NOTE ON THE TJNDERGEOUND FIEE. 275 



XVI. — Note on the Underground Fire at South Shields. By 

 Geoege Lyall, F.G.S. 



The underground fire at South Shields having attracted some 

 attention beyond the immediate neighbourhood, it was suggested 

 to me by Dr. Hooppell that a few notes on the subject might 

 not be unacceptable to the members of the Club, on the occasion 

 of their Field Meeting in this locality. The main thoroughfares 

 of Holborn and Commercial Road, between their points of junc- 

 tion at the Mill Dam and Mr. Edwards' dock, enclose an area of 

 twenty-three acres, and it is near the centre of this enclosure 

 that the fire prevails. This area contains several heaps or hills, 

 some of them, as Carpenter's hill and Johnson's hill, rise between 

 fifty and sixty feet above the street level, and have been formed 

 chiefly of the refuse materials used in the manufacture of salt 

 from sea water, for which South Shields was once famous. Up 

 the sides and on the tops of these hills, streets and houses have 

 been erected, and contain a considerable population. The earliest 

 notice of the manufacture of salt here is in 1489, when Lionel 

 Bell obtained from the Prior of Durham a lease for sixty years 

 of a parcel of land near St. Hilda's chapel, on which he con- 

 structed two iron pans. In 1667, the accounts of the chapel 

 wardens of St. Hilda show an assessment of one hundred and 

 twenty-one salt-pans. In 1696, when the salt trade had reached 

 its height, the number was one hundred and forty-three. From 

 that time, Surtees tells us, this branch of trade gradually de- 

 clined; and, in 1820, when he published his great work, only 

 five salt-pans remained. Since that time, they have entirely 

 disappeared. 



The manufacture of salt from sea water was a very simple 

 process. By the application of a slow heat, the water was 

 evaporated, and the salt precipitated and dried. When the 

 evaporation was completed, from seventy to seventy-five per cent, 

 of the residuum consisted of the chloride of sodium, or common 

 salt. The other principal and refuse solids were chloride of 

 magnesium, sulphates of magnesia, and lime, with smaller pro- 

 portions of other chlorides and carbonates, and combinations of 



