It is in these circumstances that our Legislature, at the instance of a benevolent President, decides to refund to the people of the island two million dollars of duties collected in our ports on their products. Our tariff system breeds poverty in the population it oppresses, and then we rush to their assistance with a largess. They ask for justice and we offer them alms—alms for which the correspondent already quoted says he can not find a single individual who is grateful. We rob the Puerto Rican Peter to pay our own tobacco-growing Paul; and then we rob the whole community in order to pay back Peter. And, strange to say, some of us feel very virtuous over the business. The countenance of the President glows with satisfaction over the thought of all the good he is doing. For our part, we view the matter in a different light. The money will, of course, meet certain expenses of government in Puerto Rico; but there is reason to fear that it will do as much to pauperize the island in one direction as the restriction of its trade will do in another. What the Puerto Ricans want is not alms, but commercial liberty. The repayment of this money will not stimulate their trade; it will not stimulate anything except their helplessness. It is an open question whether they will suffer more by our protectionist greed or by our wishy-washy sentimentality. Meantime what are we to think of the party system whose exigencies place us in so ridiculous a position before the world? How long shall it abuse our patience?
Fragments of Science.
Ventilation of Tunnels.—The question of the ventilation of tunnels forms the subject of a series of articles, by M. Raymond Godfernaux, published recently in Le Génie Civil. The principal sources of definite information, upon which the discussion of M. Godfernaux is based, are the reports of the committee on ventilation of tunnels of the Metropolitan Railway of London, and of the commission appointed by the Italian Minister of Public Works to investigate the tunnels of the railways of the department of the Adriatic. Although the vitiation of the air in a tunnel may proceed from three sources—i. e., the lighting, the respiration of the passengers, and the combustion of the fuel in the engines—yet the two former sources are insignificant compared with the latter, which alone need be considered. The principal products of combustion which are injurious are carbonic acid, carbonic oxide, and sulphurous acid. Of these it is found that the proportion of carbonic oxide should not exceed 0.01 per cent, which corresponds to 0.13 per cent of carbonic acid in excess of the normal proportion of 0.03 per cent and to 0.00027 per cent of sulphurous acid. In practice it is found that if the total proportion of carbonic acid be limited to 0.15 per cent the proportions of the other gases will be well within the comfort and danger limits. This is much lower than is often attained in crowded auditoriums, where the proportion of carbonic acid sometimes reaches 0.4 to 0.5 per cent, but in such cases there is no carbonic oxide produced, while in the case of tunnels traversed by steam locomotives we may assume that the carbonic oxide will be about 1 to 13 of the carbonic acid, and the sulphurous acid about 1 to 440. Assuming a given limit of deterioration of the air, it would be easy to devise a system of ventilation if it were possible to treat the tunnel as if it were a closed room or controllable space. In practice, however, the conditions are peculiar. The space to be ventilated is a long, narrow passage, usually open only at the ends, and traversed periodically often almost continuously, by trains in one or both directions, these trains emitting the objectionable gases and also disturbing the air currents best adapted to proper ventilation. How best to reconcile these conflicting conditions forms the problem under consideration. Where there are but few trains it has been proposed to close the ends of the tunnel by doors, and provide a fan exhaust or pressure system, but this method is obviously limited in its applications. The practical conditions which must be considered are those in which frequent trains in opposite directions pass through the tunnel, and these conditions M. Godfernaux has analyzed graphically in a very interesting manner. Assuming a double-track tunnel eight hundred metres (a metre contains 39.37 inches) in length, with an exhausting ventilator placed in the middle and with trains of a given gas-producing capacity passing on each track every three minutes, he constructs a diagram showing how the composition of the atmosphere of the tunnel varies at successive points, and how, by an examination of the diagram thus made, it is possible to discover the maximum vitiation of the air, and consequently the extent to which the conditions are satisfied. By one or two such constructions any such problem may be solved to a degree quite within the limits of practical work, and the effect of various systems of ventilation compared. M. Godfernaux discusses various systems of ventilation, including those involving the use of shafts, fan blowers and exhausters, and air jets, and concludes with a description of the Saccardo system, in use in the Apennine tunnel of the Bologna-Pistoia line, and to the St. Gothard Tunnel. While all this investigation and discussion is of much value, it certainly seems as if the true remedy lies not so much in the removal of deleterious gases as in the absence of their production. The substitution of electric traction avoids altogether the fouling of the air of tunnels and subways, and electric locomotives are already used in the Baltimore Tunnel in the United States and elsewhere, and it seems as if this remedy is the true one to be applied in all cases.
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Liquid Air.—The following warning appears in The Engineering and Mining Journal of March 3d: “The advertisements which are now appearing in the papers all over the country of companies which are to furnish liquid air on a large scale must be accepted with a great deal of caution. The public mind has been very adroitly worked up for the reception of these by lectures, paragraphs in the press, and other well-understood methods. Undoubtedly liquid air possesses some valuable properties, and many striking experiments can be performed with it. It is not by any means certain yet that it can be prepared, transported, and used economically on a commercial scale, or that the difficulties in the way have been overcome. We do not say that they may not be overcome in the future; but to talk, as the advertisements do, of the certainty that liquid air will soon largely replace steam in furnishing motive power is going entirely too far. Such assertions have no present basis of fact to warrant any one in making them. The liquid-air people have a great deal to do yet before they can establish their claims or carry on business on a scale that will warrant the organization of ten-million-dollar companies. The question of validity of patents is also quite an open one. It is doubtful if there is any valid patent on this subject.”
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Taka-Diastase.—The following is taken from an interesting article, by W. E. Stone and H. E. Wright, in The Journal of the American Chemical Society: “Taka-diastase is, so far as known, somewhat similar to malt-diastase in its chemical character, viz.: a highly nitrogenous substance, readily soluble in water, and dependent upon certain conditions of temperature for its maximum activity. Its action is also affected by alkalies and acids. It is produced as the result of the growth of a species of mold (Eurotium oryzæ, Ahlberg) upon rice, maize, wheat bran, etc. For its production, as at present practiced in this country, wheat bran is steamed and, after cooling, is sown with the spores of the fungus. After twenty-four hours in culture rooms, at a temperature of about 25° C., the fungous growth becomes visible. In forty or fifty hours the content in diastatic material has reached the maximum, and further growth of the fungus is checked by cooling. The material, now consisting of the bran felted together with fungus mycelium, is called ‘taka-koji.’ It may be mixed with grain or starchy materials in the same manner as malt is used, and, like malt, will speedily convert the starch into fermentable sugars. An aqueous extract of the mass may be used for a similar purpose. For the preparation of a pure product, which, however, is not necessary for ordinary industrial purposes, the aqueous extract is concentrated by evaporation, and on the addition of alcohol the diastatic substance may be precipitated as a yellowish powder, easily soluble in water, of stable keeping qualities, and possessed of an unusual power of converting starch into sugar. The medicinal preparation above mentioned is obtained in this way, and represents a fairly pure form of the diastatic principle. This bears the name of ‘taka-diastase.’”
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Professor Agassiz’s Investigations on Coral Islands.—Having steamed and observed for twenty-five hundred miles among the Paumotu Islands, Prof. Alexander Agassiz says, in a second letter from the Albatross Expedition, published in the American Journal of Science, that he has seen nothing tending to show that there has anywhere been a subsidence, but that the condition of the islands does not seem to him capable of explanation on any theory except that they have been formed in an area of elevation. All the islands examined are composed of a tertiary coralliferous limestone, which has been elevated to a greater or less extent above the level of the sea, and then planed down by atmospheric agencies and submarine erosion, and the appearance of this old rock is very different from that of the modern reef rock. In these islands the rims of the great atolls, after having been denuded to the level of the sea, are built up again from the material of their two faces, so that a kind of conglomerate, or breccia, or pudding stone, or beach rock is found on all the reef flats. On the lagoon side sand bars grow into small islands and gradually become covered with vegetation. Whenever the material supplied from both sides is very abundant the land ring becomes more or less solid; the islets become islands, separated by narrow or wider cuts, until they at length form the large islands, which seem at first to be a continuous land around the rim of the lagoon, while they are often really much dissected. In time water ceases to pass through the channels, and only the marks of them are left. Few if any of the lagoons appear to be shut off from the sea as Dana and other writers have supposed. They simply have not boat passages. Unlike other coral regions, the Paumotu reefs seem to bear only a scanty life.