HEPORT ON THE KAINFALL OF THE BEITISH ISLES....

'[From the Report of the British Association for the Advancement of Science for 1871.]

HEPORT

ON THE

KAINFALL OF THE BEITISH ISLES.

//btl

Report on the Rainfall of the British Isles, by a Committee, consisting

of C. Brooke, F.R.S. {Chairman), J. Glaisher, F.R.S., Prof.

Phillips, F.R.S., J. F. Bateman, C.E., F.R.S., B. W. Mylne,

C.E., F.R.S., T. Hawksley, C.E., Prof. J. C. Adams, F.R.S., C.

Tomlinson, F.R.S., Prof. Sylvester, F.R.S., Dr. Pole, F.R.S.,

Rogers Field, C.E., and G. J. Symons, Secretary.

Yotjr Committee have much pleasure in reporting that the organization under their supervision is believed to he in a generally efficient state. With a staff of observers, numbering nearly two thousand, spread over the whole extent of the British Isles, there can, however, be no question that, to ensure perfect efficiency and uniformity of observation, a systematic inspection of stations is absolutely necessary. In a paper read before the Society of Arts in 1858, Mr. Bailey Denton appears to have considered that there should be one inspector to about each 200 stations; at that rate we ought to have ten. The Meteorological Committee of the Royal Society have made it a rule to have all their stations inspected each year. On the most moderate com¬ putation it is indisputable that at least one inspector of stations is required for our large body of observers, the whole of whose time should be devoted to travelling.

Ever since their appointment your Committee have felt and acted upon this conviction; but want of funds has prevented them from employing a regular inspector, and obliged them to rely solely upon the unpaid services of their Secretary. Even under these adverse conditions considerable progress has been made with the work, and upwards of 400 gauges had been visited and examined previous to the Liverpool Meeting. At that Meeting, how¬ ever, the Association only granted half the sum for which we asked, and we have consequently (most reluctantly) been obliged to stop this important and useful work.

As an interim measure, and with a view to ascertaining in what districts inspection is most requisite, it has been suggested that a schedule of ques¬ tions as to the positions of their rain-gauges should be sent to every observer. The Committee unanimously approved of the suggestion, and annex a copy of the Circular and Schedule they are about to issue.

British Association Rainfall Committee, 62 Camden Square, London, N.W.

Sir,—The above Committee feel that it is most important that precise in¬ formation as to the position of all the rain-gauges in the British Isles should be promptly obtained. They are aware that under present circumstances it is impossible that each gauge should be personally inspected, and have there¬ fore instructed me to ask you to fill up the accompanying form, which I shall be obliged by your returning as soon as possible.

As an indication of the kind of information which the Committee desire to collect, I have filled up one form for my own gauge; but there are of course many subjects not touched upon in the specimen which will be ac-

ON THE RAINFALL OF THE BRITISH ISLES. 99

ceptable in others, such as distance from the sea and from lofty hills, as well as their direction, <fcc.

The Committee will also he glad of any suggestions as to the conduct of rainfall work, and of information respecting any stations or old observations not included in the list published by them in 1866, and of which I shall be happy to send you a copy if you have not already received one.

Yours very truly, G. J. Symons, Secretary.

[Illustration of mode of filling up return.]

POSITION AND PAETICULAES OP THE RAIN-GAUGE At [Camden Square, London,] In the County of [Middlesex.]

Year in which observations were first made [1858.] Hour of observation [9 a.m.] If entered against the day of observation, or

the one preceding [Preceding]. Position [In garden, 120 ft. by 24 ft.] Surrounding objects, their distances and heights:—

Distance. Height. N. [WaU .. 17 ft. .. 5 ft.] N.E. [House .. 92 ft. .. 40 ft.] •E. [Wall .. 15 ft. .. 5 ft.] S.E. [Wall .. 12 ft. .. 5 ft.] S. [Wall .. 16 ft. .. 5 ft.] S.W. [Summer House .. 24 ft. .. 7 ft.] W. [Raspberry-bushes .. 6 ft. .. 3 ft.] N.W. [Wall .. 12 ft. .. 5 ft.]

Inclination of ground [Quite level, but in N.E. rises 30 ft. in | mile.] Height of Ground above sea-level [111] ft. as determined by [Levelling from

Ordnance Bench-mark]. Height of top of gauge above ground [0] ft. [6] in. Pattern of gauge. (If similar to any on plate, quote the number ; if not,

give sketch.) [Similar to No. X., but the bent tube is made straight, and a jar inserted for the purpose of ensuring more accurate mea¬ surement.]

Have the same gauge and measuring-glass been used throughout ? [No.] Has the gauge always been in the same position ? [No.]

f the previous position [300 yards further west.] If not, state briefly < the reason for the alteration [Growth of trees.]

[ the supposed effect [None perceptible.]

Remarks. [Measuring-glass broken in 1861, and a new tested one obtained, the

rainfall of each day until its arrival being bottled separately, and mea¬ sured by the new glass.] Signed, [G. J. SYM0NS.] Another branch of investigation which has been arrested by the same

cause is the relative amount of rain falling in different months, or, as we have usually termed it, the 44 monthly percentage of mean annual rainfall." Several articles upon the subject have appeared in our previous Reports; and last year we pointed out that the observations for the decade 1860-69 offered data of completeness unparalleled, either in this or any other country, the

hJ2

100 REPORT 1871.

result of which we had hoped to have submitted to the present Meeting. Excepting in our own Eeports, we are not aware that the seasonal distribu¬ tion of rain in this country has received any attention, while on the Con¬ tinent it has at all times been looked upon as almost equally important with the gross amount.

Although several short and interrupted sets of observations have been made in Northern Derbyshire, the rainfall of that hilly district has not hitherto been examined with the thoroughness which its importance deserves. "We have in previous Eeports urged the desirability of several additional stations being established; and as no one else undertook the work our Secre¬ tary did so, and by the assistance of the observer at Euxton, and Mr. Hazlewood, of Castleton, was enabled to commence several sets of rain- gauge observations in the district. Some others are still required, which, if our funds permit, we intend to add.

Pit-gauges.—In our last Eeport we drew attention to the fact that a gauge of which the orifice was horizontal, level with the ground, but in a small pit or excavation, had at Calne collected about 5 per cent, more than one of which the receiving surface was one foot above the ground; whence it followed that as a great many rain-gauges (the majority in fact) are placed with their apertures a foot above the surface, the records of all these gauges were below what they would have been if placed in pits as just described. We gave some reasons which appeared to us to prevent the general use of pit- gauges, and added the following concluding remark on page 176 :—

"This result appears so startling that further experiments will be*con¬ ducted on the subject."

The funds at our disposal have not allowed us to do so; but fortunately the Eev. E. W. Stow, M.A., has tried one pair of gauges mounted in this manner at Hawsker, on the Yorkshire coast, a few miles south of Whitby. The following are the results during 1870:—

Table I.—Êxperiments with Pit-gauges.

Hawsker, 1870. Brit.Assoc.Beport, 1869-70.

Months. 5-in. gauge at 1 foot.

5-in. gauge in pit. Eatio. Calne, 1866-7,

mean ratio. Difference.

January .... 1*610 1*770 110 113 3 Eebruary.... 1*995 2*300 115 109 + 6 March 1*052 1*293 123 107 +10 April 0*370 0*390 105 105 0 May .... .... . . . June 2*650 2*705 102 102 0 July 0*920 0*977 106 103 + 3 August .... 1*887 1*908 101 103 — 2 September .. 0*845 0*934 110 103 + 7 October .... 5*000 5*053 101 102 — 1 November .. 3*043 3*234 106 106 0 December . . 5*230 6*420 123 108 + 15

Totals 24*602 26*984

Means 109-3 ' 105*5 + 3*8


Of course it was not to be expected tbat tbe results of a single year should agree exactly with the mean of two other years, still less when the size of gauge used was different, and the locality so opposite as the inland district of Calne and the rock-hound Yorkshire coast. We therefore look upon it as satisfactory that in only four months out of eleven do the ratios at Calne and Hawsker differ more than 3 per cent. In April, June, and November they are identical. The Calne results are thus strongly confirmed; and it may be considered as certain that pit-gauges always exceed those at one foot, although the precise amount of excess remains to be determined.

In our last Eeport we expressed the hope that we should this year be able to state the result of the discussion of all the rainfall registers which were absolutely continuous from January 1, 1860, to December 31, 1869. We have the pleasure of doing so in two respects, viz. (1) with reference to their bearing on the question of the existence or otherwise of secular variation of rainfall in the British Isles, and (2) as data indicative of the distribution of rain over the country.

The secular variation of rainfall, or the relative dryness and wetness of different years and groups of years, is one of the most important and difficult branches of rainfall work. It has been treated in our Reports for 1865, and very fully in that (or 1866. In the latter we gave the calculations in detail, from which the values shown on the accompanying diagram were obtained. Referring to that Report for full explanation, we have only now to mention that the subsequent years 1866 to 1869 have been computed in the same manner and added to the diagram (fig. 1). We may also remark that various observations collected since its publication have confirmed the general accuracy of the curve quite as much as could have been anticipated. On the present occasion we do not intend to discuss the relative rainfall of different years, but the relation of the fall during the ten years 1860-69 to previous decades. For this purpose we have grouped the yearly values in decennial periods, similar to those adopted in our 1867 Report, whence we obtain the following result:—>

Table II.—Ratio of Rainfall in each ten years since 1730 to the Mean of sixty Years, 1810-69.

Period. Ratio. Period. Ratio. 1730-39 89-9 1800-09 88-2 1740-49 70-6 1810-19 98-6 1750-59 85-5 1820-29 103-2 1760-69 91-1 1830-39 101-4 1770-79 103-5 1840-49 102-6 1780-89 93-5 1850-59 95-2 1790-99 96-5 1860-69 101-5

Having previously pointed out the peculiarities of the earlier portion of the curve, it is only necessary on the present occasion to call attention to the last forty years, whence it will be seen that, according to this mode of inves¬ tigation (which is principally based on English returns), three out of the four decades had a rainfall nearly identical, and the other (1850-59) considerably below them, the deficiency being nearly 7 per cent.

This result is based on a combination of records, as fully explained in our 1866 Report. We proceed to examine how far it is corroborated by individual stations, but are at once confronted by the paucity of stations of which per¬ fectly continuous records for even half a century exist. We therefore con¬ fine ourselves to the forty years, from 1830 to 1869, for which period we

102 REPORT 18ri.

jo ûao


have twelve perfect records at widely separated stations. The mean fall in each decade and in the whole period, and the ratio of each decade to the whole period at each station, is given in Table III.

Fig. 2. CNCNCNONONONCTSCNCNCNONOSONON I I I I I I I \ I i I I I \ oooooooooooooo CO TJ- to VOt-sOO ONO t^r^t^-tôooooooooooooo

From careful examination of Table III., it appears that the amount of rain which fell in the ten years 1830-39 was very similar to that which fell in the ten following years, the difference being a decrease, but scarcely one per cent. The investigation in our 1866 Report shows an increase of 1*2 per cent.; and examination of returns ceasing in 1850, and therefore not quoted in either Report, show several cases of absolute identity.

With one investigation leading to a decrease of 1 per cent., another to an increase of the same amount, and a third to identity, we are led to the con¬ clusion that the two decades may be considered to show similar results. This is a much more important fact than it at first appears; and for this

Table III.—Comparison of the Rainfall in each Decade since 1829 with the Mean Rainfall of forty years, ending with 1869.

Station. Mean Rainfall in each 10 years. Mean

Rainfall, 1830-69. 1830-39. 1840-49. 1850-59. 1860-69.

Epping Exeter Institution Tavistock Halifax Kendal Point of Ayre.... Rhinns of Islay .. Isle of May Buchanness Kinnairdhead Island Glass .... Start Point

in. 25-84 28-92 52-81 34-51 56-22 28-26 34-07 21-96 26-40 19-66 33-23 27-39

in. 26-99 29-35 54-27 31-88 51-18 28-20 33-79 20-94 26-84 22-01 34-98 25-05

in. 23-18 26-91 49-18 30-71 44-91 29-01 30-58 15-21 23-40 22-05 31-92 23-77

in. 24-13 31-76 53-17 33-31 53-32 30-61 33-43 20-48 25-59 24-17 31-13 31-37

in. 25-04 29-24 52-36 32-60 51-41 29-02 32-97 19-65 25-56 21-97 32-81 26-89

Means 32-44 32-12 29-24 32-71 31-63

Ratio of Means . . 102-6 101-6 92-5 103-4

104 REPORT—1871.

Table III. (continued).

Ratio of Rainfall in each 10 years' to 40 Station. years' Mean.

1830-39. 1840-49. 1850-59. 1 1860-69.

Epping 103 108 93 96 Exeter Institution 99 100 92 109 Tavistock 101 104 94 101 Halifax 106 98 94 102 Kendal 109 100 87 104 Point of Ayre. . . . 97 97 100 106 Ithinns of Islay . . 103 102 93 102 Isle of Hay .... 112 107 78 103 Buchanness 103 105 92 100 Kinnairdhead.... 90 100 100 110 Island Glass 101 107 97 95 Start Point 102 93 88 117

Mean Ratios . . . . 102-2 101-8 92-3 103-7

reason : while there are only about a dozen registers complete for the four decades, there are thirty-eight which are complete for the last three decades. How that we have found the relation between the first two decades, the re¬ turns for the thirty years are rendered almost as instructive as those for forty years.

Fig. 3.

186G Report. 1871 Report. All stations.

nc

9°

"We have therefore compiled Table IV., which differs from Table III. only in its being for thirty years instead of forty, and in giving observations from thirty-eight stations instead of twelve.


Table IY.—Oomparison of the Rainfall in each Decade since 1839 with the mean Rainfall of thirty years ending 1869.

Division. County. Station. Mean Rainfall in each

10 years. Mean Rain¬ fall.

Ratio of Rainfall in each decade to 30

years Mean.

1840-49. 1850-59. 1860-69. 1810-69. 1810-19. 1850-59. 1860-69.

II. »

III. IV.

19 V. a a a

VI. VII. VIII. IX.

it a

X.

xi. XII. XIII.

*t XV.

tt it

XVI.

XVII. it

XVIII. >>

XIX. >> it

XXI. XXIII.

Sussex it

Herts Essex Norfolk Wilts Devon

it tt

Worcester ... Nottingham... Lancashire ... Yorkshire ...

,, a tt

Durham Westmoreland Isle of Man ... Wigtown Haddington... Edinburgh ... Bute Argyll

Fife Perth Kincardine ... Aberdeen

» Ross

tt Sutherland ... Caithness Orkney Shetland Dublin Antrim

Chichester Infirmary ... „ (Chilgrove)...

Hemel Hempstead Epping Diss (Dickleburgh) Salisbury (Baverstock) Tavistock (West St.) ... Exeter Institution Honiton(Broa dhembury ) Tenbury (Orleton) Welbeck Bolton (The Folds) Redmires Halifax (Well Head) ... Settle York Bishopwearmouth Kendal Point of Ayre Mull of Galloway, L.H. Haddington Inveresk Pladda L.H Mull of Cantire, L.H. Rhinns of Islay, L.H. Isle of May, L.H Deanston Girdleness, L.H Buchanness, L.H Kinnairdhead, L.H. ... Island Glass, L.H. .;.... Barrahead, L.H Cape Wrath, L.H. ...... Dunnethead, L.H Start Point, L.H Sumburghhead, L.H. ... Black Rock Belfast Linen Hall

in. 29*10 33'4i 25*86 26*99 25*05 31*09 54*27 29'35 SS'H 28*41 25*44 46*46 4o*75 31*88 43*4i 25*42 19*94 51*18 28*20 20*67 23*77 25*81 40*02 4576 3379 20*94 35*74 23*14 26*84 22*01 34*98 31*60 38*86 27*39 25*05 25*43 23*20 29*44

in. 26*67 32*23 26*43 23*18 22*31 28*69 49*i8 26*91 32*75 28*82 23*29 44*oi 37-86 3071 SB'S' 22*02 l6*9I 44*91

29*01 22*52 24*35 24*72 35*23 41*19 30*58 15-21 39*21 1971 23*40 22*05 31-92 32*67 36-94 22*09 23*77 25*22 21*78 30*01

in. 29*03 33*22 26*39 24*13 22*22 30*25 53*17 31*76 34'56 30*90 24*64 48*98 39-68 33'3I

4I'3S 24-48 20*25 53*32 30*6l 2766 25-63 29*02 40*I4 44*17 33*43 20*48 43*99 22*72 25*59 24*17

31*73 39*37 25*40 3i*37 26-45 27*10 3677

in. 28*27 32*95 26*23 24*77 23*I9 30*01 52*21 29*34 34'15 29-38 24*46 46*48 39*43 3i*97 40*09 23*97 19*03 49*80 29*27 23*62 24-58 26*52 38-46 4371 32*60 i8*88 39'®5 21*86

* 25*28 22*74 32*68 32*00 38-39 24*96 2673 25*70 24*03 32-07

103 101 99

109 108 104 104 100 103 97

104 100 103 100 108 106 105 103 96 88 97 97

104 " io5

104 in 9°

106 106

97 107 99

101 no 94

96 92

94 98

101 9£ 96 94 92 96 98 95 95 96 96 89 92 89 90 99 95 99 93 92 94 94 81 99 90 93 97 98

102 96 88 89 #

98 91 94

103 101 100 97 96

100 102 108 101 105 IOI 105 101 104 103 102 106 107 105 117 104 110 104 IOI IQ2 108 111 IO4 101 106 95 99

103 102 117 103 113 114

Abstract of Table IY.

England and Wales, 19 stations Scotland, 17 stations Ireland, 2 stations

33*23 29*52 26*32

30*60 27*69 25*90

33-28 3073 3I-93

32-37 29*3I

28*05

102*8 100*9 94*o

94*7 94*o 92*5

1027 105*1

."3*5 Mean of the above Mean of 38 stations

29*69 31*21

28*06 29*05 31-98

32-07 29*91 3078

99*2 101*5

937 94*3

107*0 104*2

From the above Table the remarkable similarity of the results obtained by the two dissimilar modes of investigation is rendered so obvious that it

106 REPORT 1871.

is unnecessary to dwell further upon it. IVe now proceed to the second part of our investigation, namely, to consider the distribution of the rain¬ fall of the last decade, during which we have nearly four hundred perfect sets of observations. As each set of observations comprises more than a thousand entries, and the following Table contains the result of nearly half a million observations, it is probable that it contains some slight percentage of error, but we have no suspicion of the existence of any which appreciably affect the results.

The head-lines of the following Table sufficiently explain its contents.

Table Y.—Mean Rainfall at 325 Stations during the ten years 1860-69.

County.

Division I.

Middlesex ..

Division II.

Surrey >9 99 99

Kent 99 99 * 99 ......

Sussex 99 99 * 99 '99 •9 99 99 99

Hampshire ..

Berkshire ... 99 • ' •

Division III.

Herts

Height of Rain-gauge. Mean Station. Above Above sea.

Annual Rainfall,

ground. 1860-69.

ft. in. feet. inches.

Camden Town 0 6 100 25-681

Weybridge Heath 0 6 150 25-051 Croydon (Tanfield Lodge) .. 0 8 155 26-333

,, (Waldronhurst).. .. 35 0 237 24-388 Wimbledon 3 0 160 23-476 Kew Observatory 1 3 19 23-282 Hythe (Horton Park) 1 4 350 32-677 Tunbridge 1 0 71 28-258 Maidstone (Linton Park) .. 0 6 296 27-559

,, (Hunton Court) .. 0 6 80 25-998 West Thorney [Emsworth].. 0 8 10? 26-875 Chichester Museum 0 6 50 29-026

„ (Shopwyke) 1 2 61 29-194 ,, (West Dean) .... 1 6 250 37-082 „ (Chilgrove) 0 6 284 33-224

Arundel fDale Park) 3 5 316 33-732 Hastings (High Wickham).. 2 0 212 26-373 Maresfield Rectory 1 3 250 32-199

„ (Forest Lodge) .. 1 2 259 31-479 Isle of Wight (Osborne) 0 8 172 30-725 Fareham (Horth Brook).... 0 2 26? 33-906 Petersfield (Liss) 0 7 .... 38-033 Selborne (The Wakes) .... 4 0 400 34-427 Aldershot 3 0 325 27-036 Reading (Englefield) 1 0 190 25-726 Long Wittenham 1 0 170 27-379

Bayfordbury 0 4 250 25-011 St. Albans (Gorhambury) .. 2 9 27-849


Table V. (continued).

County. Station.

Height of Hain-gauge.

Above ground. Above sea.

Mean Annual Rainfall, 1860-69.

Division III (continued).

Herts

>> * Bucks Oxford

Northampton >>

Hunts Bedford .. ..

,, . . . . ,, ^ . . . .

Cambridge ..

Division IY,

Essex >? >)

*

Suffolk*.* „ . . . . ,, . . . . ,, . . . .

Norfolk .. .. j> • • • • ,, . . . . ,, . . . . a > • • • >> . . . . » • • •« ,, . . . . >> . . . . » .. ..

Division Y.

AViltshire.. .,

HemelHempstead(NashMills) Tring (Cowroast) Hitchiu Royston High Wycomb Radcliffe Observatory.... Banbury (High Street) .. A1 thorp House Wellingborough Kimbolton (Hamerton) .. Cardington

Ely (Stretham) Wish each (Harecroft House)

Epping AYitham (Dorward Hall) .. Dunmow Braintree (Booking) Saffron Walden (Ashdon) .. Hadleigh (Aldham) Bury St. Ed. (Abbeygate) ..

„ (Westley) „ (Barton Hall) „ (Culford)

Diss (Dickleburgh) Downham Market (Outwell)

„ „ (Eincham) .. Norwich Institution

„ (Cossey) ,, (Honingham Hall)

Fakenham (Egmere) Holkham

>> Hunstanton

Baverstock Salisbury Plain (Chiltern Ho.) Swindon (Penhill) ......

ft.

3 4 1 0

0 2 4 6

0 9 0 8

0 4 3 4

0 0 3 6

36 0 4 9 0 8

6 0 1 6 0 0 3 6 1 2

35 0 1 1 1 3 4 4

30 0 1 0 4 0 0 4 0 3 8

3 0 4 0 0 10

feet.

250 395 238 266 225 207 350 310

170 106 109 142

"ii

360 20?

234 200 300

"240? 216? 145? 84?

120 16

100 53

150 39 43 60

300 380?

inches.

26-388 27-594 23-922 23-569 25-705 26-129 26-222 23-349 24-092 23-132 22-487 21-760 18-170 20-609 24-037

24-132 20-466 22-750 23-984 23-056 25-469 23-962 23-522 23-680 24-835 22-223 22-637 23-139 22-169 24-035 23-975 25-097 23-875 23-232 19-559

30-247 29-279 28-592

108 REPORT 1871.

Table Y. (continued).

County. Station.

Height of Rain-gauge. Mean Annual Rainfall, 1860-69.



Bridport 0 8 60 32-248 Plymouth (Saltram) 0 3 96 44-813

„ (Ham) 3 0 94 42-888 Plympton StMary(Bidgeway ) 0 6 116 48-646 Tavistock (Library) 20 0 283 43-356

„ (West Street).... 4 6 286 53-170 Bovey Tracey 0 6 92 43-126 Coryton Lew Down 6 0 445 45-941 Exeter Institution 13 7 155 31-757 Cullompton (Clyst Hydon).. 1 0 200 32-694

„ (Bradninch) 1 6 234 38-060 Honiton (Broadhembury) .. 1 6 400 34-562 South Holton (Castle Hill).. 3 5 200 47*118 Barnstaple 0 6 43 39-905

rHelstone 5 0 116 37-872 Penzance 3 0 94 41-507 Bedruth (Tehidy Park) .... 0 6 160 41-229 Truro (Boyal Institution) .. 40 0 56 42-877

„ (Penarth) 1 0 190 42-556 Bodmin (Castle Street) .... 2 6 338 47-708

„ (Warleggan) 2 6 550 54-557 Wadebridge(Treharrock Ho.) 2 9 303 39-301 Langport (Long Sutton).... 0 10 50 28-574 E. Harptree (Sherborne Bes.) 1 0 338 42-097

Bristol (Small Street) 25 0 40 30-549 „ (Phil. Inst.) 56 0 32-955

Clifton (South Parade) .... 0 6 192 34-085 Gloucester (Quedgeley) .... 0 10 50 27-421 Cirencester (Further Barton) 1 2 420 32-612 Boss (Archenfield) 1 0 250? 28-211

„ (Bocklands) 1 10 150 33-591 Leominster (West Lodge) . . 1 0 250 27-105 Burford [Tenbury] 0 11 100? 26-744 Ludlow (Knowbury) 0 4 1000? 28-530 Shiffnal (Haughton Hall) . . 3 5 355 24-870 Shrewsbury 4 4 192 19-499 Oswestry (Hengoed) 6 0 470 35-647 North wick Park 1 6 .... 28-017 Worcester (Lark Hill) 1 0 137 28-039 Tenbury (Orleton) 0 9 200? 30-900 Birmingham (Edgbaston) . . 1 3 510 30-562

Division Y. (continued).

Dorset. Devon

Cornwall

Somerset ,

Division YI.

Gloucester ...

Hereford .

Shropshire

Worcester

Warwick.

OX THE RAINFALL OF THE BRITISH ISLES. 109


Station.




Wigston 0 6 220 25-165 Thornton Reservoir 2 8 420 25-611 IValtham Rectory 1 0 560 24-319 Belvoir Castle 1 0 237 24-476 Grantham 0 6 179 22-407 Lincoln 3 6 26 20-870 Market Rasen 3 6 100 23-429 Gainsborough 3 6 76 21-659 Stockwith 3 6 21 21-347 Brigg 3 6 16 24-118 Grimsby 15 0 42 21-391 Barnetby 3 6 51 22-163 Brigg (Appleby Yic.) 0 9 60 24-097 New Holland 3 6 18 22-665 Southwell 1 0 200? 20-844 AYelbeck Abbey 4 0 80 24-636 AYorksop 3 6 127 22-469 Retford 3 6 52 22-743 Derby 6 0 180 26-807 Chesterfield 3 6 248 26-930 Kilnarsh (Norwood) 3 6 238 24-591 Combs Moss 3 6 1669 49-620

„ Reservoir 3 6 710 50-008 Chapel-en-le-Erith 3 6 965 41-947 Woodhead 3 6 878 52-188

Bosley Minns 3 6 1210 32-849 „ Reservoir 3 6 590 32-043

Macclesfield 3 6 539 34-536 „ (Park Green) .. 2 1 450 36-746

Bollington (Spond's Hill) .. 3 6 1279 37-464 Whaley 3 6 602 43-894 Marple Aqueduct 3 6 321 34-810

„ Top Lock 3 6 543 35-254 Godley Reservoir .... 500 33-979 Mottram (Matley's Eield) .. 3 6 399 37-732 Newton 3 6 396 31-633 Arnfield Reservoir .... 575 37-232 Rhodes IVood Reservoir.. .. 1 0 520 46-323 \Yoodhead „ .... 0 10 680 51-828 Denton „ .... .... 324 32-974 Gorton „ .... — 263 33-712

County.

Division YII.

Leicestershire .

Lincoln

Nottingham

Derby

Division YIII.

Cheshire

Lancashire

110 REPORT 1871.


County. Station.



ft. in. feet. inches. Division YIII.

(continued).

Lancashire .... Manchester (Old Trafford).. 2 7 106 34-727 j, .... „ (Ardwick) .... 3 0 154? 32-597 99 .... „ (Piccadilly) .... 40 0 194 36-775 99 .... Eairfield 6 0 312 40-898 „ .... Oldham (Waterhouses) .... 3 6 345 36-133 99 .... „ (Gas-works) 6 0 600 37-123 » .... „ (Strines Dale) .... 6 0 800 36-007 ,, .... Bolton (The Eolds) 3 6 283 48-981 99 .... „ (Belmont) 0 0 800 56-610

.... „ (Heaton) 0 0 500 44-210 99 .... Eochdale (Xagden Dane) .. 1 6 900 44-132 » .... Ormskirk (Eufford) 0 8 38 34-999 „ .... Preston (Howick) 0 6 73 38-303 99 .... Blackpool (South shore).... 1 8 29 32-994 ,, .... Stonyhnrst 0 8 376 48-560 99 .... Clitheroe (Downham Hall) .. 1 6 464 44-786 ,, .... Lancaster (Caton) 1 6 120 43-944 ,, .... Cartmel (Holker) 4 8 155 45-625

Division IX.

Yorkshire, W. E. Sheffield (Broomhall Park).. 2 0 340 31-276 99 Eedmires 4 0 1100 39-684 99 Sheffield Station 3 6 188 28-159 99 Tickhill 2 0 61 23-990 99 Dunford Bridge 3 6 954 56-177 99 Saddleworth Station 5 0 640 41-968 99 Standedge 2 0 1150 53-700 99 Hnddersfield (Longwood) .. 4 6 650 34-008 99 „ (Eastrick) .... 1 3 410 32-121 99 Halifax (Warley Moor) .... 1425 46-330 99 „ (Well Head) .... 0 11 487 33-313 99 „ (Midgeley Moor) .. .... 1350 50-000 99 „ (Ovenden Moor) .. .... 1375 46-090 99 Leeds (Leventhorpe Hall) .. 2 0 90 23-261 99 „ (Holbeck) 32 0 127 22-853 99 York (Bootham) 0 6 50 24-479 99 Settle 40 0 498 41-349 99 Arncliffe 2 9 750 60-075 „ E. E. Hull (Beverley Eoad) 3 10 11 25-024 „ X. E. Malton 1 0 75 27-455 99 Eichmond (Aske) 2 8 550 31-105

ON THE RAINFALL OF THE BRITISH ISLES. Ill


Countj. Station.

Height of Rain-gauge.

Aboye ground. Above sea.

Mean Annual

Rainfall, 1860-69.

Division X. Durham N orthumberland

Cumberland

Westmoreland.

Division XI.

Glamorgan .. . Cardigan Brecknock ... Radnor Plint

Denbigh Isle of Man.. Guernsey .. Alderney

Division XII.

Wigton

Kirkcudbright.

Dumfries

Bishopwearmouth Allenheads Shotley Hall By well Wylam Hall North Shields (Wallsend) „ (Rosella Place)

Stamfordham Hexham (Parkend) Lilburn Tower Seathwaite Ullswater (Watermillock) .. Bassenthwaite (Mirehouse).. Cockermouth (Whinfell Hall) Carlisle (Bunker's Hill) .. Kendal (Kent Terrace) .. Windermere (The Howe) Appleby

ft. in.

6' 9 0 3 0 6 0 4 0 6

0 0 4 0 0 6 7 0 0 6 2 0

WALES AND THE ISLANDS.

SCOTLAND.

Roxburgh

Mull of Galloway Stranraer (South Cairn).. Corsewall Little Ross Cargen [Dumfries] Dumfries (March Hill Cott.) Westerkirk (Carlesgill) .. Wanlockhead Kelso (Springwood Park)

feet.

1369 312

87 96

100 124 400 276 300 422 720 310 265 184 146 470 442

inches.

20-247 51-160 28-494 28-874 26-900 26-640 26-065 27-637 33-550 28-657

154-046 59-910 53-756 57-366 27-616 53-322 87*923 35-994

Cardiff (Ely) 3 0 45 42-016 Lampeter 4 6 420 45-183 Hay (Pen-y-maes) 1 0 317 31-680 Rhayader (Cefnfaes) 2 0 880 44-980 Hawarden [Chester] 0 7 270 26-443 Holy well (Maes-y-dre) .... 5 0 400 24-430 Llandudno (Warwick House) 0 6 99 31-004 Point of Ayre 3 4 27? 30-609

12 0 204 37-177 Harbour Works 10 0 48 28-624

27-656 i"4 209 49-603 .... .... 37-027 3 3 130? 26-981 0 4 80 44-372 0 5 70 37-045 .... .... 60-092 0 4 1330 66-628 1 o 130 24-663

112 REPORT 1871.


Station.




Bowhill 11 0 537 33-033 Penicuick (X. Esk Reservoir) 0 6 1150 38-014 Lauder (Thirlestane Castle)... Dunse (Mungo's "Walls) ....

0 3 558 29-977 0 6 267 28-494

Prestonkirk (Smeaton) .... 13 0 100 23-263 Haddington (Millfield) .... 4 0 140 25-630 East Linton 0 3 90 23-767 Cobbinsbaw Reservoir .... 0 7 863 37-450 Inveresk 2 0 90 29-016

Hamilton (Auchinraith).... 4 9 150 31-951 „ (Bothwell Castle).. 18 0 146 28-885

Glasgow (Cessnock Park) .. 4 4 29 37-958 „ (Observatory) .... 0 1 180 44-411

Baillieston 0 3 230 46-471 Shotts (Hillend House) .... 7 0 620 33-445 Ayr (Auchendrane House).. 2 3 96 44-825 Largs (Mansfield) 0 6 30 48-920 Gorbals, W. W. (Ryat Lynn) 0 5 310 47*801

„ (Waulk Glen) 0 5 280 49-845 „ (Middle ton)... 0 5 550 56-682

Meams (Nether Place) .... 0 6 360 50-143 Greenock (Hamilton Street) 0 6 50 66-156

Loch Long (Arddaroch) .... 0 10 80 78-321 Ealkirk (Kerse) 1 0 .... 32-960 Stirling (Polmaise Gardens) 0 2 12 41-300 Pladda 3 3 55 40-141 Castle Toward 4 0 65 54-554 Lochgilphead (Callton Mor).. 4 6 65 54-253 Inverary Castle 0 1 30 67-370 Appin (Airds) 0 3 15 63-640 Ardnamurchan 3 6 82? 45-594 Cantire, Mull of .. ,. 279? 44-166 Campbeltown (Devaar) .... 3 4 75? 47-312 Rhinns of Islay 3 0 74? 33-434 Lismore (Mousedale) 3 4 37? 46-215 Mull, Sound of 0 6 12? 72-159 Tyree (Hynish) 79-992

County.

Division XIII.

Selkirk . Peebles . Berwick .

Haddington

Edinburgh

Division XIY

Lanark a a • • • * ■ a a a

Ayr if

Renfrew a a ...... a

Division XY.

Dumbarton .. . Stirling

Bute Argyll it a a a ....... a a a a • * a ....... a .......



County. Station.

Height of Rain-gauge.


Mean Annual Rainfall, 1860-69.

Division XYI. Kinross Pife

Perth » 99 99 99 99 99 99 99 99 ........

Forfar 99 99 99 • ' 99

Division XYII.

Kincardine 99 • • . .

Aberdeen

Banff

Division XYIII.

Boss & Cromarty 99 99 99

Inverness ..

Lochleven Sluice Balfour Leven (Xookton) Isle of May Aberfoyle Dunblane (Kippenross) Deanston House Lanrick Castle Bridge of Turk Auchterarder House

„ (Trinity Gask) Loch Earnhead (Stronvar) . . Perth Academy Scone Palace Barry Craigton Kettins Hill Head Arbroath

Brechin (The Burn) Girdleness Braemar Aberdeen (Bose Street) Alford (Castle He we) Kinnaird Head Buchanness Gordon Castle

Isle of Lewis (Stornoway) „ (Bernera) ..

Cromarty Isle of Skye (Oronsay) ..

„ (Kyleakin) .. „ (Baasay) „ (Portree)

Barrahead S. Hist (Ushenish) Harris (Island Glass) Bona Culloden House

ft. in.

0 10 0 6

64 2 0 0 1 0 2

0 6 0 4 0 4 0 0 0 6 2 3 0 1

0 6 4. 7 1 0

3 4

1 6

3 0 3 0 6 0 2 1 4 1 8 3 0 0 4 3 4 0 6 3 0

feet.

'i27 80

182 60

100 130

270 162 133

"83 80 35

481 218 570

60

235 86

1114 95

'*64

"60

31? 15 28 15? 3?

80 80

640? 157? 50? 20

104

inches.

35-780 28-589 28-988 20-482 61-820 36-165 43-991 48-805 61-890 34-315 35-324 82-434 23-584 29-182 29-729 34-876 33-172 35-187 29-050

34-910 22-718 33-404 29-433 33-500 24-168 25-588 29-192

51-792 68-027 25-941 72-359 82-067 77-120

104-261 31-726 43-905 31-129 39-470 27-084

1871.

114 REPORT 1871.


County.

Division XIX.

Sutherland .. . j, ...

Caithness

?? Orkney

»

a

Shetland

Division XX.

Cork

Waterford .... Clare

Division XXT.

Queen's County.. King's County. . Wicklow Dublin

Division XXII.

Fermanagh Armagh Antrim

Station.

Height of Bain-gauge. Mean Annual

Rainfall, 1860-69.



Golspie (Dunrobin Castle) .. 0 3 6 27*692 Cape Wrath 3 6 355? 39-371 Wick (Xosshead) 3 4 127? 24-699 Dunnethead 3 6 300? 25-401 Pentland Skerries 3 3 72? 28-763 Hoy (Graemsay East) .... 3 4 27? 39-007

„ ( „ "West) .... 37? 32-693 Shapinsay (Balfour Castle).. 0 6 50 32-408 Pomona (Sandwick) 2 0 78 38-853 Sanda (Start Point) 0 6 29? 31-371 Horth Bonaldshay 3 4 21? 31-015 Sumburghead 3 4 265? 26-454 Bressay Lighthouse 0 4 60 36-488

IKELAHD.

Cork (Royal Institution) .. 50 0 70 34-771 Fermoy .... 37-207 Waterford (Xewtown) .... 4 0 *60 40-669 Killaloo 5 0 123 47-654

Portarlington 1 2 240 36-857 Tullamore 3 0 235 27-938 Bray (Fassaroe) 5 0 250 41-822 Black Bock (Rockville) .... 29 0 90 27-096

Enniskillen (Florence Court) 11 0 300 44-368 Armagh Observatory 1 5 208 32-014 Belfast (Queen's College) .. 7 4 68 34-225

,, (Linen Hall) 4 0 12 36-767

Before accepting these decennial averages (1860-69) as data indicative of the distribution of rain over the country, we have to offer a few prefatory remarks. The difference between the amount collected by any two rain- gauges depends on at least four separate and distinct conditions, three of which must be ascertained and corrected for before the fourth can be accu¬ rately determined.

The conditions are:—(1) length of series of observations; (2) correction for secular change ; (3) height of gauges above ground.

(1) Even if there were no other evidence in existence than the accompany-


ing diagram (fig. 1) of the fluctuations of rainfall, we feel that it would suffi¬ ciently prove the impossibility of determining accurately the rainfall at any place except by observations continued over a long series of years ^ at that place, or by differentiation from some proximate long-continued series.

(2) It does not follow that simultaneous observations, even for ten years, giving for example a mean difference between two stations of five inches, prove that the rainfall at the one station is greater than the other by that amount, although if they are not very distant the one from the other it would probably be a safe assumption.

(3) Before mean results can be given with any pretensions to accuracy and finality, they must be corrected for the elevation of the rain-gauge above the ground.

The above remarks sufficiently show that the mere average of the fall of rain measured during ten or more years does not necessarily give the true mean rainfall at that place.

Let us take as an example the highest amount recorded in the Table (Seathwaite), which had during the ten years (1860-69) an average of 154 inches; many persons would say at once that that was therefore the mean rainfall at that station. It is, however, nothing like it. From Table II. and fig. 2 we see that the rainfall over England, generally, during those ten years was 1*5 per cent, above the average, upon which evidence we are bound to reduce the observed mean in that proportion, and then the average becomes 152 inches instead of 154. Even this, how¬ ever, is not correct; for we pointed out in condition (2) that the same years, or groups of years, are not similarly wet in all parts of the country. Beferring, therefore, to Table IY. we find that at the nearest station to Seathwaite, Kendal, the decade in question was 7 per cent, above the thirty- year mean; hence, on the supposition that the Kendal values are applicable to this station, we have to reduce 154 inches by 7 per cent, instead of by 1-5 per cent., and hence the probable mean comes out 141-8 inches.

Now most fortunately we can test the accuracy of this calculation in three ways.

(1) The mean fall at Seathwaite in the previous decade was 126-98 ; from the Eendal observations the fall in that decade was 10 per cent, less than

the mean; therefore ^ we find the probable mean comes

out 141-1 from this decade, and 141-8 from that of 1860-69. They thus agree within less than an inch, or one half per cent.

(2) The fall at Seathwaite has now been continuously observed for twenty-six years, viz. from 1845 to 1870 inclusive; the mean of the whole twenty-six years' observations is 140-03.

(3) This value, corrected according to the Table in our 1866 Beport, becomes 141-44, agreeing exactly with that indicated by the decades 1850-59 and 1860-69.

This example proves three points :—(1) the great degree of accuracy which is attainable by proper methods; (2) the care requisite to secure it; (3) the serious errors inseparable from the use of mere arithmetical averages without reference to secular changes.

These observations, however, must of course be taken as general results, and not be construed as having, any bearing on the relative rainfall even of proximate stations, the rainfall of which will vary considerably according to local circumstances.

Hence it will be seen that the probable average at Seathwaite is 141 inches i 2

116 REPORT 1871.

instead of 154, or 7 per cent. less. A similar, but generally less correction, may be required for other stations. The figures in Table Y. must not there¬ fore be considered as showing the mean fall at the several stations, but only as approximations generally pretty close. The data in our possession, if cor¬ rected in accordance with the method explained, would afford more accurate results, but the investigation is altogether beyond our present resources.

Large tracts of Ireland, and even of Scotland, are still without observers ; much has recently been done to remedy these deficiencies, but there are still many localities where observations are very much wanted; we shall gladly receive any offers of assistance from those who have residences or property in those parts, and our Secretary will readily advise them as to instruments.

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HEPORT ON THE KAINFALL OF THE BEITISH ISLES....

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