Page:Transactions of the Geological Society, 1st series, vol. 4.djvu/66

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It may be desirable to give an estimate of the quantity of coal that is annually received from the Coal-field. The annual shipment of coal for a series of years from the Tyne, the Wear, Hartley and Blyth will be found in the appendix, No. 2. From these it appears that the quantity shipped

From the port of Newcastle, in the year 1813, was of Newcastle chaldrons^[1]	598,773
From the port of Sunderland	330,967
From Hartley and Blyth, in the year 1811.	53,958
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^[2]The quantity shipped annually from the four ports being about	983,698
The quantity vended from 35 Landsale pits in the county of Durham was in the year 1808	78,442
The quantity consumed in Newcastle, Sunderland, North and South Shields, Hartley and Blyth was computed by Dr. Macnab^[3] in the year 1801, at	190,000

But there are no precise data for calculating the home consumption of the two counties. About thirty years ago a practice was adopted at the pits, where the coal was of a fragile nature, of erecting screens to separate the small from the sounder coal. This system is now become universal, and immense heaps of coal are thus raised at the mouths of the pits. These soon take fire from the heat of the decomposing pyrites,^[4] and not less than 100,000 chaldrons are thus annually destroyed on the Tyne and nearly an equal quantity on the Wear. It is greatly to be desired that some use should be found for the small coal in order to prevent so great a waste.

↑ The New castle chaldron = 53 cwts. or $\scriptstyle {\frac {15}{8}}$ of the London chaldron.
↑ It appears from the table given in the Appendix, (No. 2.) that in the year 1813, 970,901 London chaldrons of coal were imported into London. Deducting from these the 50,000 chaldrons brought by canals from the midland counties, there will remain 920.901 London chaldrons = 491,147 Newcastle chaldrons of coal imported by sea into London.
↑ See his Tract on the Coal trade.
↑ Beneath the heaps that have taken fire, a bed of blackish brown scoria is formed, which greatly resembles basalt, and is used for mending the roads.

[1] The New castle chaldron = 53 cwts. or $\scriptstyle {\frac {15}{8}}$ of the London chaldron.

[2] It appears from the table given in the Appendix, (No. 2.) that in the year 1813, 970,901 London chaldrons of coal were imported into London. Deducting from these the 50,000 chaldrons brought by canals from the midland counties, there will remain 920.901 London chaldrons = 491,147 Newcastle chaldrons of coal imported by sea into London.

[3] See his Tract on the Coal trade.

[4] Beneath the heaps that have taken fire, a bed of blackish brown scoria is formed, which greatly resembles basalt, and is used for mending the roads.

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