SEW
420
SEW
i
I
manner ; for, in the first place, there will be less tendency todeposit; and in the second, when a deposit takes place, it willbe more readily removed. This is both reasonable in theory,and has been proved in practice, for the evidence of Mr.Lovick and .others, who have had opportunity of examiningthe state of- small pipes after they have been in use sometime, goes to prove that they keep themselves almost perfectlyfree from deposit. It will be perceived by the followingtable, prepared from the experiments made in the Earl-streetsewer, that the quantity of solid matter in suspension insewage-water, bears but a small proportion to the liquid, andit is therefore probable, that with a fair velocity of flowthere would be but little tendency to deposit.
Tables of Solid Matter in Suspension in the Flow.
No. 1 .—On the Extra Water-Days.
Quality of flow analyzed, and periodwhen taken.
Solid matter in one Impe-rial Gallon.
Proportions.
Soluble
Grains.
Inso-
luble
Grains.
Soluble& Inso-lubleGrains.
Solubleto Inso-luble. *
Soluble& Inso-luble toLiquid.
Greatest taken, 5J p. M.
33
19
52
2 to 1
1 to
Mean of 2 analyses, taken at\
1346
12 A.M. J
119
46
165
2£ to 1
424
Mean of 2 analyses, taken at"l
119
37
156
3| to 1
448
8J and 10J a.m. J
Least taken at 12 p.m.
111
11
122
10 to 1
574
Total .
382
113
495
Averages.
96
28
124
3£ to 1
504
When water first laid on, or 1
at commencement of over- >•
80
192
272
1 to 2J
257
flow from cisterns.j
No. 2.— On Ordinary Days.
Quality of flow analyzed, and periodwhen taken.
Solid matter in one Impe-rial Gallon.
Proportions.
Soluble
Grains.
Inso-
luble
Grains.
Soluble& InsolubleGrains.
Solubleto Insoluble.
Soluble& Inso-luble toLiquid.
Greatest mean of two analyses >taken at 12 a.m.)
114
154
114
34
71
14
148
225
128
3£ to 1
1 to473
8 to 1
646
Total.
382
119
501
127
40
167
3i to 1
The principal objections against the use of small-pipesewers are ; 1st. That if any obstruction occur in the pipe,so as to cause accumulation of deposit, the pipe rapidlybecomes completely stopped up, whereas, in the largersewers, even though obstructions may occur, they will notentirely stop the flow, or at least the accumulation must pro-ceed for a considerable period ere the entire area be filled up.2nd. That if such stoppage take place, there is no means ofready access to the sewer to examine it, and that the roadswill probably have to be broken up in several places ere thedrainage be repaired; and even then it is almost impracticableto reinstate the pipes in the same conditions as when firstlaid down. 3rd. That owing to the nicety required in lay-ing the pipes, an uniform inclination is not easily preserved,nor is there any satisfactory means of knowing when the
, r cc tiv e 1
invert is perfectly smooth ; that if the pipes be de th eform, or imperfectly laid, or if the cement with wjoints are made be allowed to project within the Pthe general surface, an obstacle is at once offered to ^ g top'which is not unlikely to cause deposit, and there ypage in the pipe. ea r fe ft '
Now, in the case of the first objection, it does a Pr th aI1sible, that a small pipe would be more rapidly hue u pposi n ^a large sewer, but yet there are some groundsthe contrary to be the case; for as the water-w y g . a n<jcontracted, so also does the scour of the stream a fim
moreover, the stream being ponded back, we shah *‘ n that
’' eadof water t0 increase 0 the power of the flow, so -be extrem'TVffi 1 , Unless the matter causing the ° bstrl ?L>ly
S he enZ t , CU , U of removal > ‘be water-way 1 ' 9 not 1*to oe entirely closed up.
able wehr C W d •° bjeCti0n m,,st be allowed to possess consd 1 ^
able weight; in case of stoppage it would in troth,™ccident° f vft rea , t H ifficultyand inconvenience to remedyin brick ’ yCt ’ at H 16 Same tlme > w e must not forget, tin tve, v rL VerS ’ lf be of smaller class, there
likefv to ^ m eans of access; and moreover, they aie ;fDine T n, S e deposit; we are inclined to think, ‘ t
teZZT h f Carefu % Jaid - *nd fairly used, they wou ^ ^
for th* ^ t0 81 fc Up * .^ Jie objection to breaking up tJje ]r bepurpose of discovering the stoppage, can scaic 7
skk ’
madJ\v'tl » n ic ieir , Pormer position, unless indeed cV )iii-made w ]th half-^ket joints, or be made of two sew^ducal pipes one laid over the other. , ,. acU ltf
and nn re fl u <red in laying the pipes, and the ! t j 0 n-
and uncertainty a tt e ndin g the Felice is certainly oh ec‘ (0v t ere 1S , 110 “ eans of ^eing the interior of the l:t Z e '°' V ‘ he W ° rk » PerfornTed, and it is notlessness ntw? 86 ’ tbat tlle cement at the joints, by : eC t-incr riff , t le wol 'kmen, is sometimes left to form P n ymg^.dge above the surface of the invert. To prevent ^
joims > il '“ns been proposed to ^
P , P , I a slightly conical form, inserting the sniad . tliis>hnw dr8t lnt0 ,ile barge end of the succeeding P‘P ’ t \>e
however. soon,., rntIlfir a % , wkwa ,. d metho d of d
heim u>’
Sj’/an'd we at, ‘ er - . “wkward
Would be, to mike rf G m . c ^ ne ^ t0 think, that abrst laying. the'bL.? P ’ pes in ‘wo pieces, as suggested >-covering them * ? an d securing their accuracy, nn - 3
Plan witl,ou, objecI' i(a '3 h ^ " Pper haIf; ' but " eitl ‘ e1 ' ”
SO long a^the laGe^he?' 10 " ° f boUSe from surface , d ^r"»e r '
we do not t],;,,i, • ^ eai s s o small a proportion to the .. .
each ; buTin ? d v * sa ble to form a separate syst^
" C ‘ ,SeS w bere the proportion of surface-*® 1 ^' -uu, uniform, 1 . esewugf■ , dee#
increased, and the house-drainage tolera y ^ ^ ^
possibly be advisable to separate them, 1 gca rcev' n ,)tintended for dry manure ; otherwise, we s . ,a ver g, "' e _ , v -e
it expedient: with reference to the size o gtoi ' 1119 ’ „e,
think it necessary to provide for extraon a
would rather have the advantage of a go° F m ,„ a cai l3<;t
irenei' 1
and the occasional and temporary ina01 )^® n |yjth the. ca ^. vV®
st allt
heavy storm, than be safe from the latterinconvenience of imperfect drainage,should advise a system of pipe-sewers,portion to the areadown for experiment in Earl-street;
eakit'S;
prc'
.
occasions the pipes are likely to be moie cal ^ ur \ n g that t j,gordinary cases, we find that on one occasion ^ h ea oC cf> {the water reached a height of 9 inches a 0 jjkely e e <>t
pipe. We would allow for such storms a ^ cg ; nonce a month, but not such as occur o y