Water alone brought into sudden contact with red hot iron is capable of giving rise to a gas of the most destructive nature—­witness the extraordinary explosions that are continually taking place in steam-vessels, especially in America, which mostly arise from the lurching of the vessel when waiting for passengers, causing the water to withdraw from one side of the boiler, which rapidly becomes red hot.  The next lurch in an opposite direction precipitates the water upon the highly-heated surface, and thus explosive gas, in addition to the steam, is generated faster than the safety-valves can get rid of it.

A very interesting inquiry, and one of vital importance to the actuaries of fire-insurance companies, is the relative liability to fire of different classes of occupations and residences.  We already know accurately the number of fires which occur yearly in every trade and kind of occupation.  What we do not know, and what we want to know, is the proportion the tenements in which such trades and occupations are carried on, bear to the total number of houses in the metropolis.  The last census gives us no information of this kind, and we trust the omission will be supplied the next time it is taken.  According to Mr. Braidwood’s returns for the last twenty-one years, the number of fires in each trade, and in private houses, has been as follows:—­

Private Houses 4,638
Lodgings 1,304
Victuallers 715
Sale Shops and Offices 701
Carpenters and Workers in Wood 621
Drapers, of Woollen and Linen 372
Bakers 311
Stables 277
Cabinet Makers 233
Oil and Color men 230
Chandlers 178
Grocers 163
Tinmen, Braziers, and Smiths 158
Hooses under Repair and Building 150
Beershops 142
Coffee-shops and Chophouses 139
Brokers and Dealers in Old Clothes 134
Hatmakers 127
Lucifer-match makers l20
Wine and Spirit Merchants 118
Tailors 113
Hotels and Club-houses 107
Tobacconists 105
Eating-houses 104
Booksellers and Binders 103
Ships 102
Printers and Engravers 102
Builders 91
Houses unoccupied 89
Tallow-chandlers 87
Marine store Dealers 75
Saw-mills 67
Firework Makers 66
Warehouses 63
Chemists 62
Coachaakers 50
Warehouses (Manchester) 49
Public Buildings 46