KIDD'S LONDON JOURNAL. 



85 



too, has been used as a source of power. It is 

 to be hoped, however, that the steam-engine will 

 ultimately everywhere supersede the employment 

 of man as a means of mere animal strength; and 

 enable him to limit the exercise of his muscular 

 power to those cases where tact, skill, delicacy of 

 adjustment and adaptation to varying circum- 

 stances, are required — where the superior power 

 of an intelligent being, which no machine can 

 imitate, is called into play: in short, that man 

 shall cease or abate the direct exercise of brute 

 force, and employ himself in the higher operation 

 of guiding and controlling it. 



This power is not made use of in the steam- 

 engine ; but the power of an engine is generally 

 estimated by a measure of force derived originally 

 from comparison with the number of horses that 

 would be required to do the same work — the first 

 steam-engines having been used chiefly as substi- 

 tutes for horse labor. 



The other two sources of moving power are — 

 First, The attraction which exists between 

 bodies, and tends to make them approach each 

 other; and, Second, The Repulsive Power, 

 which exists, more or less, in all bodies, and tends 

 to drive their particles asunder. These influences 

 are universally diffused through bodies, and are 

 antagonists — i. e., opposed to each other in their 

 action. To the operation of these fundamental 

 properties of matter, all the phenomena of inani- 

 mate nature can be traced ; and animate beings, 

 though endowed with the independent principle of 

 life, are in no small degree subject to their control 

 while living, and when dead are solely obedient 

 to the laws of these great powers. 



They act with great energy, and both have 

 been used as sources of power in the steam- 

 engine. The first is applied in some kinds of 

 engines only (now called atmospheric engines) ; 

 the latter, either applied directly as a moving 

 power, or used to prepare for the action of the 

 attractive force, has been a leading element in 

 the operation of every sort of steam-engine; and 

 as steam is the medium through which the repul- 

 sive power is introduced, all are called steam- 

 engines, although the steam may not be the direct 

 cause of the motion. At first they were termed 

 fire-engines, the steam being formed by the action 

 of fire upon water. 



The attractive force was taken advantage of 

 by man, as a moving poAver — as in the water- 

 wheel, the windmill, the common pump — long 

 before the repulsive principle was applied, or even 

 thought of, as a source of motion. Now, Iioav- 

 ever, this great power, so long overlooked, has 

 almost entirely superseded the other ; acting in 

 the form of steam, it is seen everywhere, and is 

 the prime mover chiefly employed by civilised 

 nations of modern times. For ages a hidden 

 treasure, it has at last been brought to light; and 

 has placed Avithin the reach of mankind a force 

 so enormous, that it is limited only by the strength 

 of the materials Avhich must be employed to give 

 it effect; a power unremitting in its labors, and 

 universal in its application ; so versatile, that it 

 may be transferred from place to place, worked 

 at any time, and suspended or set in action again 

 at a moment's Avarning; — and Avithal so steady 

 and regular, so completely under our control, and 

 possessed of a self-regulating property to such an 



extraordinary extent, 'that it almost realises the 

 fable of Prometheus, and may fitly be compared 

 to an intelligent being devoted to our service. 

 The repulsive energy is the source of the power 

 of gunpowder as Avell as that of steam ; so that, 

 when we consider the great change effected by 

 the use of gunpoAvdcr in Avarfare, and the vast 

 and various influences of the steam-engine, this 

 remarkable principle may be said to have twice 

 reA r olutionised the Avorld. 



After a perusal of the above, Ave hardly need 

 carry our " Letter of Recommendation " any 

 further. 



Notes for Naturalists. 



One feature Avhich will mark 1851 Avith a 

 A\'hite stone in the calendar of Naturalists, Avas 

 the arrival of the first living Apteryx in this he- 

 misphere. The wing of the Apteryx Australis is 

 scarcely more than rudimentary, but has a strong 

 hooked claw at its extremity, and the feathers 

 of this species resemble, in their general cha- 

 racter, those of the cassoAvary. We paid a visit 

 to the stranger a few days ago, and found him 

 reposing Avith his head on his side — in other birds 

 it Avould have been under his Aving; but, Avith 

 becoming delicacy of feeling, he endeavored to 

 conceal his infirmity by giving the motion as if 

 he had a wing. Presently, he started, and stretch- 

 ed himself up almost to a fabulous height; then 

 sloAvly toppled forward, and gravely rested his 

 beak on the ground. This attitude is necessary 

 for the preservation of equilibrium, as the legs 

 arc placed quite behind the centre of gravity; 

 sturdy legs however they are , and formidable 

 the bloAvs the bird can inflict, not by kicking 

 behind, but by a foi'Avard stroke — the spur on 

 the heel cutting like a knife. The favorite lo- 

 calities of this bird are dense beds of fern ; and 

 when hard pressed by dogs (with Avhich he is 

 usually chased), it takes refuge in deep holes ex- 

 cavated by it in the ground. It is hunted by 

 torchlight, and is sought after Avith great avidity 

 by the natives, the skin being highly prized for 

 dresses worn by the native chiefs; the feathers 

 are also used to construct artificial flies for the 

 capture of fish, precisely after the European 

 fashion. Not the least of its peculiarities is the 

 position of its nostrils at the tip of the beak. In 

 seeking for the Avorms Avhich constitute its food, 

 the sense of smell takes the place of that of sight, 

 and the dexterity AvitliAvhich it seizes its active 

 prey, deep beneath the surface, is remarkable. 



Another species is known, Avhich has been call- 

 ed by Mr. Gould Apteryx Owenii, after Professor 

 Owen. Stuffed specimens are in the museums 

 at York, Ipswich, and the British Museum, also, 

 Ave believe. This species is very thickly clothed 

 Avith short feathers, transversely barred. A third 

 species has been described by Mr. Bartictt, which 

 he considers to be the true Apteryx Australis, 

 giving the name A. Mantelli to that figured by 

 Mr. Gould. 



Mr. Wallace has communicated to the Zoolo- 

 gical Society some interesting particulars relative 

 to that singular bird the "Umbrella Bird," inhabit- 

 ing the island of the Amazon, in South America. 



