Ammeter the effect – the instruments were called "multipliers". The word "rheoscope" as a detector of electrical currents was coined by Sir Charles Wheatstone about 1840 but is no longer used to describe electrical instruments. The word makeup is similar to that of "rheostat" (also coined by Wheatstone) which was a device used to adjust the current in a circuit. Rheostat is a historical term for a variable resistance, though unlike rheoscope may still be encountered. The D'Arsonval galvanometer is a moving coil ammeter. It uses magnetic deflection, where current passing through a coil placed in the magnetic field of a
Coal Measures Group the: In South Wales, the larger part of what had been the Upper Coal Measures now forms the Pennant Sandstone Formation in the overlying Warwickshire Group. The South Wales Coal Measures Group is preceded (underlain) by the Marros Group. Coal Measures Group The Coal Measures Group is a lithostratigraphical term coined to refer to the coal-bearing succession of rock strata which occur in the United Kingdom within the Westphalian Stage of the Carboniferous Period. Other than in Northern Ireland the term is now obsolete in formal use and is replaced by the Pennine Coal Measures Group, Scottish Coal Measures Group