one cubic foot per second will irrigate 220 acres; and in others that one cubic foot per second will irrigate 70 acres of early kharif, 50 acres of rice, and 120 acres of rabi. Major Home, R.E., found by actual measurement that, with the tank or reservoir irrigation, as practised in Ajmere, the average quantity of water required for one acre was 177,260 cubic feet, or in other words, one cubic foot per second irrigated 178 acres. Mr. E. C. Palmer also, by actual measurement, found that in the case of irrigation from the Bari Doab Canal, the quantity of water required for the irrigation of an acre of wheat was 42,500 cubic feet, and from his experiments on the quantity of water required to flood the ground as is done in rice cultivation, he concluded that 326,700 c. f. of water would be required for the irrigation of one acre of rice. If we take the irrigating season for wheat as four months, and the same for rice, these figures will give 247 acres of wheat and 32 acres of rice, as the irrigating duty of one cubic foot per second. These figures take no account of the rainfall--that is the quantities of water stated as necessary are those which would be required in the total absence of rain.

It is very difficult for any one not acquainted with India to realize the magnificent services which the canals have rendered in emergencies. In 1868-69, when both the monsoon and the cold season rains almost entirely failed in the North-west Provinces, when the local Government was practically panic-stricken, and when it was generally feared that nothing could prevent enormous loss of life from famine, the Ganges Canal afforded a grand example of what it could do under able management. In that one year the irrigated land increased from 534,000 acres to 1,078,000 acres, and the duty per cubic foot per second rose from 152 acres to 232 acres. So serious was the state of affairs deemed to be that an order was issued, giving authority to the canal officers to sacrifice and pay compensation for crops of sugar-cane and indigo, rather than allow any irrigable grain crops to be lost. On the whole, the services done by the Ganges Canal in that year were such as any nation might be proud of. Had the Ganges Canal been in America, or perhaps even in Victoria, the world would have heard much more than it has about the management displayed. Colonel Brownlow, who was then superintending engineer of that canal, prepared a most valuable and instructive report regarding the canal administration during that year. Considering the extent and value, as well as the nature and success of the services performed by Colonel Brownlow and his staff, it would be difficult to imagine a document more un-American in its character than the report he prepared.

A paper such as this would be incomplete without some remarks regarding the introduction of irrigation into New South Wales and the adjoining Colonies. In the correspondence on the subject which

recently appeared in the Sydney Morning Herald, none of the writers seemed to be aware that the consideration of the irrigation question in New South Wales was warmly advocated many years ago by Mr. Bennett, Engineer-in-Chief for Roads and Bridges; and that Mr. Moriarty, Engineer-in-Chief for Harbours and Rivers, also many years ago not only advocated the consideration of the question, but took most important action in the matter. The result of that action is, that at the present time the elaborate surveys, cross sections, and statements of discharges of the Murray, the Murrumbidgee, and the Darling, which Mr. Moriarty had then prepared contain the most valuable information in existence regarding the possibility of carrying out irrigation works on an extensive scale with those rivers as the sources of supply.

The inquiry into the prospects of irrigation in Victoria has been dealt with exhaustively by Mr. George Gordon. Some months ago that gentleman also prepared a valuable report on proposed improvements in the Darling, and when doing so had the benefit of the survey maps of that river which had been made under Mr. Moriarty's direction, and which were on this occasion specially lent under official sanction. As the public does not seem to be wellinformed as to what is being done in the matter of irrigation, it may be mentioned that at the present time Mr. Bennett, as Engineer-in-Chief for sewerage works, is preparing land and having works carried out for sewage irrigation.

In connection with the introduction of irrigation into New South Wales, the question of evaporation has received much attention, but it has been dealt with so ably and fully by Mr. Russell, Government Astronomer, that only a passing notice is required. It has already been stated that the loss by evaporation from the Ganges Canal and its branches and distributaries amounts to ten minutes' supply in twenty-four hours on an average. The maximum evaporation registered at Roorkee, with a hot wind blowing continuously, was half an inch in twenty-four hours. From a series of experiments made in Southern India on a reservoir 1,375 acres in extent, Major Mayne, R.E., concluded that the mean evaporation at that place was at the rate of 0.165 of an inch in twenty-four hours, that is, 60 inches per annum.

It has been stated in the recent controversy that irrigation is likely to cover the ground with a deposit of salt, and that this has taken place on a large scale in India. There are extensive tracts of country in the North-west Provinces in which crops grow badly or not at all, and which are more or less covered with a saline efflorescence. The subject of dealing with this "oosur," as the salt is locally termed, occupied much attention some years ago. I was in India at that time, and read all the information I could obtain on the subject, and I do not recollect that a single authority endeavoured to show that the efflorescence was due to deposi

As a matter of fact,

the oosur plains were in So far as I am aware,

from canal water. existence before canals were thought of. the only foundation for the idea that oosur is due to canal irrigation is that in the first place canal water passing through oosur land to good land will gradually spread the oosur over the latter, and that in the second place excessive irrigation of land slightly impregnated with oosur will bring the salt to the surface.

Irrigation is paid for in India according to the nature and acreage of the crops irrigated, not because this is the best system, but because it is believed to be better suited to the country than any other yet proposed. In Australia, I think, it would be better to follow the European system of paying for the quantity of water used. As the water supply in Australia is very limited, no pains should be spared to raise the duty per cubic foot per second to the highest figure obtainable.

Another point which I wish to refer to is the comparatively small quantity of water discharged by the Australian rivers, and the consequent impossibility of obtaining large supplies for irrigation from them. When the Ganges Canal was constructed, the whole available cold season supply was taken from the river; yet at the distance of only a few miles the discharge in the river was found to be very considerable, and further on it increased to such an extent that the supply taken from the canal was found to be little missed. From what I have read and seen of the rivers of this Colony I think it is highly probable that the effect of withdrawing a large supply from some of them would be of less importance comparatively than in the case of the Ganges.

In India irrigation works have ensured large tracts of country against the possibility of famine, and they have brought under permanent cultivation hundreds of thousands of acres, from which few or no crops were formerly obtained. Although irrigation cannot be conducted on such a scale in this Colony, still the field is a wide one. So far as irrigation is concerned, the Chinaman appears to be the only cultivator who has discovered that "Providence helps those who help themselves." In a country where labour is so expensive as it is here, exceptionally favourable circumstances are required to render irrigation profitable; still it seems scarcely credible that such favourable instances have not arisen. The time for extensive irrigation works in this Colony is surely, if slowly, approaching; but before its arrival, if private enterprise fails to carry out works of the same kind on a small scale, I believe it will be from want of enterprise and knowledge, and not from want of opportunity.

Tanks and Wells of New South Wales, Water Supply and Irrigation.

By A. PEPYS WOOD, Assistant Engineer, Roads and Bridges Department.

(Communicated by W. H. WARREN, C.E.)

[Read before the Royal Society of N.S. W., 7 November, 1883.]

THE necessity for a liberal consideration of the question of water supply for the dry districts is of such rapidly increasing importance to those districts and to the Colony generally, that the time has arrived for active steps to be taken to obtain, by actual survey and observation, the data necessary to determine the best means to be adopted to conserve and distribute, in an economical and effective manner, that portion of our rainfall now carried off by our river systems and discharged into the ocean, conferring but little benefit on its course; though running through districts where the soil only requires its invigorating agency to produce in abundance any vegetable growth suited to the climate.

In framing this paper I have divided the subjects to be dealt with into two sections :

L-Water supply for stock routes.
II.-Water supply for irrigation.

This course is advisable for two reasons: because the works to be dealt with, that have up to the present time been carried out by the Government, have been solely for the improvement of the stock routes; and because the important works necessary on these routes cannot generally be brought within the scope of any scheme having irrigation as its main object. Isolated cases may occur where watering-places could be provided for in this way, but as a rule it will be found that the supply for this purpose must be obtained from works complete in themselves, and constructed solely with a view to meet the requirements of stock traffic. This is a necessary consequence, inasmuch as stock routes are laid out to afford the best and shortest practicable connection between the terminal points, and without any reference to those differences of level that would prevent their being introduced into a general scheme of water supply. Cases might occur where points on such routes could be supplied from the irrigation channels, but such points might not be suited to the general division of the watering stages along that route.

I. WATER SUPPLY FOR STOCK ROUTES.

The stock routes of the Colony have an important bearing on pastoral industry, and deserve greater attention and expenditure in opening and improving them than they have hitherto received. Much may have been done, but very much more remains to be done before they can be considered efficient in facilitating the transmission of stock. They are the only avenues from the pastoral districts to the consumer, and from one pastoral district to another. Properly watered and managed they would be invaluable as affording a certain outlet to the markets, and also as a means of reducing to some extent the enormous losses that so often overtake the sheep-farmer during dry seasons; for at such times he would have the chance of removing some portion of his stock to more favoured localities for water and feed. It has unfortunately been the case that, even when improved, these routes have not been of as much service as is desirable. This is to be attributed to the long intervals separating many of the works that have been constructed for watering purposes; to the defective maintenance of many of those works; and to the defective conditions regulating grazing on the stock routes. When it has been determined to water any stock route, arrangements should be made to construct all the works necessary to complete the chain of communication, instead of constructing wateringplaces that, until that chain is complete, can only be rendered available at considerable loss and injury to travelling stock, or when the long intervals separating them are bridged by natural supply, at which time there is but little need for the water that has been artificially conserved. It is unfortunately often the case that many of these routes are practically closed, by want of feed, even when plenty of water is obtainable; and it is a matter of great importance that this evil should be remedied as far as is practically possible, and measures adopted to make the stock routes of sufficient width, to withdraw them from lease, and protect them from being grazed on by other than travelling stock.

In the year 1869, the Government first practically recognized the necessity for constructing watering stations on the stock roads, and a sum of £5,000 was then voted by Parliament for works on the Booligal and Wilcannia Road, and handed over to the Roads Department for expenditure. At that time no works of a similar nature had been carried out by the Government; and this, combined with an imperfect knowledge of the character of the country to be dealt with, led to a course of action being adopted which, however suitable it might have proved under different circumstances, required considerable modification to adapt it to the existing conditions of the question. The primary object was to obtain water by sinking, and with this view a boring plant,