To avoid the first cost of a big power plant, the expensive copper conductors, the difficulties of the third-rail or jumping trolley, and the chance that a broken steam pipe may disable a whole line, and to combine the efficiency of the gasoline engine with the continuous torque of the electric motor, the gasoline-electric locomotive has been proposed. A powerful gasoline engine and dynamo are mounted on a car whose trucks are fitted with motors to take the dynamo current. Thus the power house travels with the train and the tracks are not used as conductors.

This system, with the steam engine as prime mover instead of the gasoline motor, was first employed by Heilmann in France, and is being extensively used in Switzerland. The General Electric Company is building a 200-horse-power locomotive of this type at Schenectady and a still larger one is under construction, according to The Manufacturer's Record, for the Southern Pacific Railroad, the prime mover in this last case being that most efficient of all oil engines, the Diesel motor. Great things are expected from this combination since it seems to possess the good points of both systems. Of course the acceleration on starting will not approach that of the New York Central locomotive; for the combination motor begins its travel with zero current and not with the full pressure from the third-rail.

Invar. It is a matter of common knowledge that most substances grow larger with an increase of temperature, gases gaining most in volume, then liquids and next solids, and among solids the metals are the most expansible. This property has been put to good use, scientific and ordinary, in many ways, but in many instances too, it is troublesome and considerable ingenuity must be exercised to neutralize its effects.

A metal measuring rod or tape will give results too small or too great as it grows warmer or colder. The time of swing of a pendulum depends on the length of the rod; if the time of swing of a seconds-pendulum be lengthened or shortened by one-thousandth of a second, and that surely is very little, the clock it regulates will lose or gain nearly one minute and a half in twenty-four hours. An increase in the length of a secondspendulum of one-tenth of an inch means a loss of nearly two minutes daily. A brass rod for such a pendulum could easily suffer one-fifth of an inch elongation during the change from winter to summer temperature, which would mean a variation of four minutes daily.

Of course, wood, with a much smaller coefficient than metal, may be employed; but if metal must be used, corrections may be applied, and expansion used to neutralize expansion automatically. If, however, it could be done away with or rendered inappreciable, much worry would be avoided. Professor Guillaume, of Paris, comes to the rescue with Invar, an alloy which has received the short name to avoid the periphrase "steel containing about 36 per cent. of nickel which is characterized by possessing an extremely small coefficient of expansion, or by the fact that its specific volume is practically invariable when considered as a function of the temperature." One very curious property of some of the nickel steel alloys examined, is the fact that though composed of two magnetic elements, some of the compounds were not themselves magnetic except under certain conditions, and further investigation showed a relation between their magnetic properties and expansion.

In an article in Nature, December 8, 1904, Professor Guillaume describes some applications of Invar and its fellows. In geodetic survey work,

usually one line most accurately measured serves, with angle determinations, as the base for computing other and inaccessible lines. Here the 36 per cent. nickel alloy or true Invar is invaluable. Instead of short measuring bars of ordinary metal packed in ice to keep the temperature constant, a long uniformly stretched wire of Invar may be used. A five degree Centigrade variation makes a difference of scarcely one in one million, about one-third of an inch in five miles.

The same alloy makes a pendulum rod which, uncompensated and under constant pressure, will not vary more than two seconds in twenty-four hours. Watches gain or lose because, to omit other reasons, their springs change in elasticity with varying temperature; a 24 per cent. nickel alloy will obviate the necessity of costly compensation.

One of these compounds is also used in the manufacture of incandescent lamps. The current for lighting the common Edison lamp passes to the carbon filament through the glass, by means of platinum wires fused in the glass itself. Platinum has been always used because its coefficient of expansion is about the same as that of glass; that is, both expand and contract the same amount, so after the "fusing in" the platinum in cooling does not shrink away from the glass and crack it, as would be the case with other metals. Platinum is very expensive and at the same time is most useful for other purposes. One of Professor Guillaume's nickel-steel alloys, 45 per cent. nickel will answer just as well as platinum and is much used now by some makers under the name of platinite.

Nitrogen Fixation.-We learn from text-books that there is no fact in plant physiology which has been more firmly established than that all plants must have nitrogen in order to thrive and that under normal conditions this nitrogen must be obtained through the roots in some highly organized form. The practically boundless supply of nitrogen in the air, about four-fifths of the bulk of the atmosphere, is beyond the direct and immediate reach of plants.

Millions of dollars' worth of available nitrogen is swept off to the ocean, through the world's sewers, every year; the great sodium nitrate beds of Chile and Peru will be exhausted in probably forty or fifty years; the rich guano deposits of sea-coast and sea-island have almost disappeared, while the ammonia bye-products of coal distillation are still obtained in rather insignificant quantities. So agricultural chemists and scientific farmers are looking about for some means of enriching the failing sources of nitrogenous

manures.

Many years ago it was noticed that certain land, if allowed to lie fallow for a considerable length of time, would gain in nitrates without any visible addition having been made. It is now certain that one of the principal agents in this nitrogen increase is a group of soil bacteria which have the power of fixing the air nitrogen and preparing it for plant food. Two German investigators isolated and cultivated these organisms artificially.

This bacteria culture, called nitragin, put on the market a few years ago was used in two ways, being applied directly to the fields, or mixed with water and brought into contact with the seed before sowing. This nitragin was adapted to only a few crops and its use met with varying success. Its manufacture was abandoned mainly because it could not stand delay in transportation without losing at least 80 per cent. of its strength.

The Scientific American, February 18, states that Dr. George T. Moore. of the U. S. Weather Bureau, has secured a patent on a method of making

cultures of nitrogen-fixing bacteria and of drying them so that they may be sent all over the world while at the same time their activity is indefinitely preserved. The nitragin treatment may prove quite successful.

Several electrical processes have been devised for the direct combination of the nitrogen and oxygen of the air, resulting finally in the production of nitric acid. Cheapness of manufacture is the main object, and fair results have been obtained.

A new substitute for sodium nitrate and ammonium sulphate is now announced in the Electrical World, February 4, bearing the name of calcium cyanamide, a compound of calcium, carbon and nitrogen. It has been tested for three years at the royal agricultural testing stations of Darmstadt and Posen. It is expected to be a much better fertilizer than the other substances as it contains not only nitrogen but lime. Works are being built at Piano d'Orta, in Italy, which will be able to produce 4,000 tons a year. The manufacture is said to be simple, consisting in drawing a stream of air over lime and carbon heated under certain conditions.

The Cost of High Speed.-High speed railroading, according to the Electrical World and Engineer, February 4, is waiting for electricity. "Is it seemly that smelly little automobiles should rip off miles in 35 to 40 seconds over a sandy beach, while engineers hesitate at a similar speed over a smooth track, backed by an entire power station?

The mile record and the miles-per-hour record belong to the gasoline propelled automobile which has reached a 113 mile rate. But will such speed with heavy cars on a commercial line require "the backing of an entire power station" or rather the backing of a millionaire's treasures?

The Zossen experimental work in 1902-03 showed the possibility of high speeds with safety, even up to 131 miles per hour, if proper precautions be taken. The cars must be heavy, for above an 80-mile speed, the slight unavoidable irregularities of even a well laid track would tend to make a light car leave the rails, while at higher speeds the lateral oscillations become so great that no curve with a radius less than a mile is permissible. The road-bed and the running equipment will be expensive, and the power cost is beyond a doubt. For one 100-ton car of 60-seat capacity, a speed of 110 miles per hour called for 1,300 horse-power, and this was increased to 2,000 horse-power when the 'speed reached 120 miles. At this velocity 55 per cent. of the power, or 1,100 horse-power, was absorbed in overcoming the air resistance alone.

The Electrical Review, February 11, tells us that there is considerable discussion in Germany at present as to building a high speed road between Berlin, the capital, and Hamburg, the principal seaport, to supplement the existing very fair steam railroad service.

Propositions have been received by the government for single and doubletrack roads, the distance being about 175 miles. A single-track road for a speed of 90 miles an hour, would cost $17,000,000; a double-track line for a 100 mile speed demands $30,000,000, and if 125 miles per hour be looked for, the road-building expense amounts to $36,000,000. This last figure means about $206,000 to the mile.

Such a road must rely on passenger traffic for its revenue, and to make it pay it should transport 850,000 passengers yearly, about 2,800 for each business day. The time saved would amount to, at most, two hours. One good authority says, it is now well understood that the limit of physical and nervous endurance is closely reached on steam locomotives, for the engine

drivers, of course, with line speeds of 60 to 75 miles per hour. Is a regular high speed service worth the money and the risk?

Municipal Ownership.-It has been announced that an experimental plant will be installed by the municipality of New York, to furnish current for lighting the new Williamsburg Bridge, connecting the boroughs of Brooklyn and New York. It is proposed to run the electrical plant in combination with a refuse destructor. The combustible material gathered by the street cleaning department is to provide the power instead of being thrown into the sea.

This project may develop into a city plant for general public lighting, on account of the charge that New York is paying excessively high rates to private companies for electric service. Some of the New York papers have been urging on the Mayor and the Comptroller by the clamorous testimony of their " expert" reporters, thereby showing their interest in the true welfare of the city, and incidentally keeping themselves well in the public eye and reaping the financial reward of political virtue at two or three cents a copy.

The more temperate of the daily papers and the technical press in general are against the project, and their opposition seems to rest on the principle of individual effort as against paternalism, and on the contention that the system of municipal ownership has not proved itself financially sound.

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A private plant must pay; a public plant will always pay those that are running it, but it need not pay those that pay for the running. Accounts and financial reports may be cooked" so as to present a most inviting appearance, the minus signs being skilfully changed to plus, by deftly extracting the needful material from the taxpayer's pocket on the plea of general expense. The figures that really talk in a matter of this kind are not figures of speech but figures of bookkeeping.

Municipal ownership has existed for some years throughout England, and according to general statements, has been a great success. The Electrical World and Engineer, February 4, presents an article by Mr. Schooling, who as an economist merely, and without business bias, has tabulated the financial results of some 300 English town corporations in business with an average of three and one-half undertakings" apiece.

The total capital invested was $605,850,000; the yearly profit on every $500 capital amounted to 75 cents, and this was got by allowing a yearly depreciation of only 77 cents on $500, instead of the more reasonable sum of $22.50. The total yearly depreciation allowed on the books was $966,370 instead of $30,292,500. This is a choice example of "cookery."

Electricity and Bread.-The modern superfine wheat flour is still too dark for the Parisian; so electricity is asked to whiten it. The flour is exposed to the action of ozonized air, air whose oxygen has undergone some apparently molecular change under electrical influence, and ozone, as we know, is an energetic bleaching agent.

A report to the Academy of Sciences of Paris, on ordinary flour and "treated" flour, states that the latter is much whiter in color but that its taste and odor are far inferior to the taste and odor of ordinary flour. The amount of phosphorus is the same in both, but the quantities of fatty and acid substances vary largely, and the gluten is discolored and changed in the ozonized flour.

The bread made from this flour is much whiter than usual, but of far inferior taste. Like many surgical operations the electrical treatment is eminently successful, but the flour cannot stand the shock.

EDUCATION.

President Harper, of Chicago, has issued twelve addresses to his students under the title of The Religious and Higher Life. He confesses to an increasing difficulty in dealing with religious subjects before his university. That was to be expected, for he has no authority to stand on. It is a comfort to hear him say, however, that "an institution which does not possess a strongly pronounced religious spirit may do as much harm as good." Instead of as much he should have said "more."

The School of Journalism, which Mr. Pulitzer was to found, is not to be established, at least not now. The projector of the scheme is not certain that the time is fully ripe or the editorial profession fully ready for the project, and the Indispensable Man to be at the head of it has not been found. However, Mr. Pulitzer has already put a million in the hands of Columbia, and another million is to be at its disposal immediately on the death of the donor.

In the Educational Review of February, 1905, a writer on "The American Rhodes Scholars at Oxford" gives us the impression that the Dons over there are rather grumpy over the arrangement which, by the admission of Americans keeps out the students of the British Isles. On the other hand, what is most distasteful to a majority of the American students is "the traditional discipline of the colleges; they are treated as inexperienced boys, work with tutors at their elbows, are subjected to watchful surveillance, and are fined and disciplined if they are outside the gates after certain hours; but there is no evidence that they are seriously irritated or annoyed; though they describe the colleges as kindergartens for adults, or as academic nurseries with awkward tutors and ugly proctors in place of governesses and housemaids." The writer is of the opinion that the experience will "help to soften the asperities of American manners," and that "the Englishman shivers when he hears the American nasal twang in the quadrangles." Perhaps our selfappreciation will be benefitted by this out-spoken admission.

Father James Conway, S.J., Professor of Philosophy at Fordham, who has written so extensively and so well on the school question, appears in the February number of the Educational Review with the statement of the Catholic position on the question of education. Very likely much that has been pointed out on that very vital topic has never been put under the eyes that will read it in that magazine. It is in Father Conway's clear and exhaustive

manner.

President Thwing informs us in the North American Review of February that a committee of the Faculty of Arts and Sciences of Harvard reports that "the average amount of study by college men is discreditably small."

Twenty-six hours a week ought to be the time devoted to scholastic work, but the figures concerning seventeen hundred men show that few spend not over one hour a week in preparation for a course of three hours, and that a few devote to preparation between seven and eight hours. The number who spend between one and two hours is forty times greater than the number who spend not over one.

President Thwing is not shocked.

Universities are not institutions, he says, which oblige men to toil; they are opportunities. Still even Lord Roseberry laments his wasted opportunities. "They are not only opportunities but experiment stations, where theories may be discussed and applied; they