THE simplicity and directness of aim observed in the choice of materials in the old arts and crafts have always elicited the admiration of thoughtful men and the wonder of curious ones. Consider, for example, how animal glue so happily. answers the needs of the joiner for uniting two pieces of wood; how easily it can be treated and how perfectly it shows both tenacity and adhesion. This valuable and complex substance was known to the Egyptians, and they are said to have left on record descriptions of how to prepare it of best quality. As to the metals, we can understand that the ancient artificers, once they became acquainted with the different ones, perhaps by accidental smelting, should avail themselves of such obviously valuable aids; thus a1.so of wood and of stone for building materials; but there are many other substances whereof the choice i& remarkably discerning and apt, strongly suggesting that it was preceded by much patient investigation and keen observation. Was it some clay worker making bricks for building who discovered that soft clay might be written upon and then burned as tiles to make imperishable historical records? Who first observed the silk worm and learned how to unwind the cocoon, strengthen the thread and weave cloth from it to make the garments of the rich? The ancients knew how to mat wool fibers together and make felt. They must have understood that the character of the surface of this fiber is unlike that of others and why it makes felting. Those ancient craftsmen evidently possessed a spirit which was eager for research and experiment and which overcome many difficulties of isolation and poverty. Modern times can point to triumphs of its technologists in the similar search for suitable materials to apply in the arts. But the needs now are broader by the very fact of our greater resources to draw from and our vastly larger fields of activities. It becomes necessary for us to develop a much greater devotion to research into the properties and adaptations of materials. We cannot be contented with our present knowledge. We must have a larger variety of materials than we are yet acquainted with if we are to advance in the arts of construction, transportation, agriculture and manufactures. We need also a better acquaintance with those we have if we are to use them •to best advantage and equal the older craftsmen in aptness of choice. The uncovering of a new product or the application of newly discovered properties of an old one haB possibilities for adding to the wealth of nations which can hardly be estimated. The extraction of oil from cotton seed, an industry which did not exist before the civil war, has now reached a production valued at one hundred million aollars annually. The virtue that lies in carefully selecting and compounding cement materials before calcining them at a high heat rather than taking them at randJm and burning at low temperatures has, in twenty years lapse c time, given us the Portland cement industry totaling seventy million dollars annually, and has almost extinguished the natural cement industry which pro(uced not more than a twentieth of this in its best year. The industry of manufacturing dynamite has grown. WI more than fifteen million dollars worth are manufactured annually. What will be the corresponding value when this powerful agency has been made safer by the lowering of the freezing point of nitroglycerin and by other stabilizing improvements and shalI be introduced into agriculture for the breaking up of subsoil, clearing of forests, and draining of swamps? Lastly, we must exercise a control over all materials we purchase, examining them criticalIy both to detrrmine suitability and to appraise the market value. Testing Before Buying The Economics and Aesthetics of Materials E.'” Dr. Charles F. MeKenna Engineering, which now involves so much more than was meant by the term a generation ago, is more concerned than ever over the qualities of materials which are offered to it. In attempting to determine these it fnds itself in need of resorting to instrumental means of manifesting differences in properties in order that fallible human judgment may be eliminated as much as possible. The movement begau by demands for th .. preparation and preservation for duplication of the standards of weight and measure. Railway engineering was insistently calling for a deeper study of iron and steel. This resulted in a most intimate investigation of the chemical constitution of steel and brought about at the same time the development of machines and apparatus for observing almost all the physical qualities of materials. Later years have brought us demands of the same nature, not only from the constructional arts, but also from every branch of manu- A corner of a private paper· testing laboratory. facturing. The practice of the art of testf:g now includes the chemical, physical and mechani.al studies of all kinds of iron, steel, copper, alloys, stone, cement, clay, coals, paper, paint, rubber, wood, textiles and a host of materials used in technology. Out of this has grown a larger development of the governmental agencies which were established only as repositories of the standards of measures such as was originally the case with the Conservatoire des Arts et Metiers in Paris. Many nations endowed scientific stations for the applications Qf precision measurements. The Imperial Physical Teehnical Institute of Char-lottenberg, near Berlin, is one of these, and is the' most important and valuable standardizing laboratory in the world. It is composed of two departments, one dealing with the standards of measurement and obtaining correct data as to physical forces; the other dealing with determinations of the accuracy of technical instruments submitted for the purpose and to be absorbed in their turn into use as standards in other laboratories. A staff of more than one hundred experts and assistants is entirely supported by the government for this purpose. United with this is the Royal Material Testing Bureau of Gross Lichterfelde, whose object is to apply results of research directly to teehnical problems and routine testing of materials. It has the following departments: 1, metal testing; 2, building material testing; 3, paper and textile testing; 4, metallography; 5, general chemistry; 6, oil testing. It employs over two hundred persons and makes many thousand tests annually in these departments. Thus the co-relation of research and technical interpretation can be adjusted nicely under the guidance of the most skilled and patient investigators that the realm affords. France. Austria and England have institutions of like aim. We are now abreast of the world in this important application of science, for our Bureau of Standards in Washington, founded by Act of Congress of 1901, has been operating for several years under the able direc tion of Dr. S. W. Stratton, and has made many valulble contributions to the literature of the science of exact measurement. Congress has continued to provide generously for the maintenance and extension of this work. Regarding the value of the chemical departments of the bureau, Dr. Stratton has said: “The relation of the chemical work to that of the other sections of the bureau is exceedingly important. Scarcely a problem can be taken up concerning construction or the properties of materials that does not involve chemical analyses or the co-operation and advice of expert chemists. The entire work of the bureau has been greatly strengthened and its efficiency increased by the organization of the work in chemistry." A new section has been organized to provide for the routine testing required by the departments in making their purchases of supplies. Perhaps the most prominent organization under onE head availing itself of chemical examination and testing of all its supplies is the Isthmian Canal Commission, since its work constitutes the largest piece of construction and the largest housekeeping proposition that have ever been combined. As this calls for an expenditure of $300,000,000 within a decade, it can be seen that the supplies of materials are an important factor and demand close scrutiny. These methods are applied by the Commission and the Purchasing Agents' office is concerned over the quality of the bronze wire bought for mosquito screens just as it is over the Portland cement which will be required for the dams and locks. It wants to knol the composition and strength of the steel used in construction, the Babbitt metal used in engine bearings, the dynamite used in blasting, and so on through a thousand things as diverse. This is on the very correct theory that the United States should get full value for everything it purchases, small or large. September l, SCIENTIFIC AMERICAN Besides these government laboratories there are many others in this country which practice chemical and physical testing of materials for determining their qualities and values. Some of the largest of them are operated by the railroad companies. and quite a number by the great manufacturing corporations. In the latter case some concern themselves only with their own product, some with all the materials they purchase, and some have departments adapted solely to research into the properties of materials, applying the results to their factory practise. In all the large centers of population and manufal'turing are to be found, laboratories where the needs of commerce for the testing of materials can be met. The same great variety of substances and fabrics are submitted to the chemists and physicists on their staffs, who are frequently appealed to for the decision of important questions. Yet in the application of material testing to the industries one meets at times a marked indiffprenee to its economic advantages. Thi& is the more curious since there are so many' cases where they are obvious and so many where successful manufacturers testify to the importance to them of upholding this arm of efficiency. They know that in many raw materials entering into. the manufacture the presence of an adulterant or an inel't substance carries a greater penalty than the mere payment for the useless element. The factory ·and handling charges accumulate. against it just as if it was a valuable element and the output of finisher material is reduced. If, for example, one wishes to neutralize acid solutions with lime and employs an impure lime instead of a pure one, he will use more of it and he will be obliged to dispose of more sludge, possibly carrying with it absorbed valuable substances. If one uses a coal whose fuel value, measured in heat units, is less than that of a coal used by a competitor, he will likely feel the difference, not alone in his coal bills, but in his labor items, for stoking and for disposal of refuse. The manufacture of silk fibrics furnishes another example. One would think that any manager using in large quantities as his chief raw material a substance more costly per pound than coal is per ton would 'e solicitous to keep exact record of the mois t ure in the lots he would buy that he might know their abso. lute dry weight, or “conditioned weight,” so called. Yet in the case of raw silk as used in this country we see something remarl{able. 20,363,327 pounds, worth $65,424,784, were imported into this country in 1909-1910. Special trains flew across the continent at high speed to bring the Japanese importations from San Francisco to New York city. So valuable was this raw material that a gain in interest and insurance was made by this haste. Yet only 1,298,709 pounds were officially “conditioned” for moisture or examined for other non-silk substances at the silk association's laboratory in New York city during the same period. Of course some silk manufacturers have their own silk conditioning laboratories, but they are very few. Moreover, these figures are confronted with the statistics of conditioning in Europe whose consumption of raw silk is rapidly being approached by that of Amelira. In the Milan conditioning house in (ConUnuca nn po,ac ZM.)