THE chem Lab RMICAL LABORATORY OF HARVARD OUL. CHEMICAL NEWS Edited by AND JOURNAL OF PHYSICAL SCIENCE Sir Wm. Crookes, O.M., F.R.S.] (WITH WHICH IS INCORPORATED THE "CHEMICAL GAZETTE"). Establish Published Weekly. Annual Subscription free by post £1. Entered at the New York Post Office as Second Class Mail Matter Bstimating the Quality of Paper A Gaseous Spring containing a High Percentage of Helium, by The Scientific Week ..... 23 To be obtained from HUGO LORENZ, 7-8, Idol Lane, Great Tower St., London, E.C., Licensed Trader in Alcohol and Spirits of Wine. Stock kept in suitable packages ready for immediate use. PLATINUM Utensils.-We supply all forms and sizes of Platinum Utensils and Apparatus for Chemical and Physical purposes. All our utensils are hammered to shape, tested, and finished in the best manner. All kinds of Platinum scrap bought for cash or taken in exchange for new.-DERBY and CO., Ltd.. 44. Clerkenwell Road, London, E.C. OZONE APPARATUS for the LABORATORY. 12 Page Illustrated Pamphlet, fully describing various forms of Apparatus and method of using them, Post Free to Readers of the "Chemical News.' OZONAIR, Ltd., 96, VICTORIA STREET, WESTMINSTER, LONDON, S.W. Registered as PRICE 44. Wanted by a Chemistry Student, temporary Occupation during vacation.-Address, A. G., 59, Wroughton Wan anted for Chemical Works, Chemist with Research and Works experience. Give full particulars.-Address, "Research," CHEMICAL NEWS Office, 16, Newcastle Stree Farringdon Street, London, E.C. The Owners of BRITISH PATENT No. 18342 of 1909, entitled "Improved Process of Manufacture of Viscous Spinning Solutions of Cellulose," are desirous of disposing of the Patent or entering into working arrangements, under licence or otherwise, with firms likely to be interested in the same. A copy of the Patent Specification and full particulars can be obtained from and offers made (for transmission to the owners) to MARKS and CLERK, 57 and 58, Lincoln's Inn Fields, London, W.C. KAHLBAUM'S PURE CHEMICALS NEW PRICE LISTS NOW READY. Free on application. SOLE DEPÔT JOHN J. GRIFFIN & SONS, LTD., KINGSWAY, LONDON, W.C. July 11, 1913 L. OERTLING, The Proprietor of the BRITISH PATENT MANUFACTURER OF BALANCES. Maker to H.M. Govt. (Standards Dept., the Government Laboratory, Royal Mint, India and Colonial Offices); the National Physical Laboratory; the Bank of England; Standards Bureau, Washington; &c. Chemical Balance. No. 6 SB, No. 17 63/10, relating to "Process for the Destruction of Hairs, Horsehairs, Finger Nails, and Horny, Gelatinous, and the like Substances contained in Floss and Waste Silk in general," is desirous of entering into arrangements, by way of Licence or otherwise, on reasonable terms, for the purpose of exploiting the same and ensuring is full development in this country. All communications should be addressed to Mr. SEIGNOL, 32, Rue Servient, Lyons, France. THE AMATEUR PHOTOGRAPHER Cloth Gilt-lettered Covers for Binding the Half-yearly and PHOTOGRAPHIC NEWS. Edited by F. J. MORTIMER, F.R.P.S. Price TWOPENCE-Every TUESDAY. The Leading Paper for Everyone interested in Photography. Special Articles on PICTORIAL and MODERN SCIENTIFIC PHOTOGRAPHY. The best and brightest Photographic Weekly for the Beginner or Advanced Worker. PROFUSELY ILLUSTRATED. Specimen Copy free. Office: 51, LONG ACRE, LONDON, W.C. MARTINDALE'S Volumes of the CHEMICAL NEWS may now be obtained. Price 1/6 each (post free 1/8). Volumes Bound in Cloth Cases, Lettered and Numbered at as. 6d. per volume CHEMICAL NEWS OFFICE. 1C, NEWCASTLE ST., FARRINGDON ST., E.C. SULPHUROUS ACID and SULPHITES. Liquid SO2 in Syphons, for Lectures, &c. PHOSPHORIC ACID and PHOSPHATES. Apparatus and Reagents CARAMELS & COLORINGS For Chemical and Bacteriological Research. SPECIALITIES: MARTINDALE'S BURETTE STAND 9/-, 15/42/ Analytical Price List post free. Teleptons-1797 Paddington. W. MARTINDALE, 10, New Cavendish St., W. for all purposes. A. BOAKE, ROBERTS & CO. (LIMITED) Stratford, London, E. It is a well recognised fact that an accurate knowledge as to the materials and chemicals entering into the composi ACTION OF SEA WATER ON FLANGES USED tion of a paper is of great value to every paper maker who 4. Pounds. 27'70 27'79 27'45 27'51 may be called upon to match a given sample. Manufacturers at present must depend on their personal judg. ment for such information, and the ability to correctly judge papers may only be acquired by long years of experience. To such an experienced man the first look at a particular sheet of paper reveals the general class to which it belongs, whether writing, printing, wrapping, board, &c. A second glance reveals the relative grade into which the particular class is subdivided. This preliminary information at once brings to the mind of the experienced man a picture of the general process of manufacture required to produce such a paper. By the use of his sense of smell he, in many cases, is able to determine whether it is animal sized or not; he presses his tongue against the sheet and says whether it is "water-leaf" or "sized" paper, and whether "slack," "medium," or "hard" sized; if a coated paper his tongue will indicate it. Upon closer inspection and a liberal use of the sense of "sight" and "touch," he is able to estimate the weight per ream, the thickness of the sheet, the fibre composition, and general method of treatment in the beater room, on the machine, and in the finishing room. He may also be able to give an estimate of bursting strength and general folding quality. The result of this method of testing is only comparative, and therefore lacks fundamental necessity of numerical expression for record purposes. At the present time there is developing, both within and without the paper trade, a growing interest in the subject of paper testing. There is a demand on the part of the buyer for better methods to enable him to determine the quality of a paper. That there is this growing interest in the subject and a general demand for standard The mechanical tests of test-pieces, cast with the methods of testing is most conclusively shown by the work flanges, were as follow: Precipitation of Aluminium Hydroxide by Bromine from Aluminate Solutions.-W. Jakób. Bromine precipitates pure aluminium hydroxide from a boiling alkaline aluminate solution, and the reaction is quantitative and can be used to separate aluminium from chromium. The solution containing the two metals must first be treated with sodium hydroxide solution, drop by drop, till the precipitate dissolves. Then bromine water is added to the cold solution till the green colour is replaced by yellow. The solution is boiled and the aluminium hydroxide sepa. rates in a compact form. To remove the last traces of chromium from the precipitate the liquid is decanted off, and the precipitate is treated with water containing am monia and ammonium nitrate, boiled for a few minutes, and filtered off. The small quantities of precipitate clinging to the walls of the flask are separated by means of dilute nitric acid, and added to the main bulk after neutralisation with ammonia. The method is not suitable for the precipitation of aluminium hydroxide in presence of sulphuric or boric acids.-Anzeiger der Akademie der Wissenschaften in Krakau, 1913, I. A. which is being accomplished in the commercial paper testing laboratories that are starting up in various parts of the country. This increasing general interest in paper testing has been the cause of developing a series of tests that apply both to the physical and chemical properties of a paper. These tests are not meant to give absolute values, but if due care is exercised in the selection of a representative sample and in making the necessary tests, then numerical values will be obtained which to a large degree indicate something of the quality of a paper. Such a method offers the only means whereby a record of a paper may be kept. In this discussion of paper testing, it should be distinctly understood that these tests do not cover every quality of property a paper may have. The degree with which one sample is a colour match for a second sample must depend upon the ability of the eye of the individual. The matter of "finish" is a second property, which so far cannot be expressed numerically, and for which there are no physical tests. The degree with which one sample conforms to another in finish is purely a personal element, and depends upon the experience of the individual. At the present time there are no physical methods by which an accurate comparison may be made to determine when a paper contains a larger amount of dirt than is acceptable, or just what degree of "wild formation" shall render a paper non-acceptable. These two properties of "dirt" and "formation" are left to the judgment of the individual, and depend on a hazy mental idea of what he individually believes to be a point beyond which a paper Paper read at a meeting held under the auspices of the Bureau of Standards at Washington, D.C, Jan. 13, 1913. From the Chemical Engineer, xvii., No. 3. becomes undesirable for the particular purposes for which it was intended. The laboratory testing of a sheet of paper then narrows itself down to determining those properties which have a nearly fixed value or may be expressed in definite numerical terms. These values are such that when due care is exercised two or more individuals using the same methods and samples and working independently will obtain duplicate results. In other words, such methods very largely eliminate the personal element of the indi vidual wherever the properties of a paper may be given a numerical value. The general examination of paper may be subdivided into three parts as follows: Microscopical examination. A microscopical examination will disclose the kind or kinds of fibres from which a given paper was made, and the experienced man will with considerable accuracy be enabled to estimate the proportions of various kinds of fibres used. The microscope also helps to indicate how much a stock has been beaten. The testing to determine the physical properties of a paper is divided into determining: weight per ream, thickness, bursting strength, tensile strength, folding endurance, expansion, and absorption. The chemical analysis will disclose the amount of ash retained and the amount and kind of size used. A chemical examination will also give much information in regard to colours used. All of this information is of the utmost importance in determining the quality of a paper. The principal purpose of a microscopical examination is to determine what fibre or fibres were used in making a paper, and then to estimate the relative proportion of each on a basis of 100 per cent for the total fibre composition. Such an examination requires the following apparatus beakers, test-tubes, slides for microscope, two long pointed steel dissecting needles, Bunsen burner, and tripod stand (or other means of heating sample), one large bottle of a per cent solution of caustic soda, one small bottle of 25❘ per cent hydrochloric acid, six small dark coloured glass bottles, with dropping stoppers for stains, small pieces of filter paper, and a microscope which for ordinary work should be capable of magnifying about forty-five times. The binocular microscope will be found to be best suited for estimating work where it is desired to study the markings and special characteristics of a fibre, then a microscope capable of magnifying from 150 to 200 times should be used. As all vegetable fibres are highly transparent and almost entirely colourless, when seen under the microscope, it is very necessary to use some staining solution to colour the fibre in order to bring out their size and shape and general markings. The best stain for this purpose is the so-called "Herzberg" stain, which is what is known as a selective stain, that is, it has the property of giving a yellow colour to most uncooked fibre, such as mechanical wood; chemical woodpulps are coloured in indigo blue; and cotton, linen, and some other fibres are coloured in wine red. The staining solution is made up as follows: The two solutions A and B are then mixed together and allowed to stand for twenty-four hours to settle, after which the clear liquid may be poured off and divided between two of the dark glass bottles with the dropping stoppers. All iodine solutions will fade in light, and should, therefore, be kept in the dark as much as possible. It is a very good plan to use two more of the dropper stoppered bottles to keep a concentrated solution of zinc chloride and water in one and a concentrated solution of potassium iodide and iodine in water in the second; these two solutions will be found handy in adjusting the Herzberg stain. The preparation of a sample of paper for the microscope is as follows:-Several small pieces of paper of about the area of a cent are cut from different parts of the sheet of paper; these pieces are then placed in a beaker and covered with per cent caustic soda solution, the whole mass is then brought to boil over a suitable heating device. After boiling for about a minute, the liquid is poured off and some tap water added to wash out the caustic soda, and two or three drops of a 25 per cent hydrochloric acid solution added to neutralise the alkali. The slightly acid solution is then poured off and enough of the small pieces of paper is pinched off and rolled into a ball of about the size of a pea. This small ball of pulp should be well rolled between the thumb and finger and then placed in a test-tube and the test tube about half filled with water. Care must be exercised to rinse the hands after working each sample, to keep from contaminating the sample following. The test-tube is then shaken vigorously until the paper has been entirely broken up and the fibres are well separated. A few fibres are next removed on the point of the microscope needle from the test-tube, and a small sample is placed on each end of one of the microscope slides. The slide should be held in the holder over some black surface, as it is a great help to the eye to look at the white fibres against a black background. The wet fibres on a slide may best be dried by covering them with good filter paper and left for a few minutes to dry in the air. The fibres are thoroughly dried and a drop of the Herzberg stain is added, and then the fibres are well "teased" out by the use of two microscope needles, a cover-glass is placed upon the fibres and well pressed down, all the stain pressed out around the edges of the glass being removed with filter paper, and the slide polished with paper or cloth. The slide is next placed under the microscope, and after studying the various fields an estimate of the proportion of each of the various kinds of fibres may be given. It is best to use four stains for this work, that is, each stain is of slightly different strength, as each one gives the best results on certain fibres. For example, a stain that clearly brings out the wine-red colour on cotton and linen fabrics, as a rule, usually does not give the best blue colour on bleached soda and sulphite pulp; the same stain on ground woodpulp has almost no effect at all. In making up a stain to produce the best colour on the particular fibre, the following points should be remembered: Two or three drops of water added to a good stain for rag and bleached chemical wood will tend to fade out the wine-red colour, the blue colour will remain nearly unchanged, and the yellow colour on ground wood will be brought out very much clearer. In other words, a good rag stain, when used on ground wood, produces almost no colouring of the ground wood fibres. The addition of two or three drops from the bottle containing the concentrated solution of iodine and potassium iodide, in water, will produce a deeper wine-red on rag fibres, while the addition of a few drops of concentrated solution of zinc chloride in water will produce a deeper blue on chemical wood fibres. It should be remembered that these iodine solutions CHEMICAL NEWS, July 11, 1913 Estimating the Quality of Paper. 15 will continually fade out, and that the best results may | which a strip of paper of definite size is clamped. The only be obtained when the stains give the proper colours. The easiest and best way in which to secure a stain of the right colouring capacity is to keep on hand the following pulps: Bleached soda and sulphite pulps, unbleached sulphite, ground wood, and beaten rag stock. The rag stock may most easily be secured by using a sheet of good quality of filter paper, which is always made from "all rag" stock. Now take small bits of the bleached soda and bleached sulphite pulp and thoroughly mix them, after first separating them in water in a test-tube. Place a small sample on a microscope slide, thoroughly dry the fibres, add one drop of stain, separate fibres with the needles, place cover glass in position, and place slide under microscope. Each fibre seen should be of a blue colour, the sulphite fibres appearing much wider and longer than soda fibres, and should show a lighter blue colour, as the fibre is more translucent than a soda fibre, while the soda fibre should take a darker blue colour. Soda and sulphite fibres should show a slight colour difference, and soda fibres being coloured a darker indigo blue, while sulphite fibres should be coloured a lighter indigo blue. If this colour difference is not clearly brought out, then either water or zinc chloride solution should be added, depending on whether it is desired to weaken or deepen the colours. Some rag fibres should now be added to the test-tube, and a second slide made up, using a bottle of stain which is intended to produce best results on mixture of rag and wood pulps. This second stain is adjusted by adding water, zinc chloride, or iodine-potassium-iodide, or all as may be needed, until the three fibres, soda, sulphite, and rag, are all clearly brought out. A third stain should be prepared for such papers as may contain ground wood by using mixture of ground wood and unbleached sulphite, and then adjusting the stains to give the best colours. The proper yellow for ground wood is the lemon yellow, never an orange yellow, as then the sulphite pulp is too slightly coloured and ground wood estimates are necessarily too high. The experienced man may by using this method get some very surprising results. The Bureau of Standards believes that in papers containing mixtures of rag and bleached chemical wood, a careful microscopical estimate is well within 5 per cent of the correct fibre contents. For papers containing ground wood, especially where the percentage of ground wood is high, then the degree of accuracy is within 10 per cent of the correct fibre contents. For laboratory use, the quickest sheet weighing device is the quadrant paper scales, so graduated that the corresponding ream weight-either 500 or 480 sheets-is read off directly in pounds. Thickness of a paper may best be determined by the use of a spring micrometer having a hand that travels around a circular dial. This dial is graduated into thousandths of an inch and may be read to ten thousandths. In using such a gauge care should be taken to see that the pressure on the paper is constant, and also that the pressure surfaces are large enough not to compress the paper. The bursting strength of a paper is determined with a machine by which the paper is firmly clamped against a rubber diaphragm, through which the pressure is applied to a circular area of the paper measuring one square inch. The actual pressure of the liquid under the rubber diaphragm required to burst the paper is registered on a carefully calibrated pressure gauge, reading pounds per square inch. An average of ten readings is taken as the correct bursting strength. The tensile strength of a paper is determined upon a suitable machine, capable of accurately recording the tension required to break a strip of paper, when held at each end by suitable clamps, and the clamps are moved apart until breaking of the paper occurs. The folding endurance is measured on a machine in clamps are held apart under definite tension and the paper is caused to bend back and forth upon itself until the fibres wear through at line of folding. The number of double folds is recorded automatically by a suitable device. Expansion of a paper may be determined by submitting the paper to different atmospheric conditions and noting resultant size of sheet at each change in the atmosphere. The measure of absorption of a paper is the height to which, in a given time, a liquid will rise by capillary action, when one end of a vertically held strip of paper is immersed in water. This test, as well as all physical tests, must be made under a uniform condition of humidity. The work of the paper laboratory at the Bureau of Standards comprises the testing of papers for the government service and the general public; also a study of methods of paper manufacture for the purpose of obtaining information of value in the preparation of govern. ment paper specifications. Information thus obtained is also at the disposal of the general public who may be interested in selling or buying paper under definite requirements. It is not the intention of this bureau to go into general commercial paper testing, for the reason that there are regular commercial laboratories that are well equipped to do this work. Tests in dispute between outside parties will be taken up as an absolutely disinterested referee; in such case the bureau will very willingly give all possible assistance. The equipment of the paper laboratory is at the service of the paper manufacturer as well as the user of paper for the investigation of problems of wide general interest, and it is desired to impress upon the trade and the general public that they are always welcome to such information as we may possess, provided such information does not come to us in a confidential manner. The United States Government throughout its various branches consumes 40,000,000 lbs. of paper each year. This large amount of paper includes almost every grade or kind on the American market. The acceptance or rejection of such a large and varied amount of paper necessarily involves good judgment on the part of the paper inspector, together with an intimate knowledge of the manufacture of all kinds of paper, and a knowledge of the various uses to which each grade may be put. Is it reasonable to expect to find one or even two men who combine such a knowledge ? It is the firm belief of the Bureau of Standards that all manufacturers and users of paper will readily recognise that a correct set of definite chemical and physical tests, when carried out under uniform conditions, will give more reliable results than could be obtained in any other way. It is also the belief of the Bureau of Standards that a knowledge as to the nature of our methods of paper testing, as well as the manner in which a paper specification is developed, will tend to convince the trade of the fairness with which this work is carried on. Royal Institution. A General Meeting of the Members of the Royal Institution was held on July 7th, Sir James Crichton-Browne, Treasurer and Vice-President, in the Chair. Prof. E. Rutherford was elected a Member. The Chairman announced the decease of Her Grace the Duchess of Northumberland, and the following resolution was passed unanimously:-Resolved, That the Managers and Members of the Royal Institution of Great Britain at the General Meeting this day, desire to record their sincere sympathy and condolence with his Grace the Duke of Northumberland, President of the Royal Institution, and with the House of Percy, on the decease of Her Grace the Duchess of Northumberland. |