1829.] 
Scientific Intelligence. 
345 
the contrivance of a series of self-acting sluices adapted to every site and to every 
state of weather, all the invention of the engineer, who had the honor of first submit- 
ting the plan to the public. The success of the method at Rothsay in the Isle of Bute, 
where it originated, induced a company of patriotic gentlemen in Greenock to lend 
themselves to the undertaking ; and their works, now nearly finished, form one of 
the greatest wonders of art in the country. The rains collected from a number of 
barren hills in the neighbourhood of Greenock, arc collected into a large natural re- 
servoir at their base, and conveyed along the face of mountains, carried across deep 
ravines, and conducted along the edges of rocky precipices in a gently sloping aque- 
duct, about six miles long, to the brow of a hill surmounting the town; thence the wa- 
ter is led along in small aqueducts or lades to the mills, (which are situated on the 
face of the hill,) amounting to thirty-three in number, and (from their various 
heights, being placed successively below each other, ) yielding a power arising from 
the extent of their falls, equal to that of 2000 horses, (as appears by the report of the 
Company’s engineer,) and if certain improvements be afterwards made as indicated, 
they may be made to yield a power equal to that of 3000 horses, a mechanical power 
far exceeding that of the great manufacturing town of Glasgow, and its populous 
vicinity. The water collected into the great natural reservoir with some small 
auxiliaries, is drained from about 481)0 acres of ground, it covers about 300 acres, in 
which the water stands, about forty-six feet deep, and it is capable of containing about 
300 millions of cubic feet of water, or of discharging 600 millions of cubic feet annu- 
ally; so that besides supplying the town of Greenock amply with water for culinary 
purposes to the amount of 50 millions of cubic feet annually, the reservoir can 
furnish 2464 cubic feet of water per minute, for 310 days (the working days) in the 
year, for the period of twelve hours a day. The most astonishing circumstance 
regarding this immense public undertaking is, that they can afford to give their 
Water so cheap to the people who take their mills, . that the price of a horse’s power 
is reduced to about the twentieth part of what it would cost, were it derived from 
steam. The expense of steam engines and fuel, would by the general adoption of 
this plan throughout the country he entirely done away with ; coals and many 
other articles of consumption, would be rendered cheaper ; the smoke of public- 
works would be abolished in a more effectual way than by bprning ; and the health 
and morals of the lower classes, the last, but not the least important of the advan- 
tages to be derived from it, would be improved by the removal of manufactories 
from confined situations in crowded towns to airy and salubrious situations in the 
country .— New Monthly Mag. No. 101. 
3. Mr. Motley's Arch Suspension Bridge. 
The admirers of mechanical ingenuity, and those who take an interest in the ar- 
chitectural improvements of the metropolis, will, we are sure, feel gratified by a visit 
to Mr. Motley’s model of a wrought iron arch suspension bridge, now exhibiting at 
the Strand. The principle of Mr. Motley’s improvement, for it is not, as lie allcdges, 
his invention (as the celebrated Scbafflmusen bridge in itself proves), is to do away 
with lateral pressure, thence of the necessity of abutments by removing the pres- 
sure or weight of the bridge from, as at present, the top to the bottom of the struc- 
ture and resting it on a simple trussed beam or tension line. This tension line, 
which is ensured by a very ingenious apparatus of inflexibly jointed iron vertical 
bars and horizontal lines, (the arch being the reverse of our inverted one of our abut- 
ment bridges,) constitutes the carriage way of the proposed suspension bridge over 
the Thames, from Charing Cross through Scotland Yard to near King’s Arm’s Stairs. 
Corresponding with this tension line and parallel to it, is another on the top of the 
arch which may he used as a floor for an arcade of shops, or as a foot way, accord- 
ing to the height or number of the arches. The advantages of such an arrangement 
are obvious. Its practicability has been borne testimony to by the highest scien- 
tific and practical authorities, amongst others by professor Lardncr, Dr. Birkbeck, 
and Mr. Tredgold ; and indeed is made evident by an inspection of the model itself. 
4. Anti-convulsion System of Geology. 
In a notice of a work entitled ‘ Lettres sur tes Revolutions (he Globe,' in the section 
of the Natural Sciences of the ‘ Bulletin Universe!, ' the Baron de Ferussac repeats an 
opinion maintained by him on former occasions in the same Bulletin, that the pre- 
sent state of the Earth's surface in a geological point of view, is the last, or rather 
the most recent, of a series of successive and gradual modifications ; that, in fact, 
there have not been any revolutions, properly so called, on the globe ; but an unin- 
terrupted succession of phenomena diminishing in importance with the course of 
