During the latter part of the last century, the question arose among mathematicians—“to determine the best form that can be given to the sails of a windmill, according to their varying distances from the revolving vanes, and likewise from the centres of the revolution.” This is an excessively complex problem, for it is, in other words, to find the best possible position 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) Mäelzel’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.