General Notices. 37 



though abounding in peat bogs and stagnant ponds during winter, suffers 

 much from the summer drought. The other attempts to form Artesian wells, 

 referred^ to by Mr. Sedgwick, were made near Lincoln, which, though sur- 

 rounded by fens covered with water in the winter, is not sufficiently supplied 

 during the summer. But the clays supporting the fens of the Bedford Level 

 are below the chalk ; and though there are pervious beds beneath them, which 

 rise to the north-west, yet the clays are of such enormous thickness that they 

 have never been penetrated ; and even were that accomplished, the high land 

 is so distant that intervening fissures, filled up with impervious materials, 

 might intercept the supply. Expensive sinkings have been made at Lynn, 

 and also at Boston, but, after boring through many hundred feet of clay, they 

 have utterly failed ; and, in any future operations in this district, the chance of 

 success would be very remote." (Edin. Phil. Journ., vol. xxxi. p. 426.) 



The Fire at the Tower of London. — The opinion generally entertained by 

 those who are deemed competent to judge in the matter is, that the fire 

 originated with the stoves used for heating, and that it is not at all impro- 

 bable but calamities of a similar fearful nature may be anticipated. The 

 reasons assigned are, that new modes of heating being introduced into 

 buildings not at all fitted for them, their destruction is consequently almost 

 certain. Flues and chimneys, with their adjacent walls, which stood unscathed 

 when wood or coal were used as fuel, and the security of which might be 

 guaranteed for many ages, are not suitable for these modern introductions, in 

 which large quantities of heated air are elicited as elements of destruction. 

 Besides this, the conductive power of the bricks and cement undergoes a 

 great change from the constant operation of heat and air, so that heat is re- 

 tained and conducted with greater facility. In this, in the opinion of a 

 gentleman of science, who informed the reporter he had memorialised the 

 Board of Ordnance upon the subject, to a great extent consists the secret of 

 many, of those recent conflagrations which have appalled the public and 

 destroyed so many of our public buildings. (Times, Nov. 16. 1841.) 



Merthyr Coal is strongly recommended for hothouse furnaces, and for open 

 fires where the object is a steady powerful heat without much flame, and 

 without the trouble of stirring. This coal makes no smoke, no clinkers, 80 

 tons produce as much steam as 100 tons of Newcastle coal, and it requires 

 less attendance, as it must not be stirred. The price is the same as that of 

 Newcastle coal. It is used by the Rev. Theo. Williams, Hendon ; George 

 Byng, Esq., Wrotham Park ; Thomas Harris, Esq., Kingsbury ; and Captain 

 Trotter, Dyrham Park. — Cond. 



Improved Draining-Tiles. — Agreeably to your request, I send you one of 

 my improved draining-tiles (fig. 2.), and also one of the connecting tiles, 

 and a tile with a hole in its side (fig. 3.) for joining the connecting tile, de. 



Fig. 2. Munro's Draining-Tile Fig. 3. Munro's connecting Tile. 



scribed in a communication of mine to the president of the Northamptonshire 

 Agricultural Society, and afterwards published in the Northampton Mercury. 

 I likewise send you some pieces of offal wood (short pieces between 9 in. and 

 1 ft. in length), which 1 propose being used as drain covers. You will ob- 

 serve that they are intended as covers for the mouth of a chad, or groove, or 

 gutter, in the bottom of a drain, such as is made in this county, and which I 

 shall try to describe. First, a trench of the width of 10 in. or 1 ft. is dug out 

 to nearly the same depth with a common spade ; then, in the middle of this 

 trench the workman commences with a long-bladed spade-like instrument, 

 3J in. to 4 in. broad ; the depth of this second opening, which is called the 

 chad, will, of course, be regulated according to the nature of the ground. 

 Sometimes it may be 20 in. deep, and sometimes less. Then those pieces of 



d 3 



