’When the valve is partially closed, the water escapes more slowly; and the rise of the roller, and consequently the taper of the iron, are more gradual.

’Any rate of taper may thus be had by regulating the rise of the opening of the escape-valve.  If the water is all driven out before the bar is entirely through the rollers, the top roller ceases to rise, and the iron becomes parallel from that point.  Then, if the ends of the bar be reversed, and it be again passed between the rollers, the parallel portion will become tapered; thus we can get a bar.’

At the same time, a ‘Thermometrical Ventilator’ was exhibited, which is described as circular in form, with a well-balanced movable plate.  ’Upon the side of the valve is an inverted syphon, with a bulb at one end, the other being open; the lower part of the tube contains mercury; the bulb, atmospheric air.  An increase of temperature expands the air in the bulb, drives the mercury down one side and up the other, thereby destroying the balance, and causing the valve to open by turning on its axis.  A diminution of temperature contracts the air in the bulb, causes the mercury to rise in the side of the tube, and closes the valve.’  Besides this, there was ’an improved magneto-electric machine, for medical use, with a new arrangement, by which the shock is graduated by means of a glass tube, in which a wire is made to communicate with water, so as to produce at first a slight shock; by gradually pressing down the wire attached to a spiral spring, the shock is received in its full force.’

It now appears that Mr Robertson of Brighton claims priority of discovery touching the boring power of Pholades.  His statements are founded on daily observation of the creatures at work for three months.  ‘The Pholas dactylus’ he says, ’makes its hole by grating the chalk with its rasp-like valves, licking it up, when pulverised, with its foot, forcing it up through its principal or bronchial syphon, and squirting it out in oblong nodules.  The crypt protects the Pholas from confervae, which, when they get at it, grow not merely outside, but even within the lips of the valves, preventing the action of the syphons.  In the foot there is a gelatinous spring or style, which, even when taken out, has great elasticity, and which seems the mainspring of the motions of the Pholas dactylus.’

At last, steam communication with Australia seems about to become a reality, for the first vessel is announced to start in May for Sydney, to touch at the Cape and other colonies on her way out; and accommodation is promised for two hundred passengers of different classes.  There is also a project on foot for a line of steamers from Panama to Australia, and to Valparaiso, which, if brought into operation, will make a voyage round the world little more than a bagman’s journey.  Apropos of Australia, Mr Clarke, who first predicted that gold would be found in that country,