The Great Western Railway has always been famed for the wonderful engineering difficulties which were grappled with by the daring Brunel, and many evidences of his skill are apparent to the traveller on that line. But even Brunel did not conceive the bold idea of piercing a tunnel twenty-six feet in diameter, and four and a half miles in length, beneath the bed of the Severn. But this great work has now been in progress for some years, and the operations latterly have been pushed forward with such rapidity by three thousand busy men, that its completion may soon be looked forward to. The tunnel will shorten considerably the distance between London and South Wales. It is constructed so as to dip considerably towards the centre, to which point any water will naturally gravitate. Here it will enter a drainage subway, which will carry it to the Welsh side, to be pumped up into the river. The great difficulty which the workers have had to contend with is the irruption of vast bodies of water from local springs. The crown of the tunnel lies at a depth of from eighty to a hundred feet beneath the bed of the river. In these days of quick communication by telegraph and telephone, it is strange to see how it becomes occasionally convenient to employ ‘the bird of the air’ to ‘carry the voice.’ In Haddingtonshire, at the Penston Colliery, messages are carried from the pits to the offices, a distance of more than six miles, by pigeons, and they accomplish the work in about as many minutes. Telegrams are found to take about an hour in executing the same business, and telephones are inadmissible, because as yet no plan has been found by which the sounds can be permanently recorded. In a recent lecture on Cholera and its Prevention, Professor de Chamont called attention to the very common and erroneous idea that tobacco-smoke, camphor, and other strongly smelling compounds act as disinfectants. He pointed out that although chlorine, sulphurous acid gas, and carbolic acid may under certain conditions be safely regarded as true disinfectants, the best and most efficient known is _fire_. He also, in speaking of sulphurous acid gas, generated by burning sulphur, showed that a ready way of facilitating combustion was first of all to pour upon the brimstone a little alcohol.