Of Science: A Series of Detached ESSAYS, ADDRESSES, AND REVIEWS. BY JOHN TYNDALL, F.R.S. Printed By Spottiswoode AND CO. NEW-STREET SQUARE AND PARLIAMENT STREET End of their maintenance £2,600 £115,000 Revenue £1,230,000 £9,516,000 National expenditure £1,637,000 £8,555,000 Post offices 209 21,551 Post roads (miles) 5,642 178,670 Revenue of Post-office £22,800 £1,207,000 Expenses of Post-office £22,800 £1,207,000 Expenses of Post-office £22,800 £1,207,000 Expenses of Post-office £15,650 £1,130,000 Mileage of trains is.