566 The Account of a 



Mr. Gardner, has been furnished with materials for surveying 

 the northern shore of the Thames, and the north of Kent : these 

 proved ample, as the map, thence compiled, will sufficiently de- 

 monstrate. As the Master-General issued directions, at this 

 time, to survey Essex, and parts of the adjoining counties, in the 

 same manner, and for the same purpose, as Kent has been, I was 

 obliged to suspend, for a short time, my intention of proceeding 

 with the measurement of a meridional degree, and to devise 

 the best means for carrying his Lordship's instructions into 

 execution. 



For this purpose, therefore, before any stations were chosen 

 in Essex, the county was very minutely examined ; when it ap- 

 peared, that insuperable difficulties would occur, if the survey 

 were prosecuted with the large theodolite only. The range 

 commencing at Havering Bower, and running to Gallywide 

 Common, cuts off a regular communication between the stations 

 subsequently chosen in the southern and northern parts of 

 Essex. The difficulty resulting from this circumstance, was 

 made still greater, from the want of success in our endeavours 

 to find one spot on this range, proper for a station. The eastern 

 part was, in some degree, found more favourable ; but it was dis- 

 covered that, even here, the small instrument must frequently be 

 used as a substitute for the large one. Under these disadvan- 

 tages, the survey commenced in March; the large theodolite 

 being taken to a station on Hampstead Heath. 



The base chosen for carrying on the distances towards the 

 north, was that constituted by Severndroog Tower on Shooter's 

 Hill and the new station on Hampstead Heath ; which distance, 

 although it has not, perhaps, been obtained so correctly as many 

 others, yet is determined with sufficient accuracy for the matter 



