44 On the making of Watering Ponds. 



rent prices of lime, or the distance it may be necessary to convey it, 

 as well as the clay, or the other materials for the work. A pond of 

 sixty feet diameter, by six feet deep, will contain upwards of^QO hogs- 

 heads of water ; one of forty-five feet, by five feet, near 400 hogs- 

 heads a vast supply, when obtained at so small an expense. 



Experience now of many years, and the universal use of these ponds 

 in this district, wherever wanted, have now proved them, when care- 

 fully made, so effectually to retain water, to preserve it of so good a 

 quality, when not fouled by the treading of cattle, and to be appli- 

 cable to so many situations, that they cannot be too strongly recom- 

 mended in all high situations, where water may be much wanted, or 

 in all other situations, where the water may be of bad quality. They 

 are equally applicable to dry wolds, downs and heaths, which are 

 without water, as to every fenny tract which has too much of it, but 

 of a brackish or unwholesome quality. North Riding Report, p. 24:3. 



No. XII. 



ON WARPING IN ITALY. 



FROM some late accounts, which have been published of the agri- 

 culture, and statistics of Italy, it appears, that a species of warping 

 has been long known in Tuscany. It is there called colmata. The 

 rivers in that country carry down with them vast quantities of mud 

 and sand, by which their discharge into the sea is impeded, and great 

 marshes are formed, not only at the mouths of these rivers, but in 

 their courses, when they are passing from one level to another. Tor- 

 ricelli, it is said, was the first who taught his countrymen to inclose 

 the marsh with a dike or embankment ; to admit into this inclo- 

 sure the water of the rivers ; to force this water, by means of sluices, 

 to remain stagnant as in a lake, so as to deposit its mud ; and by the 

 sediment so produced, to raise the level of the bottom. At one time, 

 three or four inches of earth have been often deposited ; the opera- 

 tion has been several times repeated in the course of a year ; and the 

 level so much raised, that the ground is no longer liable to be over- 

 flowed by the river. The soil thus acquired is of the highest ferti- 

 lity ; and an instance is mentioned, of a piece of ground thus treated, 

 which yielded 25 measures of wheat from one *. Necessity was the 

 parent of this operation in Italy ; whereas, on the banks of the Hum- 

 ber, it seems to have originated from accident, and has been carried 

 on, by a zeal for improvement, and the prospect of gain. 



* Edinburgh Review, for March 1817, p. 44, 45. Torricelli, the celebrated 

 inventor of the barometer, was born anno 1608, and died anno 1647. 



