i6o 



NATURE 



\yune 15, 1876 



If the object is merely to raise water this can be done without 

 the employment of either water-wheel or turbine. Wlien a small 

 quantity is required to be raised to a considerable height the 

 Montgolfier ram is employed. No. 1,996, which I have before 

 me, is a glass model of such a ram, but I fear it is too small to 

 be visible, except to those who are very near to the table. You 

 are, however, all aware that the principle of action consists in 

 the sudden arrestment of a column of water flowing with a velo- 

 city due to the head. The water on being arrested performs 

 two functions, a small portion raises an outlet valve, and thereby 

 passes into an air-vessel against a pressure competent to drive 

 the water up to the desired height ; while the main body recoils 

 along the supply pipe ; then, the escape valve having opened the 

 water that has recoiled, returns, a large portion passes out of the 

 valve, and thus the velocity being fully established the escape 

 valve shuts and causes another arrestation and a repetition of the 

 working. This is an implement by which a large volume of 

 water coupled with a low fall, can be made to raise a portion of 

 itself to a great height. But there is a converse use of water, 

 wherein the employment of a small stream of water moving 

 rapidly (owing to its having fallen from a considerable height) is 

 caused to induce a current in other water and to draw it along 

 with itself at a diminished velocity but still with a velocity com- 

 petent to raise the united stream to a less height, and in this 

 manner many swamps and marshy lands have been drained. 



This employment of the induced current as a prime mover is 

 described by Venturicr in the record of his experiments made at 

 the latter end of the eighteenth century, and within the last few 

 years Mr. James Thomson has applied the same principle with 

 great success in his jet pump. 



The next mode I shall notice of obtaining motive power from 

 water, is also one where it operates by an induced current ; this 

 is the " Trombe d'eau," an apparatus wherein water falling 

 down a vertical pipe, induces a current of air to descend with it. 

 The lower end of the vertical pipe being connected with the upper 

 side of an inverted vessel, the bottom of the sides of which 

 vessel is sealed by a water joint, then the water dashing upon a 

 block placed below the mouth of the pipe, is separated from the 

 air, so that while the water descends and escapes from under the 

 sides of the vessel, the air rises and accumulates in the upper 

 part from whence it can be led away to blow a forge fire. These 

 machines are described in Belidor's work. 



The utilisation of the rise and fall of the tide is also fully 

 described byBelidor, who gives drawings of channels so arranged 

 that during both the rise and fall of the tide the wheel, notwith- 

 standing the reversal of the currents, revolves in one and the 

 same direction. The tide is a source of power which it is highly 

 desirable should be utilised to a greater extent than it is ; if we 

 consider the enormous energy daily ebbing and flowing round 

 our shores, it does seem to be a matter of great regret that this 

 energy should be wasted, and that coal should be burnt as a 

 substitute. 



The last mode in which power may be obtained from water, 

 to which I have to allude, is that of the employment of the 

 waves. 



Earl Dundonald, better known as Lord Cochrane, proposed 

 by his patent of 1833 to utilise this power for propelling a vessel; 

 this he hoped to accomplish by the use of cylinders containing 

 mercury, the oscillations of which were to cause a vacuous con- 

 dition in the cylinders, and thereby give motion to an air- 

 pressure engine. Lately we have had produced before the 

 Institution of Naval Architects, and also before the British 

 Association at Bristol, the apparatus of Mr. Tower, by which 

 the motion of the waves is to be utilised ; a model constructed 

 on this principle has driven, it is said, a boat against the wind at 

 some two or three miles an hour. 



The next kind of prime-movers in order of date to be con- 

 sidered, are those that are worked by the wind. 



Although undoubtedly the propelling of a ship by sail.^, and 

 even the winnowing of grain, must have long preceded the 

 invention of a prime mover driven by water, yet the employment 

 of the wind as a source of motive power for driving machinery, 

 appears to be but of comparatively recent date. It is said that 

 the knowledge of this kind of prime mover was communicated 

 to Europe by the Crusaders on their return from the East, but 

 it is difficult to see what foundation there is for this statement. 

 It appears to be certain, however, that wind -motors were com- 

 monly employed in France, Germany, and Holland in the thir- 

 teenth century. 



We can easily understand that in countries where water falls 

 in quantities and rapid streams are abundant, the windmill would 



not, owing to its uncertainty, be resorted to ; on the other hand, 

 in inland countries and in countries like Holland, where the 

 streams are sluggish, and where there is a large amount of land 

 to be drained, the wind, although still uncertain, would never- 

 theless be a valuable power, and therefore would be utilised. 



Prime movers to be worked by the wind appenr to have been 

 made practically in only two forms, viz , the common ore, 

 wherein a nearly horizontal axle carries four or more twisted 

 radial sails, and that one wherein the axle is vertical and the 

 arms project from it laterally either as radial fixed arm's, as 

 curved fixed arms, or as arms having a feathering motion similar 

 to that of paddle-wheels. Where the arms are straight and fixed, 

 some contrivance must be resorted to to obtain a greater pres- 

 sure of wind on one side than on the other. 



Bessoni, in his work " The Theatre of Instruments and Ma- 

 chines," published at Lyons in 1582, describes a windmill with 

 vertical spindle and curved horizontal arms, placed in a tower 

 with a wind-guard, and by the drawing shows it working a chain- 

 pump. Belidor also says in Article 852 that windmills with 

 vertical axles were well known ii Portugal and in Poland, and he 

 describes how that they work within a tower the upper part of 

 which was fitted with a movable portion to act as a screen to 

 one side of the mill. 



I will not detain you by an allusion to the sailing chariot men- 

 tioned by my Uncle Toby in "Tristram Shandy," nor will I 

 pause to describe the very modem one, that is to say, not more than 

 about thirty years old, which was employed upon Heme Bay 

 Pier. In fact this Exhibition gives but little encouragement to 

 pursue the subject of prime-movers worked by wind, as I have 

 not as yet come across in the Catalogue any apparatus illus- 

 trative of the subject. 



It is to be regretted that the use of this kind of prime mover, 

 the windmill, is on the decline. It is a power that costs nothing ; 

 the machinery can be erected in almost any situation ; and 

 although such a motor cannot by itself be depended on, being 

 of necessity " as uncertain as the wind," it nevertheless might 

 be commonly employed as an auxiliary to steam-power, dimi- 

 nishing the load upon the engine in exact proportion as it was 

 urged by any wind which might happen to blow. 



1 may say, to the credit of our American brethren, that they 

 employ on their sailing-ships a windmill known by ihe sailors 

 as " The Sailor's Friend," to pump, to work windlasses, and to 

 do all those matters which in a steam-ship fall to the lot of the 

 donkey-engine and steam winch, unless, as in a recent voyage ii 

 which all Englishmen have been so much interested, these duties 

 were imposed upon the baby elephant. 



There is one motor which may be put either into this class or 

 into the next, where we consider the application of heat ; I 

 allude to the smoke-jack, but beyond recognising its existence 

 as a prime mover, and a very early one indeed (it is to be found in 

 Zoncas' work published in 1 621), attention need not be bestowed 

 upon it. 



We now come to consider those prime movers which are 

 worked by the immediate, and not by the secondary, action, of 

 heat. 



The direct rays of the sun have, for a very long time pist, 

 been suggested as a means of obtaining motive power. Solomon 

 de Cans in his work, published in 1615, describes a fountain 

 which is caused to operate by the heat of the sun's rays expand- 

 ing the air in a box and expelling thereby, through a delivery 

 valve, the water from the lower part of the box. When the 

 sun's rays have been withdrawn, the air, cooling, contracts a 

 suction valve, opens and admits more water into the box to be 

 again displaced on the following day. He also gives a drawing 

 of an apparatus where the effect of the sun's rays is to be intensi- 

 fied by a number of lenses in a frame. Solomon de Cans pro- 

 poses these machines as mere toys to work an ornamental 

 fountain, but Belidor, by Article 827, describes and shows 

 a sun pump consisting of a large metallic sphere, fitted 

 with a suction pipe and valve, and a delivery pipe and 

 valve and occupied partly by water and partly by air, the 

 suggestion being as in the case of Solomon de Caus, that the 

 heat of the sun in the daytime expanding the air should drive up 

 the water into a reservoir, while the contraction of the air in the 

 night-time should elevate the water by the suction pipe and re- 

 charge the sphere for the next day's work. In modern times, as 

 we know, some attempts to obtain practical motive power from 

 the direct action of the sun have been made, and notably by 

 Capt. Ericsson. 



The temptation to endeavour to bring into practical use a 

 machine of this character is very great. We were told by our 



