6f>> 



ENGLAND. 



HU mis- 



*i*iet. Norwood's measure of* degree of latitude, instead of the 

 ""^ "V"^*^ true measure ; or sixty- nine miles and a half, instead of 

 - i\l\ -nine and one fifth : had he used the l.itti-r ine.i- 

 ureof a degree of latitude, the total would have been 

 I need nbout 370,000 acres, which would have nearly 

 coincided with the area of South Britain, as given by 

 Morden's map, when measured according to the true 

 length of the successive degrees of latitude and lon- 

 gitude: the single map, from which I)r Halley took 

 die gross amount, was Adam's, and the map from 

 which he took the several counties, was die six-sheet 

 map of Saxton's. 



In the Philosophical Transactions for the year 1711, 

 (No. 330, page 266.) are given the calculations of Dr 

 *>r Grew'i Nehemiah Grew on this subject, and the result of tlu>> 

 calculations. According to him, South Britain con- 

 tains 72,000 statute miles, and consequently 46,080,000 

 ctatute acres. As Dr Grew was at the trouble to ob- 

 tain a wlieel measure of those roads which were ne- 

 cessary to supply him with what he conceived to be 

 sufficient data on which to found his calculations, it 

 might be supposed that the area he assigns to South 

 Britain would approach very nearly to the truth ; but he 

 unaccountably forgot, that roads are not always straight 

 or smooth ; ;uid assuming, on the contrary, that the 

 wheel measure of them gave him a straight line, he 

 makes the length of South Britain, from Newhaven, in 

 Sussex, to Berwick, 395 miles ; and its breadth, from 

 the South Foreland of Kent to the Land's End, he 

 makes 367 miles ; both, as we shall afterwards see, con- 

 siderably above the truth. Nor was this mistake re- 

 specting the roads the only source of his error ; for he 

 very carelessly and inaccurately conjectures, that a 

 right-lined triangle, formed by uniting the South Fore- 

 land and the Land's End with Berwick, is commensu- 

 rate with the space contained by the irregular outline 

 of die country. This error would have given less than 

 the real area to South Britain, had the sides of the 

 triangle corresponded with the actual distances, though 

 the amount was not sufficient to destroy the error ari- 

 sing from making these sides too long. 



Tonple- The next calculation respecting the area of South 



man's. Britain, was given to die world by Mr Thomas Tem- 

 pleman of Bury, in his work entitled a New Survey of 

 the Glohe. According to him, it contains 49,450 square 

 miles, or 31, 648,000 statute acres. This extent, much 

 more below die truth than the calculation of Ur Grew 

 raised it above it, Mr Templeman obtained, by adopt- 

 ing a mode of computation that is progressively more 

 erroneous, as it is applied So countries more distant from 

 the equator. Mr Arthur Young seems to have been 

 the first who objected to the accuracy of Templeman's 

 calculation ; but not perceiving the source from which 

 the error of this author took its rise, he endeavours to 

 correct it on improper grounds; and supposing that 

 the error would be rectified by taking 69^ miles in- 

 stead of 60 miles to a degree, and moreover suppo- 

 sing, that Templeman erred as much in his calculation 

 respecting the area of England, as die calculation of 

 Necker respecting the area of France proved he had 

 Mr Arthur done with regard to that kingdom ; Mr Young assigns 

 Young's. to England and Wales 46,91 5,933 acres. 



Amidst this uncertainty of calculation and opinion 



on this subject, the trigonometrical survey of Englahd 



was begun ; and, in its progress, it was abundantly and 



clearly proved, that the geography of this country, in 



many respects, was very erroneous. Indeed, before it 



Error* in was commenced, it had been discovered, tli.it in the 



thcnup*. older maps the counties in die vicinity of die metro- 



polis were erroneously laid down, bodi widi respect to SouWc* 

 the general amount of their area, and widi respect to ^ "V~ " 

 the particular areas of each ; so that the distance from 

 the South Foreland in Kent, t.i the Land's End, was 

 ascertained to be less by about half a' degree than had 

 Infii formerly laid down. 



For all the purposes of political aridimetic, however, 

 it is not necessary 1 to have recourse to that minute ac- 

 curacy which trigonometrical surveys afford. A suffi- 

 cient degree of accuracy will be afforded by a mode of 

 computation, ingenious, easy, and satisfactory, which 

 was published by Ur Becke, in his Observations on the Dr Bccke't 

 Produce of the Income Tax. He was naturally led to mode of od- 

 the consideration of the subject of die extent of South c j" lad ",*. 

 Britain, by the computation of the income of Great ' 

 Britain, as stated by Mr I'itt in the House of Commons. 

 This statesman had assumed the truth of Mr Young'* 

 calculation respecting the area of England, (to which 

 Mr Middleton, in Ins Survey of Middlesex, had also 

 lent die authority of his name,) and, consequendy, had 

 rated the income of diis county, in Dr Becke's opinion, 

 much too high. Dr Becke formed a scale, which is 

 given below, the construction of which depends on the 

 length of die degrees of latitude and longitude, accord- 

 ing to their situation on die surface of the earth. In 

 this scale, die number of acres and decimal parts in 

 every successive four-sided figure, or trapezoid, are 

 given ; these trapezoids being formed by the intersec- 

 tion of lines, or circles of longitude and latitude, whose 

 distance from one another is a minute, or the sixtieth 

 part of a degree. The length of the degree of latitude 

 and longitude, according to their situation, by which 

 the following scale is calculated, is taken from die re- 

 cent observations and measurements for that purpose, 

 in this country, as they are detailed at large in die 

 Philosophical Transactions. 



A trapezoid, formed by drawing parallel lines across 

 a map from east to west, and others from south to 

 north, at die distance of the sixtieth part of a degree, 

 contains, on an average of every ten minutes succes- 

 sively, the following number of acres and decimal 

 parts. 



