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Chemistry and Physics. 117 
them in particular modes, they may have their poles reversed or be de- 
prived of their magnetism, or hardened non-magnetic steel may be in- 
stantly rendered magnetic ; and he considered that these facts, which 
he had long since made public, should be kept before the mind in such 
investigations as the very oriyinal and interesting facis just brought un- 
der the notice of the Section.——Prof. Farapay after very briefly, yet 
lucidly, explaining to the Section the leading distinctions between para- 
magnetic and diamagnetic bodies, and their behavior in the magnetic 
field, said, that it was conceded on all hands that the explanation was 
erroneous which Pliicker had given of the phenomena which he first 
discovered connected with the branch of research to which Prof. Tyn- 
dall had just been directing their attention, and which he was so ably 
hunting down. But when he said the original explanation of Pliicker 
Was erroneous, he did not mean that as the slightest disparagement to 
that philosopher. It was well understood by all who had any preten- 
sions to scientific knowledge since the days of Bacon, that it 
through the mist of error that the most important discoveries had to be 
made, and that in pursuing any research it was much better in the first 
Stages of the inquiry to have erroneous views, than to be without any 
Views that would tend to connect the scattered facts. For his part, he 
was not ashamed to own that he wasa learner, and that in almost 
every instance it was through the clouds of error that he arrived at 
the conclusions which satisfied him most. nd as his mathematical skill 
and acquirements were o means such as to entitle him to despise 
Instruction, he should feel particularly grateful to his mathematieal 
niends present, Dr. Whewell and others, if they would explain to him 
magnetic field, if it was known.—Dr. WHEWELL explained how the 
force would be distributed upon the old theory of magnetic lines ; but 
he said he was aware, and he believed it was now generally admitted, that 
this theory must be greatly modified, if not given entirely up. But as 
in a locality not only visible, but in every way convenient for experi- 
