nection with tile-making is, in
many districts, to procure clay sufficiently free from lime. Tiles
are very often sold by sample, sent a considerable distance, and it
becomes necessary to test them, which we do (for
lime) by placing them in water for a night; and, if lime is present
in the tile, it will, of course, swell out, and break the latter,
or leave it in a riddled state.

I have now endeavored to answer the queries in your postscript, and
I have carefully avoided enlarging on some points in them with
which your readers are already familiar. If I shall have thrown a
single ray of additional light on this subject across the Atlantic,
I shall be amply repaid for any attention I have given to
thorough-drainage during the past twelve years.

I should here observe that I mislaid amongst my papers the portion
of your letter containing the queries (it was a separate sheet),
and it has not as yet turned up, so that I had to depend on a
rather treacherous memory to keep the queries in my mind's eye. It
is highly probable, therefore, that I have overlooked some of them.
This circumstance was the chief cause of the delay in writing.

You are quite at liberty to make any use you please of this
communication.

WILLIAM BOYLE.

INDEX.

Absorption of moisture; 303, 304, 322
" Fertilizing substances; 268

Aeration; 269, 276

Albert Model Farm; 375

American experiments; 367

Anderson, J. F.; 112

Arrangement of drains; 173

Artesian Wells; 83

Attraction, adhesive; 301
" capillary; 302
" of soils for vapor; 304

Auger, Elkington's; 35, 246

Bache, Prof.; 65

Back water; 181

Barn cellar; 356-359

Bergen, Mr.; 199

Birmingham spades; 240

Bletonism; 36

Blodgett, Lorin; 51, 59

Bligh, Captain; 24, 27

Bogs; 91

Boning-rod; 234

Bore, form of; 129

Boring; 35, 365

Boring tools; 35, 346

Boyle, Wm.; 375

Branch pipes; 196, 378

Bricks, draining; 121, 144
" cost of; 204

Brush drains; 104, 105

Capacity of pipes; 131, 132, 134, 201

Capillary attraction; 302

Cellars, drainage of; 351-359

Challoner's Level; 235

Clay soil; 167, 329

Clays, drainage of; 322-332

Clays, cracking of; 275, 324-331

Collars; 47, 126, 127, 128, 219, 316, 320, 378

Cold from evaporation; 63, 272

Cost of drainage; 211-224, 309, 376