730
JOURNAL OF CHEMICAL EDUCATION
APRIL, 1929
A CHEMICAL MUSEUM EXHIBIT C. H. SPIERS, LEATHERSELLERS' COMPANY'S TECHNICAL COLLEGE, LONDON, ENGLAND The easiest way to fill a museum is to assemble a collection of specimens in bottles, jars, dishes, etc., and to label them neatly. Such a collection is however "dead." It only comes to life when the visitor is conducted around the museum by a guide who knows the meaning of the specimens. This defect may be partially remedied by appending a written description to each exhibit, hut there still remains the defect that the objects are isolated. The visitor will obtain a series of separate impressions which he must connect together for himself. The task of collecting together a set of impressions for a synthesis is irksome. One may start touring a museum with the firm intention of systematically examining every object but very soon one is darting about haphazardly looking a t that which happens to catch the eye. Then the synthesis itself is difficult and without this synthesis much of the benefit of the museum visit is lost. The things seen on a given occasion must either fit together or fit into what has been previously seen or learned. While, therefore, it is desirable for each specimen to speak for itself, it is perhaps even more desirable that specimens should be grouped together in sets to bring out special ideas and this as vividly as possible. Under these conditions the museum is "live." The exhibits are self-explanatory; the aid of a guide is not necessary. Further, this "unit construction" enables the visitor with little time to gain the maximum benefit. Naturally, this kind of arrangement requires much more &ought and time than the more conventional one, if its object is to be achieved, and every display trick must be utilized. Recently, an anonymous donor gave the Leathersellers' Company's Technical College a grant for the purchase of new museum fittings and the author was called upon to utilize some of the space for displays illustrating the chemistry and physics of leather manufacture, the scientific control of the tannery, the chemicals used in the tannery, etc. In designing a display, the author worked on the basis that a successful museum exhibit will have many of the features of a well-dressed shop window. The individual objects must be neat; the arrangement must be harmonious; the exhibit as a whole must attract attention; the eye must be irresistibly brought to the principal feature and then led away to the subsidiary ones; the important points must he clearly brought out. One of the subjects chosen for display was the influence of water impurities on tannery processes. Water is one of the principal tannery chemicals. It is used in boilers for the generation of steam for heating and power. It is used for cleansing skins a t various stages during the conversion to leather and it is employed as the reaction medium for various
VOL6, No. 4
A CHEMICAL M u s e u ~EXHIBIT
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D l A GR A M SHOWING PROWRTIONOF DISSOLVED IMPURITY IN LONDON W A T E R
I
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GENERAL REMARKS
OF
WATER TUBE
0N TROUBLES CAUSED BY
IMPURE WATER
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SPECIMENSOFLEATHER SPECIMENS DYEDwlTn BASICDYES ILLUSTRATING EFFECTS D I S S O L V E D IN
73 1
OF
SOFTANDHARDWATERSTH.ANDPHOYBOILERWORKING
\ SPECIMENSOF LEATHERSHOWINS STAINS DUET0
LIME BLAST
chemical changes occurring in the tannery. In this last capacity, it is used as a solvent for soaps, dyes, adds, tannins, etc. The effects of water impurities on boiler working are well known. The impurities react with many of the tannery chemicals causing (1) wastage of chemical, and (2) production of inferior leather owing to stains, interference with finishing operations, etc. The important features in connection with tannery water have been brought out in the manner depicted in the diagram. The case available has glass walls and measures 66" X 36" X 20'. It has three staggered glass shelves. At the top are exhibits showing the amounts of impurities per gallon of London water. On the two lower shelves are exhibits showing the reactions of these impurities with tannery chemicals. On the floor of the case are technical speamens demonstrating the decks of the impurities in working practice. The rectangles represent cards bearing concise descriptions of the various items. The lines connecting the cards represent ribbons of different colors. The eye naturally starts at the central card and travels along the ribbons to the various speamens. The effects of temporary hardness, permanent hardness or iron are easily picked out by blue, red, or green ribbons. The case vividly teaches the brief facts relating to a definite problem. All the tricks of the window dresser are used and indeed his various little gadgets--clips, struts, stands, etc.-have been found most useful in setting up the exhibit. Were a larger case available, one might add objects illustrating water testing and softeninfi
