182 Natural and Artificial Flight. (April, 
In making bars the regulus is calcined dead, in accordance 
with Napier’s recommendation; but at Guayacan it is, 
before entering the calciners, crushed between Cornish rolls 
to 1-8th of an inch, instead of being disintegrated in water, 
as is done at the Compania. 
The result of the fusion of the calcined regulus is a bath 
of 96 per cent metal, which is run into bars, and a rich matt 
of 70 percent. This 70 per cent matt is then smelted into 
blister copper and a rich slag. The blister copper is refined 
in charges of 15 to 20 tons. Willow rods are used in polling, 
and in addition to anthracite dried aloe stems are thrown 
upon the bath of metal. 
Mr. Francis, the smelter, to whose intelligent superin- 
tendence Guayacan owes much of its prosperity, says he 
can make a ton of refined ingots out of 13 per cent ore with 
5 tons of coal. © 
IlIL NATURAL AND ARTIFICIAL FLIGHT. 
eo 
‘i ever the important problem of Artificial Flight is to 
alt be solved, it is reasonable to conclude that the same 
laws and forces which produce Natural Flight must be 
discovered and applied. Imbued with this belief, Dr. ]. 
Bell Pettigrew, of the Royal College of Surgeons, Edinburgh, 
has made a series of elaborate inquiries into the structure 
and function of natural wings, and the peculiar properties 
requisite in artificial wings to produce artificial flight. Dr. 
Pettigrew has been engaged in these researches since 1865, 
and has carefully analysed, figured, and described, not only 
the movements of the wings of insects, bats, and birds, but he 
has also examined in detail the movements of a large number 
of animals fitted for swimming, such as the otter, seal, 
sea bear, walrus, penguin, turtle, crocodile, porpoise, fish, &c. 
By comparing the flippers of the seal, sea bear, and walrus 
with the fin and tail of the fish ; and the wing of the penguin 
(a bird which is incapable of flight, and can only swim and 
dive) with the wing of the inse¢t, bat, and bird, he has been 
able to show that a close analogy exists between the flippers, 
fins, and tails of sea mammals and fishes on the one hand, 
and the wings of insects, bats, and birds on the other; in 
fact, that theoretically and practically these organs, one and 
all, form flexible helices or screws, which, in virtue of their 
rapid reciprocating action, operate upon the water and air 
after the manner of double inclined planes. 
