indirect benefit, as indicated by the difference of rent between irrigated and unirrigated land, has been most marked. At a very moderate estimate, the increased returns from the land throughout the Milanese alone may be estimated at £270,000, and in the other irrigated provinces at about £290,000 per annum ; representing a capital value of fully fourteen millions sterling due to the employment of water in the agriculture of this fertile region. This statement is, however, so to speak, but one side of the account; it shows us what has been realised, but it does not show us what has been spent. The remote epochs at which the great canals, and a very large proportion of the branches, were constructed the admixture of works for navigation with those required purely for irrigation—and the difficulty of obtaining access to the records of private undertakings, oppose almost insuperable obstacles to the formation of a trustworthy estimate of the amount of capital which has been expended in producing throughout Lombardy that astonishing system which we have been describing. It is not merely the cost of canal works which forms the chief item in the expenditure; in addition to this, vast sums have been expended in adapting the ground for the use of water-high places have been lowered-low places have been raised—the entire surface of the country has been plastic, as it were, in the hands of the irrigators-and the amount of capital thus invested in the soil has been very great. Signor Cattaneo ("Instituzioni Agrarie dell' Alta Italia," &c., p. 44-51) estimates the cost of introducing, over an area of 500,000 acres, a system of irrigation on a grand scale like that of the Milanese, with its great trunk-lines of canal, its first-class branches, its modifications of surface, its immense establishments for farming purposes, and its internal works for the distribution and application of the

water, at forty millions sterling, or £80 per acre! From an analysis of the items of this estimate, I think it is in excess of the truth; but making every possible deduction, even to the extent of one-half, it would still appear that, for the irrigation of the million acres, which, in round numbers, represents the total irrigated area of Lombardy, there must have been expended a capital of not less than the sum above stated. This expenditure has been spread over seven hundred years; it has converted a maremma into a garden; and though, when presented in the form of a bare money account, its results are not great, yet its real effects are to be traced, and its true history read, on the face of the land, and in the material condition of its two and a half millions of inhabitants.

The river system of Lombardy is drawn upon for irrigation to the following extent :

Cubic feet per second.

Serio,
Oglio,

Mella,

Clisio,

Mincio,

Minor Streams,
Springs,

Total,

2,260

4,047

298

501

2,895

429

828

720

600

2,540

15,118

I have before mentioned that the total average discharge of the various rivers is nearly 30,000 cubic feet per second, so that one-half of this is utilised by being made available for the three objects of irrigation in Agriculture, navigation in Commerce, and supplying motive force in Industry. The general average area irrigated by each cubic foot of water, throughout Lombardy, amounts to 70.2 acres, and the general rate of cost per acre for water only is very nearly 3s. 6d.

Throughout the entire valley of the Po, including Piedmont and Lombardy, the extent of irrigation amounts to 1,547,905; or, in round numbers, 1,600,000 acres, being about one-sixth of its total area. The mass of water utilised is nearly 24,000 cubic feet per second, the value of which, in capital, at £250 per cubic foot per second amounts to four millions sterling, and the increased rental due to its employment is, at a very moderate estimate, £830,000 per annum. I need not dwell longer on such details. A few of them, even though they are only approximate, are still interesting, as giving some distinct ideas of the extent and the value of the system. To minds accustomed to the statistics of England, they may not seem imposing; but regarded in reference to the comparatively limited districts to which they apply, they are, in truth, large and important.

I have now completed the first great section of my work, in giving the historical and descriptive details of the canals of irrigation in Piedmont and Lombardy. The second-which will include the systems of Measurement, Distribution, and Practical Application of the waters, with the Legislation of Irrigation within the same kingdoms— remains to be completed; and to these branches of the subject I propose to devote the succeeding portion of this

work.

APPENDICES.

APPENDIX A.

LIST OF ITALIAN AUTHORS ON THE HISTORY, PRACTICE, AND LEGISLATION OF IRRIGATION IN NORTHERN ITALY.*

[Referred to at p. 15, Chapter 1, Part I.]

SECTION I. ON THE CONSTRUCTION AND ARRANGEMENT OF WORKS FOR OBTAINING THE SUPPLIES OF CANALS AS HEADS, ESCAPES, WEIRS, &c. &c.

1. BACIALLI, GIOVANNI-* Opuscolo sulle Pescaje (Temporary Dams). 2. LECCHI, ANTONIO-* Trattato dei Canali Navigabili.

3. FERRARI, FRANCESCO BERNARDINO-* Dissertazione sopra la costruzione delle Chiuse (Dams) per la derivazione dei Canali Regolati.

4. MASETTI, GIOVAN BATTISTA-* Notizie istoriche intorno all' origine ed alla formazione del Canale Naviglio di Bologna.

5. BRUSCHETTI, GIUSEPPE * Storia dei progetti e delle opere per la Navigazione interna del Milanese.

6. PAREA, CARLO * Sulla Navigazione interna del Milanese.

7. FOCACCI, FRANCESCO-* Metodo per correggere le altezze eccessive delle pescaje e per migliorare gl' Idraulici Edifizi per mezzo principalmente di Cateratte oscillanti.

8. POLENI, GIOVANNI-* Delle Pescaje, o cateratte di lati convergenti, per le quali si derivano le acque dei fiumi.

N.B.-Copies of each of the works marked by an asterisk have been procured for deposit in the Library of the College of Civil Engineers at Roorkhi, on the Grand Ganges Canal.

* The original list, as given to me by Baron Plana, bears the following title: "Elenco di opere sulle Pratiche Techniche degl' Ingegneri Italiani e sulle Discipline Legali nel derivare, condurre ed applicare le acque agli usi industriali ed agricoli."