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Ordinary Meeting, April 3rd, 1866. 
R. Angus Smith, Ph.D., F.R.S., &c., President, in the Chair. 
Messrs. Win. Brockbank and G. C. Lowe were appointed 
Auditors of the Treasurer’s accounts. 
Mr. Bin ney,F.R.S., said that he had observed the humming 
bird hawkmoth ( Macroglossa Stellnlarum ) during the past 
summer in far greater abundance than he ever remembered 
having seen it before. In the month of August, he saw 
upwards of a hundred of them in a garden near Grimsby, 
were they appeared to prefer the common lavender flower for 
food to any other in the place. Again in the first week of 
October, he observed upwards of twenty in a garden at 
Douglas, in the Isle of Man. Here they preferred to feed 
on heliotrope before other flowers. It was very interesting 
to watch these moths hovering over the flowers, and whilst 
on the wing extracting their food. They appeared very 
wary and shy after any attempt being made to capture them, 
but if you merely observed without making any attempt to 
molest them they would continue their feeding in confidence, 
and you could "watch them at your leisure. So a great deal 
of the shyness and caution for which the little creature has 
got the credit of, is probably more due to the persevering 
efforts of its enemies to capture it than any natural fear of 
man. 
A paper was read “ On a Logical Abacus,” by W. S. 
Jevons, Esq., M.A. 
. The author believed that this was the first attempt, or at 
all events, the first successful attempt, to reduce the pro- 
cesses of logical inference to a mechanical form. The purpose 
of this contrivance is to show the simple truth, and the perfect 
Pboceedings— Lit. & Phil. Society.— Voe, V. — No. 14 — Session 1865-6. 
