40 Transactions.— Miscellaneous. 
adoption of a general system of main drainage. The metropolis had 
suffered severely in the cholera visitation of 1831-2, again in 1848-9, and 
lastly in 1858-4." “The places formerly most favourable to the spread of 
the disease became quite free from it when afterwards properly drained." 
Again: “In designing a system of main drainage these points had to be 
kept in view—to provide ample means for the discharge of the large and 
inereasing water supply consequent on the universal adoption of water- 
closets, and of the ordinary rainfall and surface drainage at all times, 
except during extraordinary storms, and to afford to the low-lying dis- 
tricts a sufficiently deep outfall to allow of every house being effectually 
relieved of its fluid refuse.” 
Again: “ For centuries there had existed Sewers Commissions appointed 
by the Government, and irresponsible to the ratepayers, upon whom they 
levied rates." “The author (Sir J. W. Bazalgette) having been appointed 
engineer to the Metropolitan Board was again instructed to prepare a plan 
for the drainage of the metropolis ;’’ “and it was through the influence of 
Lord John Manners that the Board was left free to carry out their system 
of main drainage.” 
Again: “The objects sought to be attained in the execution of the main 
drainage works were—-the interception of the sewage (as far as practicable by 
gravitation), together with so much of the rainfall mixed with it as could be 
reasonably dealt with, so as to divert it from the river at London; the 
substitution of a constant, instead of an intermittent flow in the sewers; 
the abolition of stagnant and tide-locked sewers, with their consequent 
accumulations of deposit; and the provision of deep and improved outfalls 
for the extension of the sewage into districts previously, for want of such 
outfalls, imperfectly drained." 
Again: “ According to the system it was sought to improve; the London 
main sewers fell into the Thames, and, most of them passing under the low 
grounds in the margin of the river before they reached it, discharged their 
contents into that river at or about the level, and at the time of low water 
only. As the tide rose it closed the outlets and ponded back the sewage 
flowing from the high ground." 
“ The volume of pure water in the river (Thames) being at that time at 
its minimum rendered it quite incapable of diluting and disinfecting such 
vast masses of sewage." 
Again: ‘‘In the system now adopted it has been sought to remove those 
evils by the construction of new lines of sewers laid at right angles to 
those existing, and a little below their levels, so as to intercept their 
contents and convey them to an outfall fourteen miles below London 
Bridge n 
