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It may be worth noting that the minimum time in the first table is 2 h. 35 m., and the maximum in the second 3 h. 35 m. Now by referring to the fifth column, we see that the Gramme deposited 21-10 02., and the Wilde 16-52. The last column shows in the one case a speed of 300 revolutions per minute, and in the other 2,400. The times are as l to 1425, the velocities as l to 8, and the decomposed electrolytes as 1 to '782. Remembering that the advantage is inversely as the time and velocity and directly as the deposits, we find in this particular case a resultant ratio of 11 to 1. By analysing the other data in a similar manner, we obtain a ratio of about 8 to l in favour of the Gramme.

But little attention has been as yet devoted to other electrochemical problems, and we are not sure that such a trial would not lead to satisfactory results. We are glad to know that a large machine is now constructing by Messrs. VVhieldon and Cooke, with which M. Werdermann intends to approach the subject. Among other things, he proposes, 1st, to purify iron by passing off the phosphorus and sulphur into the slag; 2ndly, to obtain aluminium from the double chloride of aluminium and sodium ; 3rdly, to deposit copper directly on iron in the “ dry way ;” 4thly, to convert by a direct process chloride of sodium, or common salt, into caustic soda. If he succeed in his undertaking, as we sincerely hope he will, a considerable reduction must take place in the market price of some of our metals.

There is yet another department to which this invention may be usefully applied, viz. the illumination of lighthouses. The machines used for that purpose are those made in France by the Alliance Company, and in England by Professor Holmes. This beautiful piece of science and skill is, however, inferior in several respects to the Gramme. It takes up nearly four times

101.. KIL—NO. XLVIII. 'r v

as much room, produces but half the light for the same motive power, and for the same brilliancy of light is twice as expensive.* During the last two months the electric light has been exhibited from the Clock Tower, Westminster, in competition with Mr. Wigham’s gaslight, the design of the Board of Works being to adopt that which will answer better as a signal light for the House of Commons. The machine is fitted up in the engine-room under the Peers’ lobby, whence the conducting wires—425 in. in diameter—leading from the terminals, are carried up to the lantern, a distance of 900 feet. Here the current is admitted into a Serrin’s regulator, and the light is projected by one of Chance’s holophotes in a beam of parallel rays.' By a very ingenious contrivance, devised by Mr. Conrad W. Cooke—to whom the electrical arrangements on the Clock Tower have been entrusted—this pencil may be directed into any azimuth or angle of depression lying between certain fixed limits. This is effected by a horizontally-placed rotating-table, movable on a central pivot by means of a worm and worm-wheel. A second table is joined with the outward edge of the first, while the other may be raised or lowered by a vertical screw of considerable play. On this is adjusted a ' little trolley, on which two regulators are fixed, the whole being susceptible of a reciprocating movement, which is, moreover, so arranged that when one regulator is out of use, the other is brought into the focus of the holophote, and at the same time into connection with the machine. This latter is effected by providing each regulator with a pair of underlying metallic strips, which press upon a pair of copper studs in electrical communication with the polar terminals. The object of this arrangement is to prevent any sensible interruption in the light when, by their consumption, it becomes necessary to change the carbons. These are 8 in. long and 3} in. square; they last about four or five hours. At the end of that time, a slight rectilinear movement is imparted to the small rollingtable, and the second lamp comes into position. As this may be done very rapidly, the discontinuance in the light is scarcely perceptible.

On Monday night, May 26, we had, in company with several other gentlemen, an opportunity of judging of the intensity of this light. The coils of the machine were driven at a speed of 300 revolutions per minute, and the light emitted was estimated equal to that of 8,000 candles. The emergent rays formed a bright silvery beam, which reminded one, says a contemporary, of the lustrous appearance of Donati’s comet when in perihelion. At Trafalgar Square, a black shadow of the pillar

' “Engineering.” April 95, 1873.

was thrown upon the dome of the National Gallery. At the Duke of York’s Steps, a very striking effect was produced by the sharp, well-defined shadows of trees and their foliage cast on the pedestal of the shaft and column. As we made no photometrical observations of the relative intensities of the gaslight and the electrical beam, we can merely record our impression, which to many may seem a rhetorical superfluity, that the latter was greatly superior to its fair rival in point of brilliancy. The one was dazzling and penetrating; the other, soft and comparatively feeble.

From the preceding pages, it must strike every one that the Gramme machine is unquestionably among the greatest inventions of our age. It would be premature to speculate as to what it may yet achieve, but the experiments detailed in this paper encourage the expectation of still greater results when its intrinsic merits becoming generally known and appreciated, will have secured it its fitting place in the practical applications of electricity.

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HE mental faculties of birds are admitted to be greatly inferior to those of the higher quadrupeds, and such is the case no doubt ; but, irrespective of their remarkable instincts, they display other mental qualities of no very mean order. These we shall now consider individually, along with their accompanying gestures and utterances, so that the reader may consider how far they allow of being associated with, for example, the instinctive impulses that prompt the bird to migrate, or other well-known phenomena in relation to their nests and habits.

In the first place certain mental powers in birds, as in higher animals, are improved by exercise, and many species and even individuals of the same species show a greater aptitude than others. Even instincts which are considered to be uninfiuenced by teaching or example do often display variations expressive of both reason and judgment, whilst many acquired habits lapse after generations into instinctive actions. Fear is a good instance of an instinctive emotion which has been greatly strengthened by experience, and it is wonderful to observe the part man has played in increasing it in many birds. Let us compare the delineations on ancient Egyptian monuments, showing the fowler surprising flocks of water-birds among the tall papyrus swamps of the Delta, and dealing destruction among them by means of missiles made of small pieces of wood shaped like the letter S, and delivered with force and dexterity, with the practice now adopted, where, after all the caution possible, and aid of gunpowder, it is extremely difficult to get within even rifle range of such as the geese and ducks. But although these birds are much persecuted, there are others which contrast in this respect in a singular way with their brethren in other countries. The fearless habits of the kestrel of Egypt, as compared with its much oppressed brother in England, are notable. No one molests it, and in the days of the Pharaohs, as we learn from Herodotus, it was held sacred to the extent that whoever killed a hawk was put to death ;* so that it is possible the kestrel of the Lower Nile may have continued to enjoy a feeling of security up to the present day. The hooded crow is also very tame, as compared with its harassed brother in many other countries. The school-boy knows the effect produced by the report of his gun on many birds, and how other senses become sharpened in consequence; to wit, perception, as evinced by the crow and magpie perceiving the dreaded implement of destruction long before it can be brought to bear on them. Many birds acquire fear slowly; others are naturally timid. All gallinaceous birds are more or less fearless in their primordial states; and even partridges and grouse, only after weeks of constant persecution, acquire the alertness to enable them to be up and off before the sportsman gets within range. Even this lesson is forgotten during the close season. I was surprised both in the Himalayan and Canadian forests to find certain pheasants in the former and partridges in the latter quite fearless, more especially in secluded districts where they had not been molested by man. Indeed, so indifferent of danger were they, that beyond flying from the ground into the nearest branch, they seemed quite regardless of our presence. It was, moreover, a common practice with the first European settlers in many parts of America to knock the partridges off their perches by means of long wands. Then the only enemies of these birds were the sable and other martens, and the lynx, from which they escaped by simply flying into the nearest tree ; however, as clearings were made, and the birds became more molested by man, they gradually took to longer flights, so that around the settlements it is somewhat difficult- to shoot them. Birds that frequent mid-ocean islands, and have few enemies, are generally very tame. Such, however, as the grebes, guillemots, and awks, are low in the scale of ornithic intelligence; and probably on this account, and from its inability to fly, we might ascribe the extinction of the celebrated Northern Penguin or Great Awk, which may now be said to have disappeared, at all events from explored portions of the globe. Again, the beautiful feathers of the monal pheasant of the Himalayas and American crested-jay have been long in request to decorate the heads of the ladies of Europe and North America ; and, in consequence of constant persecution, both species have become so wild and wary, that in the case of the latter the denizens of the forest solitudes have inherited the timidity of their brethren 0f the settled districts. Here, no doubt, fear gradually attained has become a trait of character, seeing that

" “Euterpe,” II. para. 65. The Ibis is also included; it is now extinct in Egypt.

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