186 REPORT—1850. 
the current (in other words, the guantity of the current), and the electromotive force 
with which the current is sustained, which may be briefly termed its energy or inten- 
sity (provided the idea of quantity be kept distinct from this). 
The first object was to secure such units of comparison-for both these elements as 
should be at all times recoverable. This is given in respect of quantity by the rate 
of chemical action and the atomic weights. In respect of intensity of the current, we 
have no such fixed data, and the intensity of most voltaic arrangements cannot be 
relied upon as constants for comparison. But the elements of Daniell’s battery, and 
those of nitric acid batteries with negative surface of platinum, carbon, or cast iron, 
give an electromotive force or intensity that can be recovered with considerable ex- 
actitude, if uniformity of circumstances, materials, &c. be tolerably attended to. 
These, therefore, may be used to give a fixed and recoverable point ina galvano- 
metric scale of intensity. ; 
Now itso happens that if we assume the degrees of the scale to be of such a size 
that the intensity of Daniell’s (standard) elements shall be 60 of the degrees (tem- 
perature being 70° Fahr.) (60 being the most convenient number, by the way, for 
submultiples), that that of nitric acid batteries will be from 100° to 112° of the 
same degrees. The author therefore has always used this scale, to which all other 
voltaic arrangements can be referred (as shown in a table hereafter), which scale, he 
would suggest, would be most conveniently used in assigning the electromotive 
power of electric currents from any source. 
The mean results of careful experiments, tried directly and conversely, is that a 
voltaic current of one unit in quantity (or that from one grain of zinc electro-oxidized 
per minute) and of 100° intensity, represents a dynamic force of 3023 lbs. raised one 
foot high per minute. This datum is of great interest as a scientific truth in con- 
nection with the other correlative agents of nature (heat, electricity, light, and che- 
mical affinities, neuralgic power, &c.), most of which we may hope soon to see re- 
duced to a mutually comparable relation to each other, in terms of the great centre 
and medium of comparison, mechanical force. 
On Improvements in propelling and navigating Steam Vessels. 
By M. W. Rutuven. 
The principle of propulsion adopted ‘is the pressure or force obtained in the op- 
posite direction to the discharge of a fluid. 
Water is admitted through apertures in the bottom of the vessel, into a covered 
canal or pipe; at the termination of the canal or pipe is placed a water-tight case 
enclosing a horizontal wheel with floats, or blades forming compartments. The 
wheel and case are under the water-line of the vessel; the wheel is thus always im- 
mersed in the water supplied by the canal. From the water-tight case a pipe is 
taken to each side of the vessel, and on the outside end of each is attached a bent 
pipe, or nozle, moveable in a socket joint at, near, or above the usual water-line. 
On the power being applied to make the wheel in the case revolve, the water sup- 
plied by the canal is pressed out and discharged by the nozles, with a force corre- 
sponding to the velocity of the wheel ; the pressure to move the vessel depending on 
the area of the apertures where the water leaves the nozles. 
Each nozle is turned by a wheel on the deck, and without making any change of 
the power applied by the engine. When the vessel is going ahead with all the 
power, the nozles are placed in a horizontal line, discharging the water towards the 
stern. To make the vessel go slow, the nozles are pointed at an angle downwards, 
according as the speed is wished to be reduced ; and if required to remain stationary, 
they are pointed to discharge the water in a vertical direction. By pointing the 
nozles to the bows, the vessel goes astern; with a rate according to the angle of 
direction of the nozle. Toturn the vessel round to either side, one nozle is pointed 
to the bows, and the other to the stern. All these movements are made on the 
deck, without any change on the engine, or any communication with those in attend- 
ance on the engine; the vessel is also independent of the rudder, as it can be 
navigated without it, by moving the nozles as required, and turned by them when 
the rudder could not effect it. ; 
