THE 



GEOLOGICAL MAGAZINE. 



NEW SERIES. DECADE II. VOL. II. 



No. III.— MARCH, 1875. 



a 



OIK-IO-UDsT-A-ID ABTICLBS. 



I. — "Uniformity" and " Vulcanicity." 

 By the Kev. 0. Fisher, M.A., F.G.S. 



OME geologists there are who are prevented from carrying out 

 10 on an extended scale observations in the field. They may 

 well envy those who have the strength, leisure, freedom from local 

 duties, and means to travel. Such accurate descriptions as they 

 receive from a pen like Mr. Judd's, enable them to see with other 

 eyes, and to test the theories which they spin out of their brains by 

 wider information. They must accept their position, and either 

 speculate, or do nothing, in their favourite science. Happily Mr. 

 Judd admits that speculation has its value, and Mr. Clifton Ward is 

 of the same opinion. 



But we are warned not to " abandon those safer methods of 

 inquiry based on the doctrine of Uniformity," nor " to revert to the 

 earlier methods — in effect, to substitute cosmogony for geology." 1 



What is meant by the doctrine of Uniformity ? If it be simply 

 that like forces have produced like results in all former times to 

 what they produce at present, — in other words, that the laws of 

 nature have never changed, — then no doctrine can be more certain. 

 But if it teaches that " all things continue as they were from the 

 beginning of the creation," — in other words, that the forces of nature 

 act upon matter which has always been in the same condition as at 

 present, — then I submit that the doctrine of Uniformity itself ought to 

 be " abandoned." To apply the principle to Vulcanology : " It would 

 be very wonderful, but not an incredible result, that volcanic action 

 has never been more violent on the whole than during the last two 

 or three centuries ; but it is as certain that there is now less volcanic 

 energy in the whole earth, than there was a thousand years ago, as 

 it is that there is less gunpowder in a " Monitor," after she has been 

 seen to discharge shot and shell, whether at a nearly equable rate 

 or not, for five hours without receiving fresh supplies, than there 

 was at the beginning of the action." 2 



If the doctrine of Uniformity in this sense be untenable in its 

 application to the condition of the earth in all past time, then we 

 are necessarily led backwards to cosmogony ; and I cannot see why 

 our science should not be permitted to connect itself with cosmogony 

 at the one extremity, as it has lately become firmly united to 

 archeeology at the other. "The earlier methods" led often to 



1 Mr. Judd, On Volcanos, Geol. Mag. Dec. II. Vol. II. p. 3. 



2 Thomson, On the Secular Cooling of the Earth, Nat. Phil. p. 714. * 



DECADE II. — VOL. II. NO. III. 7 



