PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. ORGANIZED UNDER THE NAME OF THE MECHANICS' CLUB, MARCH 2, 1854, WHICH NAME WAS CHANGED TO THE POLYTECHNIC ASSOCIATION, MARCH 16, 1859. RULES ESTABLISHED FOR ITS GOVERNMENT BY THE BOARD OF SCIENCE AND ART. First. A Club for the promotion of manufactures, arts, and for the discussion of mechanical subjects, is created under the name of the Polytechnic Association. Second. The Polytechnic Association is an agent of the committee of arts and sciences, and is under its entire control, in the same manner as the Farmers' Club is of the committee of agriculture. The transactions of the Association are in the name of the American Institute. Third. The committee of arts and sciences appoint, annually, the chairman and secretary of the Polytechnic Association. In the absence of the chairman and secretary, persons to supply their places will be chosen at the meetings of the Club. Fourth. Every member of the American Institute shall become a member of the Polytechnic Association, by signifying his intention to the chairman thereof. Fifth. The name of any person eminent in practical mechanics, engineering, mathematics, astronomy, chemistry, natural philosophy, social philosophy, geology, mineralogy, practical mining, meteorology, natural history, manufactures or the arts, may be proposed by the members of the Association (by ballot, five-sixths of those present voting affirmatively) to be an honorary member of the Polytechnic Association of the American Institute; and when so proposed, if approved by the committee of manufactures, science and arts, of the American Institute, a certificate of membership shall be issued by said committee. Sixth. The Chairman of the Polytechnic Association is authorized to arrange sections, or standing committees, embracing all the physical and exact sciences, particularly those named in section second of these rules, and to appoint a committee for each section, who shall report the doings of the sections to the Association. Members, and honorary members, shall be entitled to seats in those sections. Seventh. Such papers read at the Polytechnic Association as are accepted for that purpose, will be printed under the direction and at the expense of the American Institute, which also provides a place of meeting, lights and fires. No other expenses are to be incurred, except by special appropriation of the American Institute, according to the rules and by-laws; nor any liability incurred by the Institute, except on special resolution. Eighth. The meetings of the Polytechnic Association are free of all expense to those who attend them. Ninth. The Polytechnic Association shall select, in advance, a subject [AM. INST.] 22 for discussion at each of its meetings, which subject shall be announced in the call of meetings. Tenth. Written communications to the Association are to be read by the secretary, unless objection is made; and if objected to, will be read, if it be ordered by a majority of the members present. Eleventh. The Polytechnic Association will recommend what papers read before them, or what part of other transactions they judge worthy of publication, to the committee of arts and sciences, by which the publication may be ordered in its discretion. Twelfth. No person attending the meetings of the Association shall speak more than once on any one subject, nor shall occupy, in such speech, more than fifteen minutes, except by permission of the Association. Thirteenth. The chairman may invite any person to address the meeting or to participate in the deliberations, but such person, not a member, shall be announced as a visitor. Fourteenth. Topics presented for consideration, or the announcement of a discovery or invention, improvement or novelty, or the exhibition of any machine or part thereof, or any manufacture or article, must be preceded by a statement setting forth the point, in writing, to be deliberated upon. Fifteenth. Any person desiring to put on record any supposed or real discovery in science, manufacture or arts, may address a communication to the chairman of the Association, under seal and properly indorsed, which shall be preserved in the archives of the American Institute as evidence for the party depositing the same. Sixteenth. In all cases not provided for by the rules, Jefferson's Manual shall be taken as a standard. Seventeenth. The official reports of the meetings of the Association shall lie upon the desk of the recording secretary until 11 o'clock of the day following the meetings, for the inspection of members, and such corrections as are necessary before going to the public press. Eighteenth. The minutes of the previous meeting shall be read at the opening in order for correction, unless otherwise directed by the meeting. Nineteenth. No argument is allowed between members. Facts alone are to be stated. Twentieth. All questions of order are decided, without appeal, by the presiding officer. AMERICAN INSTITUTE POLYTECHNIC ASSOCIATION, The Chairman, Prof. CHAS. A. Joy, presiding. THE MANUFACTURE OF SOAP. The Chairman opened the discussion with the following remarks: It is not known when the manufacture of soap was first introduced. We find mention of it in our earliest classical writers, and in the Old Testament; in Jeremiah, ii. 22, is found the expression, "Though thou wash thee with niter and take thee much soap ;" and in Malachi, iii. 2, "for he is like a refiner's fire and like fuller's soap:" but it is doubtful whether the soap here alluded to was made of the same materials as are at present employed. The niter mentioned in Scripture was not our saltpeter, but an impure sesqui-carbonate of soda, procured from certain lakes in Egypt. Solomon was acquainted with the action of an acid upon this salt, as he says in Prov. xxv. 20: "As he that taketh away a garment in cold weather and as vinegar upon niter, so is he that singeth songs to a heavy heart." Pliny calls it nitrum, and relates the circumstances attending the discovery of glass by its accidental fusion with silica, on the shore where the sailors were using it to support their kettles while cooking their dinner. The difference between soda and potassa was not known to the ancients, and this was first recognized by Duhamel in 1735. The alchemists were of the opinion that the alkali of plants was produced by the burning, and it was not until 1764 that it was shown to be present in the living plant. According to Pliny, the Romans learned the art of soap making from the Gauls. Pliny says: "Soap is an invention of the Gauls, and is used for giving a reddish tint to the hair. It is prepared from tallow and ashes, the ashes of beech and elm being preferred; there are two kinds of it, the hard and the liquid, both of them much used by the people of Germany, the men in particular more than the women." The city of Pompeii contained a complete soap-boiling establishment. It was near the sea shore, conveniently placed for the importation of the blocks of soda (niter) from Syria, and next door to the custom-house. The works were uncovered, after having been buried more than 1,700 years, and found in a tolerable state of preservation. The first room contained lime soap. In the second were five oval vessels made of cement and coated with hard stucco, which had been used in the manufacture of soap. It is a curious fact that the pumice stones which rained down upon Pompeii and drove out the soap boiler of that day, are now ground up and used by our manufacturers in the preparation of sand soaps. Whatever may have been the origin of this manufacture, it is clear that it was carried on in a thoroughly empirical manner for many centuries. We are indebted to a man still living for our knowledge of the scientific principles which lie at the foundation of this important industry. The French chemist, Chevreul, first announced to the Academy of Sciences in Paris, in a paper dated July 5, 1813, his discovery of the compound nature of the fatty bodies. Previous to that time, fat had been regarded as an unmixed organic substance; Chevreul showed it to be composed of several salts, which he called stearine, margarine and olein. These bodies will be described by the gentleman who is to follow me. The influence of Chevreul's discovery upon the manufacture of soap and candles was immense; and so great has the industry become that all parts of the world have been laid under contribution for the supply of the raw material. There is an oft quoted sentence in Liebig's Letters on Chemistry: "Die Seife ist ein Massetab fuer den Wohlstand und die Cultur der Staaten." (Soap is a measure of the prosperity and civilization of a people.) Liebig refers to the endless threads of manufacture which are bound up with this industry. The extensive supply of soda ash has suggested its use in the manufacture of glass and in the preparation of soap. Sulphuric acid was necessary in its manufacture, and the supply of this acid became so great that its application increased in proportion. To make sulphuric we need nitric, and for nitric we send to explore and civilize South America, and obtain nitrate of soda, and thus diminish the demand for saltpeter and render that available for gunpowder. Hydrochloric acid is an incidental product in the manufacture of soda ash, and this acid being remarkably cheap is extensively used in the preparation of bleaching powders, and in many manufactories; and thus one discovery ramifies in every direction and tends to the civilization of people in remote countries. In this respect, the manufacture of soap is a measure of the prosperity of a people. I shall leave the practical operations of soap making to gentlemen who are familiar with the subject. It is known that when a great number of bodies are buried in trenches under certain conditions, a peculiar change takes place. The olein and glycerine are often removed, and pure acids (stearic and palmitic with ammonia) remain behind. The body retains its natural shape. During the removal of the bodies of the victims of the cholera buried in potter's field on Forty-ninth street, numerous examples of this decomposition were observed, and a body is now preserved in the museum of the College of Physcians and Surgeons on Twenty-third street. This fat is called adipocere, from adeps, fat, and cera, wax. It has been thoroughly investigated by Dr. Wetherill, of Philadelphia. The specimens on the table are from the potter's field, and the soap and candles were prepared from the adipocere in the course of some scientific experiments. The Chairman concluded by giving a detailed account of soda ash, illustrated by diagrams and by specimens taken from each step in the process. He then called upon a German chemist, Mr. Engelhard, of St. Xavier College, to take up another branch of the subject. Mr. Engelhard.-Mr. President: The fats and fixed oils, used in the manufacture of soap, of different qualities and properties, are taken both from the animal and vegetable kingdoms. Chemically pure fats have neither taste, smell nor color, and leave a grease spot on paper. They are lighter than water, having generally a specific gravity of .91 to .94. All of them are soluble in ether; a few in alcohol, and none in water. Heated by themselves they will resist a temperature of 500° Fah., but above that decompose; hence their name, fixed oils, in contradistinction to volatile oils, which may be distilled without alteration. When oils in vats are heated with the hydrated alkalies, such as lime, potash, soda, a process called saponification takes place. To count up all the different constituents of the known fats and fixed oils would require too much time, and therefore I shall speak of those only which constitute lard, suet, palm oil and olive oil. All fats are mixtures of two, three or four closely allied substances, namely, stearine, palmatine, margarine-solid at ordinary temperatures-and one liquid, olein. The more olein a fat contains in proportion to the other constituents, the less solid is it. [The speaker then described in detail the four substances named. They are all composed of carbon, hydrogen and oxygen, in the following proportions: .C114 H104 019] 12 If a fat or fixed oil is heated with a caustic hydrated alkali, the following decomposition takes place: Stearine+6H0-glycerine+3 stearic acid and 3 water. Stearine C114 H110 012-3 Stearic acid 6 Water 36 C H35 03 06 6 C114 H116 O:8 Stearine, palmatine, margarine and olein consist, therefore, of stearic, palmitic, margaric and oleic acids, with the base glycerine. In soapmaking, the following decomposition takes place: 35 8 C114 H110 0126 (HO)+3(KO)=3 (KO)+3(C‰6 Hз5 О3)+С ̧ H, 0+3(HO) The stearate of glycerine is decomposed and stearate of potash is formed. We substitute for the base, glycerine, in the original combination, a new, stronger base, potash, and form the new salt known as soap. [The speaker next described the several acids mentioned, and pointed out the proper methods of detecting the various adulterations used in the manufacture of soap.] The President.-There is a gentleman present who will give us some information in relation to vegetable soaps. Mr. Austin. In some countries the natives use the seeds of some plants as substitutes for soap, of some plants the bark is used, and of others the root. Such plants are found to abound in an acrid, narcotic principle—a vegetable alkali, called saponin; but whether their virtues as purifiers of linen depend upon chemical or mechanical action is a question I believe not yet settled. These plants are confined to a very few widely diverse natural orders of the vegetable kingdom, and frequently to a very few genera of those orders. However, it is, no doubt, contained in many plants where it is not at present suspected to exist. I will mention briefly a few of the more important plants containing saponaceous secretions. The seeds of many plants of the soap-berry family, as the horse-chestnut, contain this matter to a great extent. The fruits of these latter lather freely in water, and " a few of them will cleanse more linen than sixty times their weight of soap." Pounded and thrown into water they stupefy fish. There are two or three genera belonging to the natural order-Rosacea and the tribe Guillaiæ-remarkable for their saponaceous secretions. Guillaia saponaria yields one of the barks called Guillaia, used as a substitute for soap. "Two ounces of this bark are sufficient to wash a dress," and it is said to give a remarkable luster to wool. It contains a substance which occasions voilent sneezing, and which is allied to saponin. The California soap plant belongs to the natural order-Lilliacea, and to the Scillæ or onion tribe. It is used by the natives as a substitute for soap. This plant produces a thick bulb, which is inclosed in a remarkably large and thick bundle of black, coarse fibers-the remains of the nerves of former leaves. All plants secreting saponaceous matter (and I have mentioned only some of the more important ones) contain also an acrid, narcotic, and often highly poisonous principle, and, no doubt, the two principles are identical |