i88i.] 
Probable Extension of Solar Physics . 
481 
practical working, and which enable it to produce results 
very different from anything ever realised, e.g., at Leaming- 
ton. Nor is he apparently able to point out any advances 
in irrigation, or to show the way of avoiding its besetting 
difficulties. 
To prevent all misunderstanding it may be well to state 
that the present writer, though he has had thirteen years’ 
experience in different processes of sewage-treatment, has 
no interest in the success of any scheme, either as a share- 
holder, patentee, or official, and judges from the point of 
view of an independent outsider. 
VI. ON THE PROBABLE EXTENSION OF SOLAR 
PHYSICS TO MATTERS AFFECTING THE 
AGRICULTURIST, MERCHANT, AND MAN OF 
SCIENCE. 
By A. H. Swinton. 
S HE scientific mind has of late years been gradually 
awakened to the important fadt that a certain class of 
natural phenomena, on which mankind are greatly 
dependent for the future development of their resources, are 
immediately controlled by, and in diredt subjedfion to, the 
central luminary of our system. Terrestrial magnetism, 
eledtrical adtivity, periodical variations in temperature, pe- 
riodicity of wind disturbance, and annual rainfall have espe- 
cially occupied attention in this respedt ; and their various 
phases following the vacillation of the spots on the sun’s 
photosphere have been observed, recorded, and finally drawn 
up in tables and diagrams. From these indices we may now 
glean that as the sun’s atmosphere of light, every eleven 
years or so, wanes and again replenishes itself, so will cold 
and warm seasons, cyclones and rainfall, disturbances along 
the eledtric wire, oscillations of the compass, and other 
symptoms in our sky and soil that receive the solar rays, 
follow each other in due sequence. Medical science, too, 
has not been oblivious to these periods of solar energy and 
