320 C H A P T E 1?: 51. 
the philofopher and the phyfician. This 
knowledge enabled him frequently to fug- 
geft ufeful hints ; one of which highly de- 
ferves to be mentioned, as it refpeds an 
objed; of great importance to the public. 
In the hard winter of 1756, he wrote 
Some Obfervations on preventing the 
freezing of Water in the Leaden Pipes 
of the City of London occafioned by 
the injudicious and ineffeftual method, 
pradtifed frequently, of ftrewing dung in 
ithe llreets over the pipes. Thefe were 
printed in the Gentleman s Magazine [a) for 
January 1757, p. 6. in which is pointed 
{a) The method was fimply by means of two addi- 
tional brafs cocks. One to be inferted into the leaden 
pipe, two feet before it comes into the air, guarded by a 
wooden cafe, filled up with horfe litter, and reaching near 
to the furface of the ground, and covered over, even with 
the ground, by a brick or ftone. This is to ferve as a 
flop- cock, and to be turned by the help of an iron key. 
The other cock is to be faflened to the leaden pipe in 
the open air, in any part of its length, provided it be 
fomewhat below the level of the ftop-cock. This is in- 
ferted fimply to empty the leaden pipe of all its water, 
after it has been turned oiFby the ftop-cock. From the 
defcription of this apparatus, the method of ufmg it is ob- 
Tious. 
' out 
