In another part of the same field, we had a spring of excellent water, where, "from the time whereof the memory of man runneth not to the contrary," people had fancied they found better water to drink, than anywhere else. It is near a ravine, through which a main drain is located, and which is now graded up into convenient plow land. To preserve this spring for use in the Summer time, we procured a tin-worker to make a well, of galvanized iron, five feet long and ten inches diameter, into which are conducted the drain and the spring. A friendly hand has sketched it for us very accurately; thus: [Illustration: Figs. 45 & 46.--HOW TO PRESERVE A SPRING IN A DRAINED FIELD.] The spring is brought in at _a_ by a few tiles laid into the bank where the water naturally bursts out. The pipe _b_ brings in the drain, which always flows largely, and the pipe _c_ carries away the water. The small dipper, marked _d_, hangs inside the well, and is used by every man, woman, and boy, who passes that way. The spring enters six inches above the drain, for convenience in catching its water to drink. By careful observation the present Winter of 1858-9, the impression that there is some peculiar quality in this water is confirmed, for it is ascertained that it is six degrees warmer in cold weather than any other water upon the farm. The spring preserves a temperature of about 47 deg., while the drain running through the same well, and the other drains in the field, and the well at the house, vary from 39 deg. to 42 deg.. We confess to the weakness of taking great satisfaction in sipping this water, cool in Summer and warm in Winter, and in watching the mingled streams of spring and drainage water, and listening as we pass by, to their tinkling sound, which, like the faithful watchman of the night, proclaims that "all is well." POSITION AND SIZE OF THE MAINS. Having fixed on the proper position of the outlet, for the whole, or any portion of our work, the next consideration is the location of the drains that shall discharge at that point. It is convenient to speak of the different drains as _mains_, _sub-mains_, and _minors_. By _mains_, are understood the principal drains, of whatever material, the office of which is, to receive and carry away water collected by other drains from the soil. By _minors_, are intended the small drains which receive the surplus water directly from the soil. By _sub-mains_, are meant such intermediate drains as are frequently in large fields, interposed across the line of the minors, to receive their discharge, and conduct their water to the mains. They are principally used, where there is a greater length of small drains in one direction than it is thought expedient to use; or where, from the unequal surface, it is necessary to lay out subordinate systems of drains, to reach particular localities.