The debits and credits of dirt

3### The debits and credits of dirt Some people know the debit side of dirt only too well; know what it costs to clean and repaint and repair the things that soot and smoke have harmed; know what smoke-aggravated fogs with their damage and delay can mean. And they know what causes all this, too: burning coal 'raw', in fires and furnaces. But some of these people also realise that there's a creditable way to get heat out of coal, without wasting a scrap of it. It's Mr. Therm's burn to make Britain rich ' says Mr.