osition at an infinity of varied distances and at an
infinity of points on the arm. There were a thousand futile attempts to
answer the query on the part of the most illustrious mathematicians, and
when at length, an undeniable solution was discovered, men found that
the wings of a bird had given it with absolute precision ever since the
first bird had traversed the air.

(*17) He observed a flock of pigeons passing betwixt Frankfort and the
Indian territory, one mile at least in breadth; it took up four hours
in passing, which, at the rate of one mile per minute, gives a length
of 240 miles; and, supposing three pigeons to each square yard, gives
2,230,272,000 Pigeons.--"_Travels in Canada and the United States," by
Lieut. F. Hall._

(*18) The earth is upheld by a cow of a blue color, having horns four
hundred in number."--_Sale's Koran_.

(*19) "The _Entozoa_, or intestinal worms, have repeatedly been observed
in the muscles, and in the cerebral substance of men."--See Wyatt's
Physiology, p. 143.

(*20) On the Great Western Railway, between London and Exeter, a speed
of 71 miles per hour has been attained. A train weighing 90 tons was
whirled from Paddington to Didcot (53 miles) in 51 minutes.

(*21) The _Eccalobeion_

(*22) Maelzel's Automaton Chess-player.

(*23) Babbage's Calculating Machine.

(*24) _Chabert_, and since him, a hundred others.

(*25) The Electrotype.

(*26) _Wollaston_ made of platinum for the field of views in a telescope
a wire one eighteen-thousandth part of an inch in thickness. It could be
seen only by means of the microscope.

(*27) Newton demonstrated that the retina beneath the influence of the
violet ray of the spectrum, vibrated 900,000,000 of times in a second.

(*28) Voltaic pile.

(*29) The Electro Telegraph Printing Apparatus.

(*30) The Electro telegraph transmits intelligence instantaneously- at
least at so far as regards any distance upon the earth.

(*31) Common experiments in Natural Philosophy. If two red rays from two
luminous points be admitted into a dark chamber so as to fall on a
white surface, and differ in their length by 0.0000258 of an inch,
their intensity is doubled. So also if the difference in length be any
whole-number multiple of that fraction. A multiple by 2 1/4, 3 1/4, &c.,
gives an intensity equal to one ray only; but a multiple by 2 1/2, 3
1/2, &c., gives the result of total darkness. In violet rays similar
effects arise when the difference