telford, thomas(1823) report of thomas telford, esq. on effects which will be produeced on river...
TRANSCRIPT
-
8/14/2019 Telford, Thomas(1823) Report of Thomas Telford, Esq. on Effects Which Will Be Produeced on River Thames by R
1/10
This article was downloaded by: [University of Cambridge]On: 04 November 2013, At: 14:38Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales RegisteredNumber: 1072954 Registered office: Mortimer House, 37-41Mortimer Street, London W1T 3JH, UK
Philosophical Magazine
Series 1Publication details, including
instructions for authors and
subscription information:http://www.tandfonline.com/loi/
tphm12
VIII. Report of Thomas
Telford, Esq. on the
effects which will
be produced on the
river thames by the
rebuilding of London
BridgeThomas Telford
a
a24, Abingdon-street, Westminster
Published online: 23 Jul 2009.
To cite this article:Thomas Telford (1823) VIII. Report of Thomas
Telford, Esq. on the effects which willbe produced on the river thames
by the rebuilding of London Bridge , Philosophical Magazine Series 1,
62:303, 21-28, DOI: 10.1080/14786442308644372
To link to this article: http://dx.doi.org/10.1080/14786442308644372
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy ofall the information (the Content) contained in the publicationson our platform. However, Taylor & Francis, our agents, and ourlicensors make no representations or warranties whatsoever as
http://dx.doi.org/10.1080/14786442308644372http://www.tandfonline.com/action/showCitFormats?doi=10.1080/14786442308644372http://www.tandfonline.com/loi/tphm12http://www.tandfonline.com/loi/tphm12http://dx.doi.org/10.1080/14786442308644372http://www.tandfonline.com/action/showCitFormats?doi=10.1080/14786442308644372http://www.tandfonline.com/loi/tphm12http://www.tandfonline.com/loi/tphm12 -
8/14/2019 Telford, Thomas(1823) Report of Thomas Telford, Esq. on Effects Which Will Be Produeced on River Thames by R
2/10
to the accuracy, completeness, or suitability for any purposeof the Content. Any opinions and views expressed in thispublication are the opinions and views of the authors, andare not the views of or endorsed by Taylor & Francis. Theaccuracy of the Content should not be relied upon and shouldbe independently verified with primary sources of information.
Taylor and Francis shall not be liable for any losses, actions,claims, proceedings, demands, costs, expenses, damages, andother liabilities whatsoever or howsoever caused arising directlyor indirectly in connection with, in relation to or arising out of theuse of the Content.
This article may be used for research, teaching, and privatestudy purposes. Any substantial or systematic reproduction,
redistribution, reselling, loan, sub-licensing, systematic supply,or distribution in any form to anyone is expressly forbidden.Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions
Downloadedby[UniversityofCambridge]a
t14:3804November2
013
http://www.tandfonline.com/page/terms-and-conditionshttp://www.tandfonline.com/page/terms-and-conditions -
8/14/2019 Telford, Thomas(1823) Report of Thomas Telford, Esq. on Effects Which Will Be Produeced on River Thames by R
3/10
M r . T e l f o r d on the E~ects o f removing Lond on Bridge 21b i b l e t h a t t h e y h a v e n o t b e e n f o r m e d b y c r y st al li za t io n i nc o o l i n g f r o m a s t a te o f f u si o n , b u t h a v e r e c e i v e d t h e i r s u c ce s -s iv e in c r e m e n t s b y r e d u c t i o n o f t h e o x i d e d i s so l v e d ill t h e s la ga r o u n d t h e m : a m o d e o f f o r m a t i o n t o w h i c h w e m u s t h a v er e c o u r s e fo r c o n c e i v i n g r i g h t l y t h e f o r m a t i o n i n n a t u r e o f m a n yo t h e r m e t a l l i c c r y s t a l s .
S i n c e t h e d a t e o f th i s c o m m u n i c a t i o n , t h e l i b e ra l i t y o f M r .A n t h o n y H i l l , o f M e r t h y r T y d v i l , h a s s u p p li ed m e w i th al a r g e r q u a n t i t y o f t h e s la g w h i c h f o r m e d t h e s u b j e ct o f m yf ir st e x p e r i m e n t s , a n d h a s e n a b l e d m e t o d e t e r m i n e t h e s p e -c i fi c g r a v i t y o f m e t a ll ic t i ta n i u m t o b e 5 3. F o r t h is p u r p o s e ,t h e v i t re o u s p a r t w a s fu s e d w i th a m i x t u r e o f b o r a x a n d s u b -c a r b o n a t e o f so d a i n a b o u t e q u a l q u a n ti ti e s, a n d w a s t h e n d i s-s o l v e d i n m u r i a ti e a c id , w h i c h a l so r e m o v e d a q u a n t i t y o f m e -t a ll ic i ro n , a n d l e ft t h e t i t a n i u m f r e e d f r o m e x t r a n e o u s m a t t e r .T h o u g h g r e a t p a r t o f w h a t w a s t h u s o b t a in e d f r o m t h e i n -t e r i o r o f , t h e s la g w a s i n .a p u l v e r u l e n t s t a te , t h e q u a n t i ty ,w h i c h a m o u n t e d t o 3 2 g r a m s , a n d d i s p la c e d 6 0 4 o f w a t e r ,w a s s u f f ic i en t t o p r e c l u d e a n y c o n s i d e r a b l e e r r o r .
I h a v e m o r e o v e r l e a r n e d t h a t m e t a l li c c u b e s , s im i l a r t o t h o s ew h i c h I h a v e a b o v e d e s c r i b e d mad e x a m i n e d , w e r e m o r e t h a n2 0 y e a r s s in c e o b s e r v e d i n a s la g a t t h e C l y d e i r o n - w o r k s i nS c o t l a n d ; t h a t a s m a l l q u a n t i t y h a s a ls o b e e n m e t w i th at t h eL o w M o o r i ro n - w o r k s , n e a r B r a d f o r d in Y o r k s h i r e ; a n d a tt h e P i d d i n g i ro n - w o r k s, n e a r A l f r e to n i n D e r b y s h i r e ; a n dt h a t s o m e g o o d s p ec im e n s h a v e b e e n o b t a in e d f r o m P o n t y -p o o l i n M o n m o u t h s h i r e ; b u t i t d o e s n o t a p p e a r t h a t a n y o n eh a s a s c e r t a i n e d o r e v e n s u s p e c t e d t h e r e a l l l a t u r e o f t h is s in -g u l a r p r o d u c t .V I I I . R e p o r t o f TH OM AS T E L r o a n , E sq on the EitTects wh ichw i l l be produced on the R ive r Tham es b the Reb u i ld ing ~o fL o n d o n B r id g e
N c o n s e q u e n c e . o f th e a u th o r it y , g i v e n m e b y t h e r e s o l u t io nI o f t h e C o m m i t te e f o r l e tt in g t h e B r i d g e - H o u s e E s t a te s ,d a t e d t h e 7 t h o f M a r c h la st , I i m m e d i a t e ly t o o k m e a s u r e s t og e t a n a c c u r a te s u r v e y m a d e o f t h e r iv e r , i ts b a n k s a n d a p -p e n d a g e s . F o r t hi s p u r p o s e I e m p l o y e d t w o p e r s o n s e x p e -r i e n c e d i n m a k i n g s i m i l a r s u r v e y s , v iz . o n e fo r t h e d i s t ri c t f r o mL o n d o n . B r i d g e t o P u t n e . y , a n d t h e o t h e r f r o m P u t n e y t oT e d d m g t o n L o c k ; a n d m o r d e r to e n s u r e a c c u r a cy a n d p r o -p e r c o n n e x i o n a n d u n i f o r m i t y , I c a u s e d o n e o f n ay o w n a s sis t-a n t s , a l so a c c u s t o m e d t o r i v e r s u r v e y s , t o c a r r y le v e ls fr o mL o n d o n B r i d g e to T e d d i n g t o n L o c k , a n d I h a v e m y s e l f s u-p e r i n t e n d e d
Downloadedby[UniversityofCambridge]a
t14:3804November2
013
-
8/14/2019 Telford, Thomas(1823) Report of Thomas Telford, Esq. on Effects Which Will Be Produeced on River Thames by R
4/10
2 2 M r . T e l f o r d o n the l~ffec ts on the Th am esp e r i n t e n d e d a n d o c c a s io n a l ly i n s p e c te d th e p r o c e e d i n g s :h a v e a l s o r e c e i v e d t h e t i d a l o b s e r v a t io n s m a d e a t d i f f e re n tt i m e s a t s e v e r a l s t a t i o n s u p o n t h e r i v e r .I n o r d e r t o p r o c e e d w i th r e g u l a r i t y , I s h a l l a d o p t t h e f o l-l o w i n g a r r a n g e m e n t i n t r a c i n g t h e e ff ec ts w h i c h w o u l d b e p r o -d u e e d to t h e w e s tw a r d a n d a ls o t o t h e e a s tw a r d o f L o n d o nB r i d g e , i f t h e p r e s e n t e d i fi ce , w h i c h c o n s ti tu t e s a d a m o f f r o m1 f oo t 1 i nc h t o 5 f e e t 7 i nc he s , o r 4 f e e t 4 i nc h e s on a n a ve r -a g e, w e r e r e m o v e d , a n d i n i t s s te a d a n e w b r i d g e , w i th c o m -p a r a t i v e l y l it tl e o b s t r u c t i o n , w e r e s u b s t i tu t e d :1 s t. O b s e r v a t i o n s o n t i le c o m p a r a t i v e st a te o f h i g h w a t e r ,f o u n d e d o n t h e s u r v e y s a n d l ev e ls l a t e ly t a k e n , a n d t h e t id a lo b s e r v a t io n s m a d e i n 1 8 2 0 , 1 8 2 2 , a n d 1 8 2 3 ; n d f u r t h e r ,w h a t is li k el y t o ta k e p l a c e i f L o n d o n B r i d g e b e r e m o v e d .2 d l y . S i m i l a r o b s e r v a t io n s a s r e g a r d s t h e s ta te o f l o ww a t e r .3 d l y . A s t o t h e e f fe c t s w h i c h t h e a f o r e s a i d c h a n g e s a r e l ik e l yt o p r o d u c e u p o n t h e n a v i g a t io n , b r i d g e s , b a n k s , w h a r f s, s h o re s ,a n d a d j a c e n t p r o p e r t i e s .
_ First A s to t h e S t a t e o f t h e R i v e r a t H i g h W a t e r .I t a p p e a r s f i o m t h e t a b le o f o b s e r v a ti o n s o f t h e h e i g h t o ft h e t i d e s a t t h e s e v e r a l b r i d g e s i n 1 8 2 0 a n d 1 8 2 2 t h a t t h ea v e r a g e f id l t h r o u g h L o n d o n B r i d g e a t h i g h w a t e r w a s f r o m8 t o 1 3 i n c h e s ; t h a t b y t h o s e o f 1 8 2 3 , s in c e t h e r e m o v a l o ft h e w a t e r - w o r k s , t h e f i l l i n s t e a d o f 8 i n c h e s is n o w o n l y f r o m3 t o i n c h e s ; I t h i n k t h e r e f o r e i t i s f a i r t o c o n c l u d e t h a t w i tha s ti ll le s s ob s t r u c t e d w a t e r w a y t he r e w i ll be l i tt l e o r no fa l la t h i g h w a t e r , a n d t h a t h e r e a f t e r h i g h t id e s i n t h e w e s t e r n
p a r t s o f t h e c i ty w i ll e v e n i n c a lm w e a t h e r b e a t l e a st o n t h es a m e l ev e l a s b e l o w b r i d g e . I f in d t h a t t h e l e v e l o f t h e w h a r f sb e l o w b r i d g e i s f r o m 2 t o 4 f e e t a b o v e t h e T r i n i t y d a t u m ,a n d t h a t th o s e o f 2 ~ fe e t a r e o c c as i o n a ll y f lo o d e d . T h e a v e r -a g e l e v el o f t h e w h a r f s a b o v e b r i d g e i s f r o m 1 ~ to 2 f e e ta b o v e t h e T r i n i t y d a t u m ; a n d t h e e x t r a o r d i n a r y f lo o d o f1 8 2 1 , w h i c h r o s e a t T e d d i n g t o n 7 f ee t, r o s e a t P u t n e y o n l y2 f e et, a n d a t L a m b e t h 1 f o o t 11 i n c h e s a b o v e t h e s a id d a t u m .T h e r e f o r e i t a p p e a r s t h a t t h e r e is m o r e r e a s o n a t p r e s e n t t od r e a d th e e l e v a ti o n a r is in g f r o m t h e t i d e b e l o w b r i d g e , t h a nf r o m fl oo d s a b o v e ; a n d t h a t t h e f lo o d s o f t h e T h a m e s a r e n o ts u ff ic ie n t, i n t h e p r e s e n t s ta t e o f t h i n g s , t o fil l t h e l a g o o n o rp o n d a b o v e t h e n a r r o w s o f t h e b r i d g e t o t h e h e i g h t w h i c hs o m e o f t h e t i d e s d o b e lo w , a n d w h i c h , t h e r e is r e a s o n t o b e -l ie v e t h e y a ls o w o u l d a b o v e , w e r e t h e c h a n n e l u n o b s t r u c t e d .B u t i t m a y b e s u p p o s e d th a t t h e q u a n t it y o f t i d e c o m i n g ina t t h e N o r e b e i n g g i v e n , t h e a d d i t io n a l s p a c e p r o v i d e d fo r i tb y
Downloadedby[UniversityofCambridge]a
t14:3804November2
013
-
8/14/2019 Telford, Thomas(1823) Report of Thomas Telford, Esq. on Effects Which Will Be Produeced on River Thames by R
5/10
J) om the Removal o f Lon don Bridge. 23b y . o p e n i n g t h e u p p e r p a r t o f th e r i v e r w i ll p r e v e n t i t f r o mr x s m g s o h i g h a s i t n o w d o e s n e a r t h e b r i d g e , a n d t h a t t h e r e -f o r e n o t o n l y i s t h e r e a p r o b a b i l i t y o f n o g r e a t e r e l e v a ti o n o c -c u r v i n g t h e r e t h a n a t p r e s e n t , b u t t h a t it w i ll, ir~ s i m i l a r c i r -c u m s t a n c e s, b e l o w e r b e l o w b r i d g e - - c o n s e q u e n t l y t h a t n od a n g e r c a n a ri s e a b o v e . T o t h is i r e p ly , t h a t w h e n i t is h i g hW a t er a t t h e N o t e , w e h a v e it , w i t h in t w o h o u r s , h i g h w a t e r a tL o n d o n B r i d g e , a t t h e d i st a nc e o f t b r ty m i l e s ; s o t h a t t h eh i g h w a t e r p a s s e s u p a t th e r a t e o f t w e n t y m i le s p e r h o u r : s om u c h m o r e v a p id l y t h a n a n y k n o w n v e lo c i t y o f t h e r i ve r , t h a ti ts e f fe c ts a r e n o t t o b e a c c o u n t e d t b r b y t h e f l o w i n g o f t h e c u r -r e n t m e r e l y , a s m a y b e s u p p o s e d t h e c a s e in f i ll in g u p t h ep o n d t o T e d d i n g t o n t h ro u g h th e a r ch e s o f L o n d o n B r i d g e .I n th i s l a s t c a se w e h a v e l e v el le d a l o n g t h e b a n k s o f t h er i v e r, a n d fi n d, a f t e r c o r r e c t i n g t h e m a r k s e x p r e s s i n g T r i n i t yd a t u m , t h a t th e l o w e s t s u r fa c e o f h i g h w a t e r is b e t w e e u P u t -h e y a n d K e w ; t h a t i t r is es a b o u t o n e i b o t t o T e d d i n g t o n , a n dn e a r l y a s m u c h a t L o n d o n D o c k s : b u t t hi s i s l ia b le t o c o n -s i d e r a b le v a r i a ti o n . T h e r is e i n t h e u p p e r p a r t o f t h e r i v e rp o n d m a y b e e as il y a c c o u n t e d f o r b y t h e a c c u m u / a t io n o f t h ef r e s h w a t e r s o f t h e r i v e r o v e r a n d a b o v e w h a t is t i d a l w a t e r .T h e f al l f r o m L o n d o n t o w a r d s P u t n e y s ee m s to s ho w t h a t th et id e h a s n o t t im e , t h r o u g h t h e c o n t r a c t e d p a s s ag e , t o fil l u pt h e p o n d a b o v e b r i d g e to t h e l o w e r l ev e l.F r o m L o n d o n B r i d g e t o B l a c k w a ll t h e h i g h w a t e r s e em s ,f r o m t h e o b s e r v a t io n s , t o b e l e v e l : t h e q u a n t i t y o f w a t e r r e -q u i r e d t o fi ll u p th i s d i f f e r e n c e o f l e v e l i s, a f t e r a ll , s os m a l l, t h a t w i t h a n u n o b s t r u c t e d w a t e r w a y it w o u l d e v i d e n t l ym a k e n o d i f f e r ,e n ce w o r t h y o f n o t i c e i n t h e l ev e l o f t h e t i d eb e l o w b r i d g e , e v e n w e r e it s u b t r a c t e d i i o m t h e m a s s t h a t l ie sb e tw e e n L o n d o n B r i d g e a n d t h e N o t e . W h e r e a s c o n s id e r -i n g th e g r e a t r a p i d i ty w i th w h i c h t h e l o w e r p a r t o f th e r i v e ri s f i l l e d b y t h e t i d e , i t i s c l e a r t h a t a n u n o b s t r u c t e d t i d e w o u l df i l l u p t h i s t r i f l i n g i n c r e a s e i n a t l e a s t a s l i t t l e t i m e a s t h e p r e -s e n t p e r i o d .B u t t o r e n d e r t h is a m a t t e r o f c a l c u l a t io n : w e fi n d t h ea v e r a g e b r e a d t h o f t id e - w a t e r a t t h e N o r e t o b e 3 m i l e s ; a t( 3 r a v e s e n d h a l f a m il e, t h e d i s t a n c e b e i n g 1 8 m i l e s ; w h i c h , a t6 0 0 0 f e e t p e r g e o g r a p h i c a l m i t e , w i t h 1 5 ,*~ et o f t i d e , g i v e s t ~ o mt h e N o t e to G r a v e s e n d 1 7 ,0 0 0 m i l li o n s c u b i c ~het o f t i d e -w a t e r : a t L o n d o n B r i d g e , t a k i n g t h e b r e a d t h a t 1 0 00 f e e t a n d3 0 0 0 a t G r a v e s e n d , w e h a v e i n 2 4 m i l e s, a n d w i th t b e s a m ed e p t h , 4 3 2 0 m i l li o n o f c u b i c f e et , o r 1 - t h a d d i t i o n a l t i d e - w a -t e r . T h e r e r u n a t p r e s e n t t h r o u g h L o n d o n B r id g e , b e tw e e nt h e l o w e s t e b b s a n d h i g h w a t e r o f o r d i n a r y s p r i n g s (o r l - f e e tt i d e s ) a b o v e b r i d g e , 0 ~8 2 m i ll io n s c u b i c f e e t ( 5 8 ~ , 3 ~ e , 7 1 0 ) ;a n d
Downloadedby[UniversityofCambridge]a
t14:3804November2
013
-
8/14/2019 Telford, Thomas(1823) Report of Thomas Telford, Esq. on Effects Which Will Be Produeced on River Thames by R
6/10
21~ M r . T e l f o r d on t he E f f ec t s on the Tha me sa n d i f L o n d o n B r i d g e b e r em o v e d , so t h a t t h e r e b e n o m a -t e r ia l d a m a t l o w w a t e r , w e h a v e a l so t o f il l t h e p o n d n o wc a u s e d b y th a t d a m . T h i s p o n d is f ro m 4 t o 6 f e e t d e e p a tt h e b r i d g e , a t l ow w a t e r ; a n d w e f i n d t h a t t h e l ev e l o f l o ww a t e r a b o v e b r i d g e m e e t s t h e b o t to m o f t h e T l m m e s b e tw e e nP u t n e y a n d K e w , v iz . 10 m i le s a b o v e b r i d g e : t a k i n g th i s a st h e h e a d o f t h e p o n d , t h e a v e r a g e b r e a d t h a t 6 0 0 f e e t a t l o ww a t e r , t h e m e a n d e p t h t o b e f i l l e d a t 2 f e e t , w e h a v e a n a d d i -t i o n o f 7 5 m i l li o n s o f c u b i c f e et , o r 1 - 5 7 t h o f t h e q u a n t i t y o ft id e - w a t e r b e t w e e n L o n d o n a n d G r a v e s e n d , o r o n l y 1 - 2 8 4 t ho f t h e w h o l e q u a n t i ty o f t id e - w a t e r w i t h in t h e N o t e ; t h e r e f o r et h e w h o l e w a t e r w h i c h m u s t p a s s t h e N e w B r i d g e , t o r a i s e t h eu p p e r r i v e r t o t h e l e v el o f h i g h w a t e r b e l o w b r i d g e , is 6 7m i l li o n s, o r 1 - S 2 d o f t h e e n t i r e q u a n t i t y o f t i d e - w a t e r w i t h int h e N o t e b e lo w b r id g e .I t i s a w e l l- k n o w n f a c t t h a t t h e ti d e i n n a n o w c h a n n e l s w i thf u n n e l - s h a p e d m o u t h s , o r a g a i n s t c o a s ts w h i c h o p p o s e it s r e -g u l a r c o u r s e, r i se s c o n s i d e r a b l y h i g h e r t h a n a t t h e p l a ce sw h i c h a r e s i tu a t e d i n r e ti r ed b a y s , o r u n d e r th e w a k e o f p r o -j e c t i n g p o i n t s : t h u s t i le A t l a n t ic t i d e r u n n i n g u p t h e C h a n n e lr is e s 6 o r 7 f a th o m s a g a i n st t h e F r e n c h c o a s t n e a r S t. M a l oa n d H a v r e ; w h i le o n ti le o p p o s i te E n g l i s h c o a st , s t P o r t -l a n d a n d P o o l e , w e h a v e o n l y o n e f a t h o m r i se . I n S t. G e o r g e sC h a n n e l , t h e t id e s a t M i l fo r d a n d a l o n g th e W e l s h c o a s t r i s ef o u r f a t h o m s ; o n t h e o p p o s i te I r i s h c o a st , f r o m C a r n s o r eP o i n t to W i e k l o w , h a r d l y o n e f a th o m . M a n y s im i l a r i n st an c e sm i g h t b e g iv e n . A g a i n , a s t o f u n n e l - s h a p e d m o u t h s : t h es p r i n g - t i d e a t t h e e n t r a n c e o f B r i s t o l C h a n n e l r is e s ~ 2 to ~4~f e e t ; b u t a s t h a t c h a n n e l c o n t r a c t s i n b r e a d t h , t h e v e l o c it y a n dv e r t ic a l r is e i n c r e a se i n p r o p o r t i o n so m u c h , t h a t in K i n g R o a di t r is e s b e t w e e n 7 a n d 8 t h th o m s . M a n y o t h e r s im i l ar i n -s ta n c e s m a y b e s h o w n . A s m a y b e p e r c e i v e d b y ti le p o s i ti o no f t h e b a n k s o f t h e T h a m e s m o u t h , t h e f lo o d - ti d e c o m e s f r o mt h e N . E . o r G e r m a n s e a : a t h a l f p a s t el e v e n i t is h i g h w a t e r a tH a r w i c h , K e n t is h K n o c k , a n d M a r g a t e ; t h e o s ci l la tio n o rr i s e a t s p r i ngs i s t i: om 15 t o 16 f e e t ; a t t w e l ve it is h i gh w a t e ra t t h e N o r e ; a n d a l t h o u g h t h e r is e t h e r e is o n l y 1 4 t~ et, y e ti n t h e S w a l e , w h i c h i s i n t h e d i r e c t c o u r s e o f t h e t i d e , t h e r i s ei s 17 t o 21 t e e t a t ha l f - pa s t t w e l ve .T h e g e n e ra l se t o f th e c u r r e n t r u n n i n g u p t h e T h a m e s f o r m sa b r a n c h w h i c h a t t h e N o r e a t n o o n r is es , a s w e h a v e s aid ,1 4 t~ e t ; b u t f ro m t h e n c e t h e f u n n e l - s h a p e p r o d u c e s a g r a d u a li n c r e a s e i n t h e o sc i ll at io n u n t il w e m - riv e n e a r L o n d o n : t h a ta t G r a v e s e nd , a t one , t he r i s e is 16 f e e t ; a t ~ vV oo lw ic h, a tt h r e e - q u a r t e r s p a s t o n e , i t is 1 8 f e e t ; a t I ) e p t f o r d , a t t w oo c l o c k , w e h a v e 1 8~ t ~ e t; b u t a t B i l li n g s g a t e , a t a q u a r t e rp a s t
Downloadedby[UniversityofCambridge]a
t14:3804November2
013
-
8/14/2019 Telford, Thomas(1823) Report of Thomas Telford, Esq. on Effects Which Will Be Produeced on River Thames by R
7/10
f r o m the Rem oval o f Londo n Bridge. 25p a s t t w o o c l o c k , t h e r e i s a ri s e o f 17 f e e t o n l y . T h e a c t i o no f t h e t id e i s n o w a f f ec t e d b y t h e b r i d g e s , t h e r e g u l a r p r o g r e s so f t h is w a v e b e i n g c h e c k e d , a n d t h e s u r f ac e o f t h e h i g h w a t e rd e c l in e s a l l t h e w a y t o P u t n e y , w h e r e i t is h i g h w a t e r a t aq u a r t e r p a s t t h r e e o c l o c k ; b u t f r o m t h e n c e a g a i n t h e r e is ar is e o f o n e f o o t t o T e d d i n g t o n , w h e r e i t is h i g h w a t e r a t t h r e e -q u a r t e r s p a s t fo u r . H e n c e o b s e r v e t h a t f i o m B i l l in g s g a t e t oT e d d i n g t o n t h e w a v e p a s s es a t t h e r a t e o f 8 m i le s p e r h o u ro n l y ; w h i le b e l o w B i l li n g s g at e t h e s a m e w a v e o f h i g h w a t e rp a s se s a t t h e r a t e o f 2 0 m i le s p e r h o u r , o r m o r e p a r t i c u l a r l yTime.
M i le s . H o u r M i nut e s. M i le s .F r o m t h e N o r e t o G r a v e s e n d 18 in 1 0 is 1 8 p e r h o ,W o o l w i c h 15 - - 0 - - 2 0: D e p t i b r d 4 ~ = 0 - - 2 6B i l l i n g s g a t e 0 - 1 6S w a n S t a i r s, a l o s s o f 1 0 mP u t n e y 7 i n 5 0 ~ 8T e d d i n g t o n 11 - - 1~ 0 ~ 7 ~i t is o b v i o u s t h e n t h a t t h i s r a p i d d i m i n u t i o n o f t h e v e l o c i t y o fh i g h w a t e r is c a u s ed b y t i le n a r r o w a t L o n d o n B r i d g e , a n dt h a t , w e r e t h a t o b s t r u c t i o n r e m o v e d , t h e r e is e v e r y r e a s o n t ob e l i ev e t h e v e l o c it y i n t h e u p p e r r i v e r w o u l d b e g r e a t l y i n -c r e a s e d .I t n m s t a l s o b e o b s e r v e d t h a t t h e f al l o r d i f f e re n c e o f h e i g h tb e t w e e n t h e s u rf a ce s a b o v e a n d b e l o w b r i d g e a t h i g h w a t e rm u s t n o t a l o n e b e t a k e n a s th e p r o p e r m e a s u r e o f t h e o b s t r u c -t io n , a n d u s e d a s a d a t u m t h r o u g h o u t a c a l cu l a ti o n , b e c a u s et h e tM 1 t h r o u g h t h e w h o l e t id e i s m u c h g r e a t e r . I n o n e v e r ym o d e r a t e sp r in g - t i d e , w h i c h I o b s e r v e d o n t h e 2 6 t h o f M a yl a st , w h e n t h e t h ll a t h i g h w a t e r w a s o n l y 5 i n c h e s , t h e f a l lt h r o u g h m o s t o f t h e p r e c e d i n g p a r t o f th e t id e h a d b e e n 1 4i n c h e s .T h e h i g h w a t e r w i ll t h e r e f o r e g o u p t o t h e h e a d o f t h e t i d e-w a y m o r e s p e e d i l y , a n d w i l l r i s e h i g h e r t h a n a t p r e s e n t .
Secondly, O f lhe lgiver at Lo w lValer .T h i s w a t e r m u s t a ls o r e t u r n w i t h g r e a t e r v e lo c it y, a n d t h e
r e m o v a l o f t h e b r i d g e w ilt n o t o n l y p e r m i t t h e i n c r e a s e d h e a dt o p a s s o f f a t t h e e b b , b u t l ik e w i se t h a t p o r t i o n w h i c h is n o wr e t a i n e d b y t h e o b s t r u c t io n .W e r e t h e f lo o d ti de n o t t o r e t u r n , a n d t h e s t r e a m o f t h er i v e r t o c e a s e , t h e b e d w o u l d e x h i b i t a s e ri e s o f p o n d s a t l e v el s,g r a d u a l l y i n e r e a si n ~ i n e l e v at io n a s w e u a s s to t h e w e s t w a r d ;o f w h i c h t h e f i rs t w o u h t e x t e n d t o B a t t e r s e a B r i d g e , h a w n g as h o a l a t * W e s t m i n s te r B r i d g e , o n w h i c h t h e r e w il~ b e l it tl e o rV o l . 6 2 . N o . 3 0 3 . July/ 1 8 2 3 . D n o
Downloadedby[UniversityofCambridge]a
t14:3804November2
013
-
8/14/2019 Telford, Thomas(1823) Report of Thomas Telford, Esq. on Effects Which Will Be Produeced on River Thames by R
8/10
2 6 M r . T e l t b r d o n t tae F,l ;. c ls on th e ~7~am esn o w a t e r , a n d n e a r l y 2 0 0 0 y a r d s in l e n g th . T h e s e c o n d p o n d ,f r o m B a t t e r s e a t o P u t n e y , w o u l d b e 1 6 in c h es h ig i m r t h a nt h e f o r m e r . A t P u m e y B r i d g e w o u ld b e a r is e o f 1 7 in c he s.A b o v e P u t n e y t o M o r t l a k e is a s h al lo w c h a n n e l w i th s m a l lp o o l s ; i n t h e d e e p e s t p a s s a g e a c r o s s t h e b a r s t h e r e is n o w l es st h a n 8 f e et o f w a t e r . M o r t l a k e is t h e n e x t p o n d , t w o m i l e s i nl e n g t h . I t s s ur K tc e is l e v e l w i t h t h e p r e s e n t l o w w a t e r a t L o n -d o n B r i d g e ; b u t b e t b r e t h e c o n s t r u c ti o n o f t h a t w o r k i t w o u l d ,a s i ts n a m e i m p l ie s , h a v e b e e n a d e a d o r s t a g n a n t l a k e a t l o ww a t e r. T h e o t h e r p o n d s w h i c h a re h i g h e r t h a n t h e p r e s e n tl ow w a t e r m a y b e o b s e r v e d in t h e g e n e r a l s ec ti on . T h e d e p t ho v e r t h e b a r i s n o w h e r e l e s s t h a n 9 l- t b et , o r n l o r e t h a n 4~ t ~ et ;b u t th i s d e p t h is w i t h s o m e d i ff i cu l ty s u l il c ie n t a t p r e s e n t f o rn a v i g a t i o n t o t h e lo c k s a t T e d d i n g t o n .W e r e t h e r iv e r w a t e r to b e r u n o f f a b o v e b r id g e , t hi s n a v i-g a t i o n m u s t c e a se , un ]e s s a n e w c h a n n e l b e e x c a v a t e d t h r o u g ht h e s h o M s : i n d e p e n d e n t o f t h e d e p r e s s i o n i n t h e l o w e r p o n dw h i c h f il e N e w B r i d g e w i ll p e r m i t , a l o n g e r t i m e w i ll b e g i v e nf o r t h e e b b t o e m p t y t h e u p p e r r e a c h es , a s w e m a y s e e b y i n -q u i r in g w h e t h e r th e o b s t r u c ti o n o f L o n d o n B r i d g e o cc a s io n sa n y r e m a r k a b l e d e v i', t {o n f l ' o m t h e p r o g r e s s o f t h e e b b , a s w eh a v e j u s t f o u n d i t t o d o i n t h e c a s e o f t h e f lo o d t id e , w h e r e b yw e f o r m s o m e j u d g e m e n t o f t h e p r o b a b l e r e st fl t o f i ts r e m o v a lw i t h r e s p e c t t o t h e v e l o c it y o f t h e e b b s t re a m .A I l o w i n g th e r e t b r e t h a t t h e t it l e a t th e N o r e o c c u p i e s 6 h o u r s1 6 m i n u t e s , o r t h e r e g u l a r h a l f t it le , w e f in d t h a t l o w w a t e rp r o c e e d s ~ T im e .M iles. Ho ur. M inutes. MilesF r o m t h e N o r e t o G r a v e s e n d 18 in 1 g 4 ~ 1 3 p e r h o .
\ V o o l w i c h 1 5 ~ 1 8D e p t f o r d 6 } ~ 0 8 7 } 1 0 gB i l l i ng sg a t e 4. ~ 0 22 10O l d 8 w a ' ,b a l o s s o f 2 0\V e s tm iu s te r ~2 in 0 ~o2,~ t5P u tn e y 5-,} - - 1 5 , t3-}T e d d i n g t o n 11 - - 3 2 0 3.}w h i c h e x h i b i t s t h e s a m e r a p i d c hm ~ g es o f v e l o c it y c a u s e d b yt h e b r k l g e a s i n t il e c a s e o f f lo o d .\ e r e t h e b r i d g e rem < >v ed , t h e r e f o r e , it is e v i d e n t t h a t t h ev e l o c i ty o f e b b a b o v e b r id g e w o u l d m a t e r i a l l y i n c re a s e , t h e t h n eo f lo w w a t e r b e e a r li e r t it a n a t p r e s e n t , th e d r a i u a g e o f th eu p p e r p o nd .s m o r e c o m p l e t e , a n d t h e n a v i g a t io n w h i c h is l :o wp r a c t i c a b le u p t o T e d d m g t o n w o u l d c e as e t oo e a r l y n e a r t h a tp l a c e . T /K rd ly , l{~ lCfects o b e pro du ce d .A t : d t as t~ y , f i ' o m t h e f o r e g o i n g s t a t e m e n t o f i h ct s i t h a s b e e ns h o w n
Downloadedby[UniversityofCambridge]a
t14:3804November2
013
-
8/14/2019 Telford, Thomas(1823) Report of Thomas Telford, Esq. on Effects Which Will Be Produeced on River Thames by R
9/10
-
8/14/2019 Telford, Thomas(1823) Report of Thomas Telford, Esq. on Effects Which Will Be Produeced on River Thames by R
10/10
28 Observations on tak ing dow n an do v e r f l o w e d , p a r t l y b y l a n d f lo o d s , b u t c h ie f ly b y h i g h t id e s ,w h i c h r i s e a b o v e a t b o t h i g h e r B elo w b r i d g e t h a n t h e y d o a tp r e s e n t a b o v e b r i d g e : t h e e v il w i ll t h e r e tb r e b e p r o p o r t i o n a b l yi n c r e a s e d b o t h ill d e g r e e a n d f r e q u e n c y . B u t b e s id e s t h ec o m m o n o p e r a t i o n s o f l a n d f lo o d s a n d t i de s i n c a l m w e a t h e r,a l l t h e r i v e r a b o v e b r i d g e w i ll , w h e n t h e d a m i s r e m o v e d , b ef u r t h e r e x p o s e d t o t h e i n f lu x o f h e a v i e r w a v e s d r i v e n f i ' o m t h eN o r e , w i t h s t o r m s f i' om th e n o r t h w a r d , w h i c h h -~ ve h i t h e r t ob e e n c h e c k e d b y t h e a h n o s t s ol id m a s s o f th e u p p e r p a r t o fL o n d o n B r i d g e . T h e s e o b s e r v a ti o n s a p p l y t o a ll t h e b a n k sa n d l ow g r o u n d s o n e a c h s id e o f f ile r i v e r f i'o m W e s t m i n s t e rt o T e d d i n g t o n , a n d w h i c h a r e v e r y ex t e ns iv e .I n s t a n c e s o f s u c h i n fl u x a n d r is i n g o f t h e t id e h a v e b e e na l re a d y m e n t i o n e d , a n d a n o t h e r h a s c o m e to m y k n o w l e d g ew h i l e e n g a g e d i n t h e p r e s e n t s u r v e y . _At t h e C a s h e n r i v e r i nK e r r y , w h i c h f al ls i n to t h e s ea n e a r t h e m o u t h o f t h e S h a n -n o n , a b a r h a s b e e n l a te l y c u t a c r o s s t o m a k e a m o r e d ir e c tn a v i g a t i o n : t h e u p p e r r i v e r h a s t h e r e b y b e e n l o w e r e d t w o o rt h r e e f e e t a t l o w w a t e r , a n d a t h i g h w a t e r r a i s e d s o a s t o o v e r -f lo w t h e m a r s h e s m o r e t h a n b e f o r e ; a n d t h e d i r e ct s t r e a m i sn o w c u t t in g a c h a n n e l t h r o u g h t h e s a n d y s h o a ls a b o v e t h eb a r . T h i s i n f o r m a t i o n I r e c e iv e d f r o m t h e a b l e e n g i n e e r( M r . N i m m o ) w h o a d v is e d t h e m e a s u re .T h e E ffe cts E a s tw a r d o f tlw B r i d g e . ~ N o l o n g i t u d i n a l o rc r o s s s e c ti o n s h a v i n g b e e n t a k e n t o t h e e a s t w a r d o f t h e b r i d g e ,I h a v e n o a c c u r a t e k n o w l e d g e o f t h e s ta te o f t h e r i v e r b e d ,a n d c a n t h e r e fo r e o n l y o b s e r v e g e n e r a l ly , t h a t m y i n v e s ti g a .t io n s h a v e le d m e t o t h e c o n c l u s i o n t h a t m o r e w a t e r w i ll p a s sw i t h a g r e a t e r v e l o c it y i n e v e r y p a r t o f t h e r i v e r ; b u t a s t h ed i f f e r e n c e w i l l d i m i n i s h a s th e s e c t i o n i n c r e a s e s , t h e e tT ee ts w i l lo f c o u r se d i s a p p e a r i n t h e l o w e r p a r t s o f t h e ri v er . W h e no p e r a t i o n s d o t a k e p l a c e , t h e y w ill s c o u r a n d d e e p e n t h e r i v e r ,w h e r e t h e m a t t e r i s a l l u v i a l a n d l o o s e ,04, Abingdon-street, W estminster, TH OM AS TE LF O R D .June 11, 1823.I X . Observa tions on the Pro jec t o f tak ing dowu and re .b u i ld in g Lo n d o n B r id g e .
T is a m a t t e r c e r t a i n l y o f g r e a t i n t e r e s t t o m e n o f s c ie n c e , t o. _ ~ k n o w w h a t e ff ec t t h e r e m o ~ a l o f a d a m p r o d u c i n g a fifll o fw a t e r w e s t w a r d a t h i g h w a t e r s o m e t i m e s o f t w o f e et , ~ and e a s t -w a r d a t l o w w a t e r s o m e t i m e s o f n i n e f e et , fr o m a g r e a t r i v e rl ik e t h e T h a m e s , w o u l d h a v e w e s t w a r d a n d e a s tw a r d o f t h a td a m in r e s p e c t t o t h e b e d a n d s h o r e s o f su c h a r i v e r ; a n d
'~ Fro m the Qu arterly Journal o f Science, c. No . xxx.w h e t h e r
Downloadedby[UniversityofCambridge]a
t14:3804November2
013