'July 4, 1890.] 



SCIENCE. 



Kew Bulletin, "two companies were formed for working it; and 

 , at the present time there is a company in London which deals ex- 

 clusively in this article, a sample of which is in the Kew Muse- 

 ums. It is claimed for this tea that it has many advantages over 

 loose tea, the chief of which is, that, the leaves being submitted 

 to heavy hydraulic pressure, all the cells are broken, and the con- 

 stituents of the leaf more easily extracted by the boiling water, 

 thus effecting a considerable saving in the quantity required for 

 use. Its great advantages over loose tea, however, would seem to 

 be its more portable character; and in the case of long sea-voyages, 

 or for use in expeditions, the reduction of its bulk to one-third. 

 The compression of tea into blocks, further, it is said, constitutes 

 a real and important improvement in the treatment of tea. These 

 blocks weigh a quarter of a pound each, and are subdivided into 

 ounces, half- ounces, and quarter-ounces. This insures exactitude 

 in measuring, and saves the trouble, waste, and uncertainty of 

 measuring by spoonfuls. It also insures uniformity in the 

 strength of the infusion. By compression it is claimed that the 

 aromatic properties of the leaf are retained for a much longer 

 period, and that it is better preserved from damp and climatic 

 changes." 



— In accordance with an agreement between the American 

 Society of Mechanical Engineers and the American Institute of 

 Electrical Engineers, the headquarters of the Institute of Electri- 

 cal Engineers will hereafter be at the house of the Mechanical 

 Engineers, 13 West 31st Street, near Fifth Avenue. Communi- 

 cations and exchanges should be addressed accordingly. 



— A paper on the Mannesrnann weldless tubes was lately read 

 before the Society of Arts, London, by Mr. J. G. Gordon, the chair 

 being occupied by Sir Frederick Bramwell, who referred to the 

 importance and interest of the subject, and to the extraordinary 

 mieans by which the desired result was attained. The process, 

 according to Nature, consists in the solution of a purely kinemat- 

 ical problem; viz., the arranging of the velocity ratio of a pair of 

 aconoidal rolls so as to change a solid piece delivered to them at 

 one end into a hollow tube passed out at the other. These rolls 

 revolve at about 200 to 300 revolutions per minute, and, by their 

 action on the hot and therefore plastic steel, stretch it, and make 

 a hollow in the centre. The substance of the metal must be suffi- 

 ciently homogeneous and plastic; and in passing through the 

 rolls it undergoes a violent twisting and stretching action. The 

 bar, in fact, in its passage through the rolls, is twisted as a thread 

 is twisted in a spinning-machine, the material being drawn from 

 the interior. This action was illustrated by one of the exhibits, 

 which consisted of a bar, the ends of which were slightly drawn 

 down under the hammer, so that the rolls could not act on them. 

 A hollow was thus produced in the solid bar of metal, the con- 

 tents of which were tested by Professor Finke of Berlin, and found 

 to contain 99 per cent of hydrogen of its total volume. The re- 

 maining 1 per cent he considered to be probably nitrogen. In 

 the carrying-out of the process, 2,000 to 10,000 horse-power is re- 

 quired for from 30 to 45 seconds, according to the dimensions of 

 the tube. Although this is all the time actually required to con- 

 vert a bar 10 to 12 feet long and 4 inches in diameter into a tube, 

 a certain amount of time is required to adjust the guide?, to de- 

 liver the bar to the rolls, and to remove the finished tube. The 

 time so spent is employed to accumulate energy in a fly-wheel 20 

 feet in diameter, weighing 70 tons, and revolving 240 times in a 

 minute, the periphery of which, therefore, revolves at 2.85 miles 

 per minute. By this means a steam-engine of 1,200 horse-power 

 is quite sufficient to do the work. A peculiar feature of these 

 rolls is that the resulting tube is a test of the material and pro- 

 cess. If the metal is homogeneous throughout, and well melted, 

 well I'oUed, and carefully heated, it makes a perfect tube; but if 

 there is a flaw in the metal, or if it has not been properly heated, 

 the rolls cannot make a tube out of it. The paper, which was 

 illustrated by photographs of the mills and engines, led to a very 

 interesting discussion, in which Sir Frederick Bramwell, Professor 

 A. B. W. Kennedy, Mr. Alexander Siemens, and others, took part. 



— In France much interest is being taken in the question 

 ■whether a university shall be established in Paris. At a meeting 

 of the general council of the Paris faculties, held June 14 at the 



Sarbonne, it was agreed that a university with five faculties 

 (Protestant theology, law, medicine, science, and literature), and 

 an upper school of pharmacy, should be formed. "The principal 

 effects of the constitution of the university," says the Paris cor- 

 respondent of the London Times, "will be to permit the faculties 

 to make arrangements for the organization of instruction (under 

 the foi-m of schools or institutes), of which the elements are at 

 present scattered in several faculties, and to facilitate a sort of 

 general instruction of a philosophical character, to which the pro- 

 fessors of all the faculties will contribute, and which will be ad- 

 dressed to the students. The university will grant, besides pro- 

 fessional degrees, diplomas of purely scientific studies to native 

 and foreign students. " 



— The steam-loop is an appliance for returning to a steam-boiler 

 the condensed water from steam pipes, jackets, heating-coUs, and 

 the like. It is a striking piece of apparatus, since it will re- 

 turn water to a boiler situated at a higher level, without the inter- 

 vention of pumps, injectors, or other motors. The water, accord- 

 ing to Engineering, simply flows back just as if it were under the 

 action of gravity, the only means of communication being a range 

 of pipes. The action will be readily understood by reference to 

 the annexed diagram, which shows a steam-boiler connected by a 

 steam-pipe from the dome A to a, steam-engine B. Immediately 

 in front of the engine is fixed a separator, which catches the water 

 carried over by the steam, as well as that which condenses in the 

 pipe. From the bottom of the separator there rises a pipe until 



it attains a considerable elevation above the water-line of the 

 boiler; it then proceeds horizontally, and finally descends, and 

 enters the boiler at D. The water from the separator follows the 

 course of the pipe, and flows into the boiler at a higher level than 

 the separator. The reason of this will be readily seen. The 

 steam-pipe and the steam-loop are both connected to the boiler; 

 but of course there is a slight difference of pressure in them, 

 the pressure falling a little the farther the steam gets from the 

 boiler. Let us suppose the pipes to be blown through at 

 the cocks S and 0, and these cocks then closed. Water will 

 cornmence to collect in the separator, and the pressure in the 

 loop to fall by reason of condensation. The excess of pressure in 

 the separator will immediately begin to drive the water up the 

 riser, not in a solid body, but in separate plugs or plungers, which 

 will follow each other at frequent intervals. As soon as these 

 reach the top of the riser, they will flow along the horizontal 

 pipe, which is of large diameter, and collect in the down pipe. 

 Here the mass will remain until the head of water, plus the steam- 

 pressure above it, is sufficient to raise the check- valve, when a 

 part of the column will flow into the boiler. Usually a head of a 

 few feet is sufficient to effect this ; but. if the pipes be very long, it 

 may require twenty feet or more. At the moment when the check- 

 valve lifts, the gauges at £J and J^ will give the same reading, 

 while the gauge at G will show the sleam-pressure existing at that 

 point. The water is thus returned to the boiler without loss of 

 pressure, and almost without loss of heat. This is done continu- 

 ously and automatically, the only care required being to blow- 

 though occasionally to remove the air. 



