that is under the direction of Mr. Schultzenberger, professor of chemistry and director of the new school. Each pupil has his own place in front of a large table provided with a stand whereon he may arrange all the products that he has to employ. Beneath the work-table he has at his disposal a closet in which to place his apparatus after he is through using them. Each pupil has in front of him a water-faucet, which is fixed to a vertical column and placed over a sink. Alongside of this faucet there is a double gas burner, which may be connected with furnaces and heating apparatus by means of rubber tubing. A special hall, with draught and ventilation, is set apart for precipitations by sulphureted hydrogen and the preparation of chlorine and other ill-smelling and deleterious gases. The great amount of light and space provided secure the best of conditions of hygiene to this fine and vast laboratory, where young people have all the necessary requisites for becoming true chemists.--_La Nature._

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DUST-FREE SPACES.[1]

[Footnote 1: Lecture to the Royal Dublin Society by Dr. Oliver J. Lodge, April 2, 1884.]

Within the last few years a singular interest has arisen in the subject of dust, smoke, and fog, and several scientific researches into the nature and properties of these phenomena have been recently conducted. It so happened that at the time I received a request from the secretary of this society to lecture here this afternoon I was in the middle of a research connected with dust, which I had been carrying on for some months in conjunction with Mr. J.W. Clark, Demonstrator of Physics in University College, Liverpool, and which had led us to some interesting results. It struck me that possibly some sort of account of this investigation might not be unacceptable to a learned body such as this, and accordingly I telegraphed off to Mr. Moss the title of this afternoon's lecture. But now that the time has come for me to approach the subject before you, I find myself conscious of some misgivings, and the misgivings are founded upon this ground: that the subject is not one that lends itself easily to experimental demonstration before an audience. Many of the experiments can only be made on a small scale, and require to be watched closely. However, by help of diagrams and by not confining myself too closely to our special investigation, but dealing somewhat with the wider subject of dust in general, I may hope to render myself and my subject intelligible if not very entertaining.