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NEWS

, 1865,

SCIENTIFIC AND ANALYTICAL

CHEMISTRY.

were formed, a few drops of creosote were added to the water intended for washing. Every twenty-four hours the water was decanted and renewed by a fresh supply, under the same conditions. All these washings were

On the Physiological Exhaustion and the Vitality of screened from the air in an atmosphere of carbonic acid,
Beer Yeast, by M. A. BECHAMP.*

THE life of the leaven being contained in the cellule, I supposed that, so long as this cellule was neither destroyed nor dead, the leaven would continue to live, and to manifest this life by its characteristic chemical actions, but in certain cases, such as those about to be described, like an animal in a state of inanition-that is to say, in exhausting itself.

To measure the physiological exhaustion of beer yeast, I estimated the phosphoric acid it eliminates while con suming its own tissues, when forced to live in distilled water.

Mitscherlich analysed beer yeast, and from his analysis concluded that 100 grammes of dry yeast contain the elements of 4.28 gr. of anhydrous phosphoric acid. But this analysis does not prove that the acid was actually

formed there.

the apparatus being in a warm place, the temperature of which could vary from 20 to 30°.

These washings furnished the following results :

1st washing-anhydrous phosphoric acid. 2nd 3rd

4th

gr.

0°056

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These numbers appear significant. Were beer yeast present in the mass, as mother liquor is in a precipitate, merely an inert precipitate, were phosphoric acid The infusion of yeast is, no doubt, always acid, and this soluble matters in the first operations, and the quantity the washings would eliminate the greater part of the acidity may be attributed to phosphoric acid, if the yeast of these matters would diminish more and more. does not ceaselessly engender other acids. To ascertain that we see here that the yeast at first resists, then suddenly the yeast actually contained preformed phosphoric acid, its resistance diminishes, and it yields a large quantity and phosphates, boil the well-washed yeast in a large of its disassimilated materiais. This is ascertained by the quantity of distilled water; this will kill it, and cause it weight of the phosphoric acid eliminated, which sudto abandon various products, and among them phosphoric denly increases to five or six times its previous weight; acid, which estimate by the process presently to be de-after which it naturally decreases. scribed, whence it will be found that 100 grammes of dry yeast disengages from 28 gr. to 31 gr. of phosphoric acid, of which a portion is free.

But though the yeast abandons large quantities of phosphoric acid, at a temperature of 100°, when it is killed, this is not the case when it is left in water, either cold or even heated to 30 or 40°; under these circumstances it abandons the phosphoric acid and other matters very gradually, not as an inert precipitate, but as a living creature, offering vital resistance to destruction. By renewing the water every twenty-four hours, and estimating the phosphoric acid in each lixivium, it will be found that the quantity of this acid, small at first, augments with each successive treatment, and rapidly attains a maximum, after which it decreases, until it altogether disappears. The following is the experiment: In the first place I determined the amount of phosphoric acid which could be found in matters adhering to the yeast, proceeding from the medium in which the yeast was formed, or which had been excreted by the yeast itself and impregnated it externally. 500 grammes of brewers' yeast, new and in a paste, were soaked in cold water and washed on a filter. The yeast having been well drained, there remained four litres of lixivium. In this liquid the phosphoric acid was estimated by the same process which was applied to the following estimations; and there were obtained of anhydrous phosphoric acid, o'095. gr.

This result is invariable; all things being equal, 500 grammes of yeast in a paste, representing about 100 grammes of dry yeast, yield to cold water less than 1 decigramme of phosphoric acid.

280 grammes of this same washed yeast, containing 48.2 gr. of yeast dried at 100°, were introduced into a special apparatus with 1600 cubic centimetres of water boiled and then cooled to 40° in a current of carbonic acid. To make perfectly sure that no foreign bodies

* Comptes Rendus, lxi., 689. YOL. XII. No. 314.-DECEMBER 8, 1865.

By adding the amount of the different estimations at 100 of the phosphoric acid in dry yeast, the number will be found to be 3:38. The weight of phosphoric acid eliminated is then greater by than that produced by the incineration of the yeast, as in Mitscherlich's process; and if it is observed that the yeast eliminates at the same time various other products, proportionately to the quantity of phosphoric acid, an idea may be formed of the degree of exhaustion undergone by each globule. The exhaustion is such that under the microscope the yeast seems reduced to merely its envelope; it is then barely visible, and its colour so faint that it looks like shrivelled skins, with no clear outlines, and with a taste like raspberries. From the nuclei or interior granulations which remain, the form of the envelope may be divined.

If by the use of the apparatus, elsewhere to be described, the air is perfectly excluded, this exhaustion can be effected, without what is called the putrefaction of the yeast, or, more correctly, without the appearance of the organisms which cause the putrefaction of the organic matters eliminated. But if air enters, these products acquire a foetid odour, and there may be observed a disengagement of sulphuretted hydrogen, and the formation of the infusoria, which are the cause of a particular fermentation of the nitrogenised and sulphuretted organic matters of yeast. However, if the other products accompanying phosphoric acid are different, the quantity of the latter in each washing corresponds to the numbers of the above table.

The yeast exhausted in the experiment which furnished the numbers given in the table appeared to be dead; but this was not the case, for it was still capable of transforming cane sugar into glucose-that is to say, of forming zymase and then producing alcohol by the glucose engendered. But the products of alcoholic fermentation by exhausted yeast are notably different in nature and in quantity from those obtained by normal

yeast. The same as in alcoholic fermentation by mother of vinegar, a crystallisable compound is formed possessing the properties of mannite.

These results prove contrary to Mitscherlich (who supposed that the globules of ferment, well washed in water are entirely deprived of the property of saccharifying cane sugar), that yeast continues to change cane sugar until it ceases to live, and that when it is so much exhausted that it may be said to be reduced to its cellule, it nevertheless continues to form successively glucose and alcohol with cane sugar. The property of determining alcoholic fermentation must not, then, be attributed to the catalyic action of some chemical compound which it contains; my researches seem to prove that it is contained in the properties of the living cellule; it is a consequence of the act of nutrition of this cellule.†

Detection of Methylic Alcohol, by Mr. JOHN T. MILLER. THE following modification of my process for the detection of methylic alcohol may be used when it is wished to avoid distillation. It is easy of execution, and gives very fair results :

Prepare in a small flask an oxidising solution with 20 grains of bichromate of potash, fluid drachms of water, and 20 minims of strong sulphuric acid, and add to it 30 minims of the spirit to be tested. After the mixture has stood ten minutes, add just enough milk of lime to give it an alkaline reaction; warm, filter, and wash with half an ounce of warm water. The filtrate will be free from chromic oxide and the greater part of the sulphuric acid. Precipitate the remainder of the latter, and any chromic acid which may be present, by the addition in small excess of a strong solution of acetate of lead; warm slightly, allow a few moments for the precipitate to subside, and filter. The filtrate should now be clear, colourless, and nearly neutral to test-paper. Boil it quickly down to 2 fluid drachms, pour it into an ounce test-tube, add 1 drop of dilute acetic acid (1 part of the B. P. acid to 2 parts water), and 1 grain of nitrate of silver in 30 minims of water; then heat the liquor slowly to the boiling point, and simmer two or three minutes. Darkening of the solution to a con siderable degree may occur even though the spirit be free from methylic alcohol, and is, therefore, a less reliable indication of the presence of that substance than when the oxidation products have been separated by distillation. The state of the test-tube will, however, decide the question. It should be rinsed out, filled with water, and placed against white paper. If it appear clean and uncoloured, the spirit is either pure or contains less than 2 per cent. of methylic alcohol; if, on the other hand, the lower part of the tube have an evident brown tint, the spirit is methylated.

To obtain satisfactory results by this process, the points to be minded are:- 1. To use distilled water. 2. To add only a slight excess of the precipitants. 3. To use a perfectly clean test-tube. 4. To avoid boiling the liquor up the tube, and so thinning the metallic deposit by spreading it over a larger surface.

†These conclusions are opposed to M. Liebig's assertion (Traite de Chimie Organique, introduction p. 27):-"The insoluble body called ferment does not provoke fermentation." The proof he gives of this is, that the yeast washed with water, deprived of air, leaves a residue which has lost the power of fermenting cane sugar. This has caused it erroneously to be supposed that the phenomenon being much less decided had ceased to exist at all. On the other hand, much less attention is given to the previous inversion of the caue sugar, and it is well known (notwithstanding an important and probably unknown experiment of M. Dubrunfant) that M. Pasteur has admitted that cane sugar ferments directly, the formation of changed

cane sugar being consecutive to the formation of succinic acid,

I have tried various oxidising agents, but have found none better or more manageable than bichromate of potash.-Pharmaceutical Journal.

PHYSICAL SCIENCE.

An Account of the Water-Barometer Constructed and
Erected by ALFRED BIRD, Experimental Chemist,
Birmingham.

I HAVE the pleasure to send for insertion in the CHE-
MICAL NEWS an account of a water-barometer, which I
have had in perfect action for six years. It was shown
to the members of the British Association on their visit
to Birmingham, and a general desire having been ex-
pressed that an account of the instrument should be
published, I send you the following particulars and
drawings:-

In the construction of a water-barometer four things have to be attended to,

1st. The water must be deprived of air. and. The air must not again enter the water. 3rd. The water must go into the barometer, to the exclusion of the air; and

4th. The instrument must be so constructed that, while the atmospheric pressure within the instrument shall be uninterrupted, no air shall penetrate into the vacuum-chamber.

I will begin by describing the material. The tube is composed of metal and glass, and the three taps are those known as "Lambert taps." The size of the metal part is half an inch internal diameter, and is that sort of white-metal tube which is in universal use by gasfitters, called "compo." I believe it is an alloy of lead and zinc.

I recommend the compo tube made by Messrs. Stock, Brothers, and Co., in Birmingham, as it will stand an internal pressure of fifty pounds of air to the inch without leaking. The glass tube to show the "readings" is one inch internal diameter and six feet long. The brass Lambert taps are half an inch internal diameter. These taps are constructed internally with a cushion of indiarubber, pressed down by means of a brass plate acted upon by a screw, which makes them absolutely secure. I will next describe the upper and lower parts of the barometer in reference to the drawings. Plate 4. AA is the compo tube, having two enlarged sockets B, B, one and a-half inch in diameter and three inches deep. These sockets were made of brass, and their office is to receive the ends of the glass tube. To fix the glass tube C, about six inches of the compo tube was soldered to the bottom of the socket, and being inverted and fixed very steady, enough dry sand was poured into the compo tube to fill it up to the bottom of the socket B. The use of the sand is to prevent the cement from running into and stopping up the compo tube. The glass tube C, perfectly clean inside, was now placed in the socket; and being most carefully steadied to keep it upright, six inches of dry sand were poured down to keep the cement from rising up the glass tube C.

The cement was composed of two parts of gutta percha and one part of common black pitch. These two substances were heated in an iron ladle with a lip, till they became perfectly fluid and quite free from froth. A " low soldering-heat, a small quantity of the cement was copper bit" used by plumbers having been heated to poured into the socket. The copper bit was then applied to the outside, the effect being to perfectly liquefy the cement in situ. A little more of the hot cement was

Y

then poured in, and again the heated copper bit was applied till the socket was quite full of very fluid cement without any air cavities. As the cement cooled, it clung to the glass and metal, and became absolutely solid and air-tight. If the cement is poured in all at once, it is impossible to prevent crevices, which will let in air when the barometer is filled, causing the water gradually to descend till it falls out of the instrument.

A place being chosen on the staircase of my house, a flat board seven feet long and one foot wide, was fastened to the wall, upon which board was fixed the socketed glass tube C, and graduated scale F, from the top of which 422 inches were most carefully measured down to the "zero"-point E beside the cistern.

The scale F is to the right of the glass tube. It is made of well-seasoned boxwood, and is graduated to inches and tenths. The sliding-tube G, with the vernier H, is between the glass tube and the boxwood scale F. On the left side of the glass tube C is another slidingtube g, with a vernier h, to record position of top of tidal column of water at 9 a.m. the morning previously.

The glass tube, scale, and verniers having been securely placed on the board and perfectly upright, the gas-fitter proceeded to connect, by soldering, the remainder of the compo tube above the glass tube C, which was continued upwards till it entered nearly at the bottom into a round vessel K, made of zinc, four inches in diameter and eighteen inches high. Inside the vessel the tube coils round in a spiral, like the worm of a still. This vessel and spiral are not necessary to the action of the barometer; but as the spiral is in the part of the tube in which is the vacuum-chamber, it gives the opportunity of artificially cooling with ice or snow the included aqueous vapour, and thus determining by actual experiment the amount of correction required.

If the experiment of cooling the included vapour to 32° be tried in suramer, when the external temperature is 70° or 80°, the sudden cooling causes so great an evaporation from the surace of the water, and condensation in the upper part of the barometer, that a real rain-shower is produced, the condensed water running down the glass tube in innumerable pellucid drops in the most beautiful manner, thus perfectly imitating the condensation of invisible watery vapour in the higher regions of the atmosphere. When the compo tube leaves the zinc vessel, it is led up perpendicularly to the Lambert tap L. Above the tap L the tube still rises perpendicularly, when it suddenly bends down, leaving the end open at M.

I now describe the part of the barometer below the glass tube.

The compo tube being soldered on, was carried down to the cistern, not necessarily perpendicularly; for instance, the tube may descend at an angle of 30° or 40°, and may be led in any convenient direction. The entire instrument erected by me is inside the house, to escape a freezing temperature. At the lowest bend of the compo tube is a short upright tube, having at the end a Lambert tap N, to which is soldered a male screw of a 3th-inch gas union-joint O, the use of which will be understood further on. The compo tube now begins to ascend; and at the top of the bend is another Lambert tap P. Beyond this the compo tube bends down and reaches nearly to the bottom of the cistern, which is a one-gallon white glass narrow-mouth upright bottle R. The bottle

rests upon a stand S, which moves up and down by means of a set screw T, acting through a stout shelf UU; and the bottle is kept steady by means of the two

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uprights W, W, upon one of which is fixed the zeropoint E.

I shall now describe the method of filling the barometer. Four gallons of water were carefully distilled, and being put into a perfectly clean and new tin oil-can with a narrow mouth, the water was boiled for one hour over a bright fire, to drive out the air. While still boiling, two quarts of olive oil were poured in. This slightly increased the pressure in the water underneath, causing the last remains of the air to rise with the steam in jets or spirts through the stratum of oil. The instant ebullition was stopped, the oil closed over the boiled water, and it became hermetically sealed from the atmosphere. The contents of the tin can were now cooled, and the can X was placed above the top of the water barometer. A piece of 3th-inch gutta-percha tube Y Y, sufficiently long to reach from the can X above to below the very bottom of the barometer, was procured, and one end of the tube was put into the mouth of the can X, the end passing through the supernatant stratum of oil down to the bottom of the water underneath. At the other end of the gutta-percha pipe Y is a 3th-inch tap, terminating with a 3th-inch female screw union-joint Z. The gutta-percha pipe being in position, and hanging down as seen in the drawing, became a syphon; and the air being sucked out, the water at once came over, and was stopped from running away by turning the small tap Z. The female union-screw at Z being tightly screwed on to the male screw-joint O, the water was ready to enter the barometer.

The first thing to be done was to displace the air in the bend of the tube, reaching from the tap N at the bottom to the extreme end of the compo tube in the cistern R. This was done in the following manner :The cistern or bottle was taken away and filled quite full to the very brim with best olive oil; the three Lambert taps being all open, and the bottom end of the "compo" tube hanging down, the small gas-tap Z was opened; the water then began to ascend both legs of the barometer, and when it reached the tap P, it passed over and ran out of the end of the tube which was hanging down. At that instant the stream was stopped with the thumb, and, the tap Z being turned off, the bottle full of oil was brought to the thumb which stopped the end of the compo tube and kept in the water. The thumb supporting the tube was now put into the oil, and the end of the tube slipped down to the bottom of the oil. The bottle was then put into its place on the stand S, and the surplus oil being syphoned out, there remained in the cistern R about three inches in depth of olive oil, the compo pipe dipping into it nearly

to the bottom.

The next thing was to fill the longer part of the barometer, which was accomplished as follows:-The tap P being closed and the small tap Z opened, the water rapidly rose in the barometer; when the water had reached the opening M at the top, it was allowed to run a minute or two to carry any traces of air away which might have lingered in the tube. Tap L at the top, and tap N at the bottom being then securely closed, tap P was opened, and the column of water began to descend and to accumulate in the cistern R under the stratum of

olive oil. As the column fell it was narrowly watched in the glass tube, but not a bubble of gaseous matter was observed. On examining the cistern R, it was found that the oil did not quite reach the zero-point E, more oil therefore was poured in till the zero-point E and the level of the oil were coincident. The graduated scale was now looked at, and it showed that the column of

water was 400 inches high, the mercurial barometer being 30.4 inches, and the temperature 67°.

In order to see whether gaseous matter would accumulate in the vacuum chamber, the gutta percha syphon was allowed to remain in its place for some weeks, and four different times tap P was closed, tap N opened, with tap Z, thus filling the barometer up to tap L at top, which being opened allowed the water and gaseous matter, if there had been any, to flow out at M. On closing tap L and tap N and opening tap P, the column of water again fell; and after syphoning out the surplus water from under the oil in the cistern till the oil was level with the zero-point E, the column of water was found on the four different trials to be exactly the same height on the scale after each trial as before. It was, therefore, plain that no gaseous matter had accumulated above the water, and that, with the exception of the vapour of water, it was a perfect vacuum.

One or two precautions are required in order to ensure success. In the first place, the water must be distilledfor if the water contains "earthy salines" or colouring matter, it is certain, by the constant evaporation and precipitation in the working part of the glass tube, to crust it over so completely, that in a few months the water becomes invisible; pure distilled water is, therefore, indispensable. Then, if the slightest leak in the barometer exists, it will infallibly bring the instrument to grief. In order, therefore, to be sure that the barometer was sound (before the water deprived of air was put in), I closed tap L at top and tap P; then, connecting the gutta percha tube with the "street waterworks" pressure, I allowed it to enter the barometer till the included air was contracted to one-fourth of its length having a pressure of water under it of between 40 and 50 lbs. to the inch.

The barometer stood this internal pressure for ten hours without the air being forced out. I therefore concluded that if the barometer would stand this great pressure inside, it would stand 14 lbs. to the inch pressure on the outside, and without hesitation I filled it with the prepared water.

As the instrument is made by a gasfitter, it would be easy to put the whole of it together, Lambert taps included, and to prove it with some powerful water-pressure before the instrument is taken to the place where it is to be erected. Also the water deprived of air and covered with a stratum of olive oil in the tin can could be sent, if necessary, 100 miles away without the possibility of any air getting into it. If a gutta percha pipe is not to be had to fill the barometer, a piece of compo tube will answer every purpose, which, when done with, is none the worse for gasfitting purposes.

I shall conclude with some account of the action

of the water barometer. In the Philosophical Transactions for 1832 is a description by Mr. Daniell of a water barometer which he erected at the Royal Society's Rooms, at Somerset House, which was in action for two years, but afterwards got out of order. In describing the action, Mr. Daniell states that "the water appears to be in perpetual motion, resembling the slow action of respiration.'

I can fully corroborate Mr. Daniell in this particular, and from careful and continued observation am able to state that the times of the oscillations_are about every four minutes and twenty seconds. It is requisite to watch the oscillations with a magnifier, as they vary from the twentieth to the thirtieth part of an inch, which distance can be well observed when magnified. But the most surprising oscillations in the

NEWS

water barometer are during a thunderstorm accompanied with great falls of hail and heavy rain drops. I have given a chart of five minutes' readings for one hour and five minutes during a heavy thunderstorm from the north-east, which passed over Birmingham July 20, 1859. The upper curved line shows the water oscillations, and the lower curved line shows the oscillations in the mercurial barometer. The temperature is recorded at the foot. It will be observed that while the watercolumn rose and fell in a most surprising manner, the mercurial column showed hardly any motion, which was of a laggard character.

At 4.20 p.m. the storm reached its climax, the heavens grew darker overhead, and the water rapidly descended, causing a most impressive feeling on the mind, when suddenly came a terrific blaze of lightning, instantly followed by the "thunder cannonade" (if I may so call it); then down came the hail and heavy rain, and as the sky began to brighten the water commenced to rise, and in the next five minutes it had risen more than fourtenths of an inch.

Since Sir John Herschel proposed his new theorythat the disruptive electric discharge is the result, and not the cause, of the sudden condensation of cloud into "rain drops," in consequence of the cloud coming in contact with an extremely cold and dry current of air-it has occurred to me that the sudden increase in the density of the air, as shown by the rise of the watercolumn, may be due to the sudden precipitation of raindrops of unusual size, leaving the atmosphere drier and consequently denser; it being well established that the mercurial column is always high when the air is dry,

and vice versa.

I conclude this account of the water-barometer by stating that the object with which it is written is to give practical directions for the construction of these noble instruments with a view to their becoming common for the furtherance of meteorological science.

The total cost of the materials need not exceed 37.,
exclusive of gas-fitter's time.
Birmingham, November 14,

3.45 pm. 3.50 p.m. 3.55 p.m. 4.0 p.m. 4'5 p.m.4.10 p.m. 4.15 p.m. 4.20 p.m.4.25 p.m. 4.30 p.m. 4.35 pm. 4.40 p.m. 4.45 p.m.
Light-
Dark
Heavy ning and
o'erhead Heavy
thunder; thunder;
thunder rain;
rain. heavy
light- wind.
rain.
ning.

Water Barometer.

Dark; thunder

Heavy rain, but brightening.

Light-
ning,
Thunder thunder, thunder; Distant Light
rain thunder. rain.
hail, and
stopped.
rain

Mercu

Distant

Distant lightning. thunder.

Rain

rial steady; Baro

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no wind. meter.

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Temp. F. 75°

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74° Chart of one hour and five minutes' readings of the Tidal Oscillations in the Water Barometer, during Thunder storm, July 20th, 1859.

PROCEEDINGS OF SOCIETIES.

SOCIETY OF ARTS.

CANTOR LECTURES.

which have a special reference to digestion and respiration; and, secondly, those which have a more immediate connection with the human system in their direct action as therapeutic agents.

DIGESTION.-Man requires several varieties of food to

"On some of the most important Chemical Discoveries made maintain the health and strength of the body. One of

within the last Two Years."

By Dr. F. CRACE CALVERT, F.R.S., F.C.S.

LECTURE 3.

Tuesday, April 18, 1865. On the Discoveries in Physiological Chemistry.-I intend in this lecture only to give you a general outline of some of the main facts connected with the phenomena of digestion and respiration, introducing as I proceed some of the most important chemical facts connected with that branch of science discovered or observed within the last two years. To enable you to appreciate more fully the importance of those discoveries, I shall divide my lecture under two principal heads-first, the studying with you those facts

the most important of these is atmospheric air, which is chiefly used to maintain the heat of the body so essential to vitality, by oxidising the various substances taken as food, or by oxidising the tissues which have been destroyed in the body by the wear and tear of life, and which, having fulfilled their functions, require to be removed, that new tissues may replace those which have disappeared. The next class of food which man requires are fluids, which are chiefly represented by water, either pure or mixed with other substances, and which fulfil in the body two principal functions-that of carrying into the stomach and the intestines various nutritious elements which have been taken as food, and conveying them into the blood by endosmosis, or the force called by Mr. Thomas Graham, the Master of the Mint, "diffusion."

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