620 PHILOSOPHICAL TRANSACTIONS, [aNNO l/ll. 



A Demonstration of the Number of Acres contained in England or South Britain ; 



and the use which may be made of it. By Dr. Nehemiah Grew, F.R.S, N° 330 



p. 266. 



Several persons of respectability have given us, as they have supposed, the 

 just number of acres contained in England, or South Britain, or very near it. 

 Sir William Petty reckons about 28 millions : others, 29 millions ; others a 

 few more. But I humbly affirm, they have all under-reckoned : which seems 

 to have been owing to their reckoning only by the maps ; that is, by computed 

 and not by measured miles ; by which only the number of acres can be known. 

 I have seen an account of the number of acres in each county : which account, 

 whether taken from dooms-day book, or from any other registry, cannot be 

 true. For though we have lost some land, yet there is a great deal more now 

 gained, which in the conqueror's time lay under sea. Within 120 years, very 

 much has been recovered out of the seas, and maintained by banks, in the 

 marshes and fens of Essex, Kent, and the isle of Ely : and in some parts of 

 Lincolnshire, the land has gained of the sea, 4 miles in a direct line from land 

 to sea, in the memory of men now living. Nor is it the truer, for having been 

 taken from any other record : for if the numbers of acres, according to the 

 said account, in each shire, be put together, they exceed not 39 millions and 

 a quarter : which number, though it comes much nearer the truth than any of 

 the former, is yet a great deal short of it. For however, according to vulgar 

 computation, England be reckoned in length only 305 miles and in breadth 

 about 290 miles ; yet it appears, by an exact wheel measure, that from New- 

 haven in the south of England to London, are 56 measured miles ; and that 

 from thence by a straight line continued to Berwick in the north, are 339 of the 

 same measured miles ; in all 395 measured miles, the true length of England. 

 And again, that from the south foreland in the east, to the lands-end in Corn- 

 wall, are about 367 miles of the same wheel measure, the true breadth of England. 



This being known, it is easy, without any laborious and costly survey, to 

 know also, how many square miles, and consequently how many acres are con- 

 tained in England, or Great Britain ; viz. in the following manner. If a line 

 be drawn on a chart of England, pi. 16, fig. 12, from the south foreland in 

 Kent, to Berwick ; and from the two ends of this line, two more lines meeting 

 at the lands end in Cornwall, they will make the triangle abc ; which triangle 

 since it excludes as much more of the land, as it includes of the sea, as may an- 

 swer the small number of miles obtained by the curvity of the roads ; it may 

 therefore be allowed to be equal to the area of England. Now the length be- 

 tween Berwick and the south foreland in Kent, being about 5 miles more than 

 between Berwick and Newhaven, which is 395 miles : therefore the line ab. 



