CHAMBERS'S INFORMATION FOR THE PEOPLE. 



augmented to fourteen. Three of them are still 

 serviceable, and modern Rome is more copiously 

 supplied, perhaps, than any other city. 



The system of aqueducts was also introduced 

 into those countries that owed allegiance to the 

 mistress of the world ; in Greece, Italy, Spain, 

 and Gaul, many were erected. That at Nimes 

 was perhaps the oldest of these provincial aque- 

 v ducts ; it traversed a most diversified district, 

 piercing hills and crossing valleys. At the place 

 where it crosses the Garden, it is termed the 

 Pont du Gard ; it is 300 yards in length, and 

 is composed of three ranges of arches, one above 

 the other, to the height of 160 feet. 



Of the use of the aqueduct in recent times, three 

 instances are alone worthy of notice the Lisbon, 

 the Croton at New York, and the aqueduct from 

 Loch Katrine to Glasgow. The first of these, 

 completed in 1738, is about three leagues in 

 length ; near the city, it is carried over a deep 

 valley for a length of 2400 feet, by a number of 

 bold arches, the largest of which has a height of 

 250 feet, and a span of 115. The Croton Aque- 

 duct, which conveys the waters of the Croton 

 river for a distance of thirty-eight miles to the 

 city of New York, is one of the greatest under- 

 takings of modern times. It was commenced in 

 1837, and finished in 1842, and is calculated to 

 discharge upwards of 60 million gallons in twenty- 

 four hours ! The whole cost, including the 

 arrangements for distribution in the city, was 

 about twelve millions of dollars. As the magnifi- 

 cence of aqueducts depends upon the height and 

 number of arches requisite to carry them across 

 valleys, it may give some idea of that under con- 

 sideration, when it is stated that Haarlem River 

 is crossed by fifteen arches, seven of which are of 

 50 feet span, and eight of 80 feet, the greatest 

 height being 150 feet from the foundation to the 

 top of the mason-work. No essential change 

 occurs in the form of the channel-way from the 

 fountain reservoir on the Croton to the receiving 

 reservoir on the island of New York a distance 

 of thirty-eight miles except in crossing Haarlem 

 River, to reach the island, and in crossing a deep 

 valley on the island, where iron pipes are used. 



The Loch Katrine Aqueduct, which was finished 

 in 1859, is of the same nature from its com- 

 mencement at Loch Katrine to the Mugdock Re- 

 servoir, it is 25! miles long, 13 of which were 

 tunnelled, 3f miles are iron piping across valleys, 

 and the remaining 9 miles are open cutting and 

 bridges. Where the ground was cut open, the 

 surface was restored after the aqueduct was built. 

 The built and tunnelled part is capable of passing 

 50 millon gallons per day, and the pipes across 

 the valleys, which are four feet diameter, deliver 

 about 24 millions. The total cost of the aqueduct 

 was .468,000, or an average of .18,000 per mile. 

 The Ganges Canal is another very important piece 

 of hydraulic engineering, in the course of which 

 there are several very large and extensive bridges 

 and aqueducts. 



Compared with the hydraulic works of the 

 Romans, it must be confessed that the efforts 

 made to supply modern cities, in Europe at least, 

 are insignificant enough. Some years ago, a 

 covered conduit, 80 miles long, was constructed, 

 which conveys 8 million gallons of pure chalk 

 spring-water from the sources of the Dhuis, in 

 Champagne, to Paris ; and more recently, the 



498 



chalk springs of the Vanne, calculated to yield 22 

 million gallons a day, have also been brought to 

 Paris, a distance of 104 miles. 



In 1867, a Royal Commission was appointed 

 for the purpose of inquiring into the condition of 

 the water-supply of London ; and numerous differ- 

 ent schemes were laid before them. The first on 

 the list was that of Mr Bateman, who proposed to 

 utilise the high drainage-grounds of North Wales, 

 which supply the head-waters of the river Severn, 

 the drainage area of which is 204 square miles. 

 The water was to be conveyed in an aqueduct, 

 and discharged into large reservoirs, proposed to 

 be constructed about ten miles north-west of 

 London. The total distance would be a little over 

 1 80 miles, and the aqueduct was intended to be 

 able to carry 230 million gallons per day. The 

 total cost of the scheme, which was to be brought 

 in in four different instalments, was estimated at 

 ;i 1,400,023. The committee reported against the 

 scheme, on account of the objections of its great 

 distance, which would be certain to prove a fatal 

 one, as the whole metropolis would be reduced to 

 complete want in the event of accident occurring 

 to the aqueduct, more especially during the hostile 

 occupation of the country in case of war. 



The next scheme considered was that proposed 

 by Messrs Hemans and Hassard, who proposed 

 to supply the metropolis with water from the lakes 

 of Cumberland and Westmoreland. The distance 

 from London is 240 miles, area of district 230 

 square miles, and the available quantity of water 

 287 million gallons per day, and the estimated 

 cost ^13,500,000. The remarks of the Com- 

 missioners on this scheme were to the same effect 

 as in the case of Mr Bateman's ; and they con- 

 cluded by remarking, that they held it to be 

 erroneous in principle that any one town or 

 district should take possession of a gathering- 

 ground geographically belonging to another, unless 

 it can be clearly shewn that circumstances render 

 such a step justifiable. The Commissioners came 

 to the conclusion, that the Thames water has many 

 good qualities, which render it peculiarly suitable 

 for the supply of the metropolis, and which give 

 it in some respects a superiority over the soft 

 waters usually obtained from high gathering- 

 grounds. It is well aerated, has good keeping 

 qualities, and is perfectly safe as regards action 

 on lead and iron. 



In 1869, and again in 1871, a bill was before 

 parliament to bring the water of St Mary's Loch 

 into Edinburgh, a distance of forty miles. But 

 a strong opposition having arisen, on a variety of 

 grounds, among the inhabitants of Edinburgh, it 

 was thrown out by the committee of the House of 

 Lords. 



SOURCES OF WATER. 



The primary source of all fresh water is rain 

 (see METEOROLOGY). Rain-water, as it is formed 

 in the upper regions of the atmosphere, is the 

 purest that nature supplies ; but in its descent, it 

 carries down with it whatever impurities it comes 

 in contact with, which, in the neighbourhood of 

 towns, are numerous, consisting of various gases, 

 together with soot and other floating particles, 

 organic and inorganic. Rain-water has a strong 

 affinity for organic impurities that is, the corrupt- 

 ing ingredients derived from vegetable and animal 



