*No. 245 Broadway, New-York City.* FOOTNOTES 1 —_Puddling_ is the kneading or rubbing of clay with water, a process by which it becomes almost impervious, retaining this property until thoroughly dried, when its close union is broken by the shrinking of its parts. Puddled clay remains impervious as long as it is saturated with water, and it does not entirely lose this quality until it has been pulverized in a dry state. A small proportion of clay is sufficient to injure the porousness of the soil by puddling.—A clay subsoil is puddled by being plowed over when too wet, and the injury is of considerable duration. Rain water collected in hollows of stiff land, by the simple movement given it by the wind, so puddles the surface that it holds the water while the adjacent soil is dry and porous. The term _puddling_ will often be used in this work, and the reader will understand, from this explanation, the meaning with which it is employed. 2 By leaving a space between the wall and the plastering, this moisture is prevented from being an annoyance, and if the inclosed space is not open from top to bottom, so as to allow a circulation of air, but little vapor will come in contact with the wall, and but an inconsiderable amount will be deposited. 3 The maps in this book are, for convenience, drawn to a scale of 160 feet to the inch. 4 The instrument from which this cut was taken, (as also Fig. 7) was made by Messrs. Blunt & Nichols, Water st., N. Y. 5 The slight deviations caused by carrying the drains around large stones, which are found in cutting the ditches, do not affect the general arrangement of the lines. 6 The low price at which this instrument is sold, $1.50, places it within the reach of all. 7 Except from quite near to the drain, it is not probable that the water in the soil runs laterally towards it. 8 Some of the drains in the Central Park have a fall of only 1 in 1,000, and they work perfectly; but they are large mains, laid with an amount of care, and with certain costly precautions, (including precisely graded wooden floors,) which could hardly be expected in private work. 9 The tile has been said, by great authorities, to be broken by contraction, under some idea that the clay envelops the tile and presses it when it contracts. That is nonsense. The contraction would liberate the tile. Drive a stake into wet clay; and when the clay is dry, observe whether it clasps the stake tighter or has released it, and you will no longer have any doubt whether expansion or contraction breaks the tile. Shrink is a better word than contract. 10 Taking the difference of friction into consideration, 1-1/4 inch pipes have fully twice the discharging capacity of 1-inch pipes.