among our most eminent botanists as to whether the Arctic flora was originally European or American. There is also an idea that at the beginning of the last Glacial period the Arctic flora was driven south, and, after the return of warmer times, followed the retreating ice, with the exception of those species that were stranded and had taken refuge on the mountain tops, the so-called Alpine flora. Further investigations in order to elucidate and solve these interesting botanical problems would be of the greatest value.

We have yet much to learn respecting the currents of air, the temperatures, and other matters connected with meteorology which, in all probability, will be found, in a great measure, to affect the climate conditions of lower latitudes. Further investigations in this particular branch would doubtless result in the attainment of knowledge that would be of great practical use and importance.

What has been designated as the Greenland fohn is an atmospheric condition prevailing at the same moment over different portions of the Arctic regions situated at wide distances apart, and of which at present little is known. At the Alert's winter quarters off the northeast coast of Grinnell Land in 1875, we experienced great fluctuations of temperature, varying no less than 55°; that is to say, that the thermometer would make a sudden and rapid rise from -20° to +35°, and sometimes this unusually high temperature, invariably accompanied by a south wind, would last for a great many days, thus occasioning us serious inconvenience from the unexpected warmth, for which we were entirely unprepared. These warm southerly winds were felt on the west coast of Greenland, between Ivigtut and Upernivik, precisely at the same time that they were experienced by us, thus pointing to the fact that the warm wave must have traveled at a prodigious rate, and from a considerable distance, in order that it should have been felt, practically, at the same time in places so widely separated. De Long also remarks an unusual rise of temperature in the month of October, when he was beset in the ice and drifting to the north of Herald Island, and this increase of temperature was always accompanied by a southeasterly wind. Immediately the wind veered round to the west, or even to the southwest, the temperature promptly fell.

This brings us to the equally important question of oceanology, which should comprise a complete knowledge not only of the surface currents in the Arctic seas, but also surface and deep-sea temperatures, formation, depth and nature of bottom, influence of tides, density of sea water, varying conditions of ice, and other matters connected with the hydrography of those regions. The strongest known currents that have an outlet from the north polar basin are undoubtedly those that flow to the southward down Baffins Bay and Davis Strait and along the east coast of Greenland. These are apparently uninfluenced by wind, and their drift is both regular and rapid throughout the year. The study of the system of these inflowing and outflowing currents is one of great complexity but of vast importance.

Tidal action has been observed in nearly every part of the Arctic regions that has been visited by man, but probably from a want of synchronous observations we have yet much to learn in this respect.

A more complete knowledge of the nature, character, and size of the icebergs and ice fields met in various parts of the polar regions, together with other glacial observations, would also be of exceptional interest. Nor must we omit from the results that are likely to accrue to science by continued exploration in the Arctic regions those connected with terrestrial magnetism and spectrum analysis, to say nothing of the importance of obtaining pendulum and auroral observations in high latitudes. Each and all of these are matters of the highest consequence and deserving of further investigation, and these investigations can only be carried out by competent observers on the spot.

I trust I have said enough to show the value and importance of further exploration in the ice-clad regions of the north. I have endeav ored to show as briefly as is compatible with the importance of the subject our knowledge of the north polar regions up to the threshold that bounds what I may designate the terra incognita of the Northern Hemisphere, and I have also attempted to point out the best means by which successful exploration in the unknown regions can be carried out. I would wish especially to lay stress on the fact that any advance into the undiscovered region must be regarded as a success, quite independ ent of the attainment of any position in near proximity to the pole. Therefore the route that is likely to lead to the discovery of the greatest extent of the unknown region, whether to the north, east, or west, is the one that should be followed in future exploration. If every nation that is represented at this congress-and I think the whole civilized world is represented-were to unite in their endeavors to dispatch expeditions to explore the hidden mysteries of the polar basin, France taking one section, the United States another, Germany a third, Great Britain, Sweden, Italy, Holland, and Norway others, then I am confident that in a short time that large blank space on our globe having the North Pole as its center will be as well known and as accurately charted as are the other known parts of the world. There is plenty of work to do, and there is plenty of room for every nation in this great and interesting scheme of exploration. The zeal, energy, and enthusiasm of those who have preceded us have already acquired for us a knowledge of vast terrritories that a century ago were as much a sealed book as the north and south polar basins are at the present day. Surely in this enlightened age we ought not to hold back where others in the past have led the way. Let us now in this congress use our utmost efforts to effect the exploration of those million and a half square miles of absolutely unknown region surrounding the northern axis of our globe. If we succeed in procuring the dispatch of even one wellorganized expedition we shall be satisfied that this congress, at any rate, has not met in vain.

THE ANIMAL AS A PRIME MOVER.'

By R. H. THURSTON.

PART I.-THE HUMAN ANIMAL AS A VITAL PRIME MOVER AND A THOUGHT MACHINE; THE ENERGETICS OF THE VITAL MACHINE; ITS

TRANSFORMATIONS.

The vital engine, the body of every vertebrate animal-from the human ruler of all, down to the lowest organism having a cartilaginous frame-is to-day well recognized as, in the engineer's classification, a "prime motor," in which the latent forces and energies of a combustible "food," of a fuel, as many suppose it, are evolved, transferred, and transformed to perform the work of the organism itself, to supply heat to keep it at the temperature necessary for the efficient operation of the machine, and for the performance of external work. The value of the machine as a prime mover is dependent upon the relation between this external work, so far as it can be applied to useful purposes as labor, and the costs of its production in fuel or energy supply, and in wear and tear and replacement, precisely as with any other machine of the class, whether the source of power be chemical, thermal, electrical, or vital.

The work of the machine is, however, a very different quality and is vastly different in quantity, useful work being compared with supplied energy, and incidental expenditures from that of any other known motor. In the water wheels and windmills, the office of the motor is simply that of transfer of energy of flowing currents of fluid, of water or of air, and without transformation, to mechanism suitable for giving it useful application. The heat engines develop energy previously "latent," potential, as the modern nomenclature would call it, into the kinetic form of thermal motion, and, by transformation, so far as may be practicable, into the dynamic form, make it available for work. Electro-dynamic machinery similarly makes available by transformation the energy of the electric current, and none of these machines has any other function than that of making useful some one energy previously stored by the operations of nature in such form as to be readily applied to his purposes by the hand of man.

From the Journal of the Franklin Institute, Vol. CXXXIX, Nos. 829 to 831, January, February, and March, 1895.

The vital machine, on the other hand, has purposes and performs offices of essentially different kinds. It must not only transform the latent energies of the supplies received by it into useful external work, but all its work being directed toward the sustenance and preservation of the contained soul, as its principal and always essential purpose, all its operations being automatic or self-directed, all its powers of transformation of energy are demanded for the production, by transformation, presumably, of (1) the vital forces and energies; (2) the physical energies demanded in constructing, rebuilding, and operating the animal frame; (3) the external work required to furnish the body supplies, to protect it from decay or injury, and to minister to the physical wants and ethical requirements of the personality of which it is at once the home and the vehicle.

This curious prime mover is thus an apparatus which, from familiar sources of energy, transfers and transforms, for its own purposes and applications, a variety of energies, performing a variety of work in various realms. The nature and composition of the sources of latent energy, always chemical compounds capable of oxidation, are well known; the character and method of many of the internal as well as of the external expenditures of energy are equally well understood; but there are a variety and considerable number of internal operations, involving transformations of energy, the nature and method of which are entirely beyond observation by any process of experimentation yet devised.

"Food" is taken into the body, enters into solution with the peptic fluids, elaborated from previously supplied nutriment, is absorbed into the circulation, and disappears from our sight and reach; heat, carbondioxide, vapor of water, various salts, and a considerable proportion of unutilized nutriment are rejected from the system, and work is performed as the product of transformed energies and in large amount, both within the machine and upon external bodies. A chain of energy transformations is in continuous operation, of which we see the two ends, so far as the vital machine is concerned, but of which we only get occasional glimpses between the extremities, and some of the links of which are, as yet, undiscovered and unknown. It is certain that the series of changes, material and kinetic, involves familiar methods of transformation, and it is hardly less certain that singular and probably wonderful and unknown processes of energy development and transformation are concealed within this miracle among machines.

Possibly a study of the present state of scientific research relative to this machine may give at least some idea of the importance and complexity of the problems here placed before the man of science and the engineer, if not give a clew to their final solution.

The source of power in the animal machine is invariably the stored chemical energy of vegetation, the potential energy of the hydrocarbons and other compounds contained in all plants, and capable of uniting

with oxygen to form carbonic acid, water, and salts capable of solution in water. It is possible, but perhaps not probable, that other substances and energies forming constituents of these compounds may exist, having eluded the investigating chemist and physicist; but this is thought unlikely. We probably know precisely what enters the animal prime motor, and what are the sources of all its energies. Food and air are the two known elements of all its powers. It is also possible, but probably not the fact, that this machine may drink in from the surrounding ether some portion of its energy in forms still undetected and unsuspected. We are compelled, for the present, certainly, to assume that all the energies developed and applied in the vital machine are initially latent in vegetable matter, air, and water. This organic substance is derived by the carnivorous animals indirectly through the other creatures, all of which live upon vegetation directly. The organic forces of plant life derive all energy from the inorganic world of minerals and from the gases of the atmosphere by utilizing the primary energy of solar rays in the chlorophyll with which every leaf is provided, as the active agent in that transformation. The vital machine thus ultimately derives all its energies from the sun.

Food is the material in which are stored the substances supplied to the vital machine as the reservoir of the potential energy from which the required energies, in various active forms, may be derived, as demanded, to perform the work of the body and the mind. It consists of a mixture of edible and other matter, the former being that part from which energy is derivable; the latter being indigestible and unassimilable and only useful in promoting, by mechanical irritation, the action of the digestive system.

All foods contain:

Water-required for solution of nutrients.
Nutrients-protein, fats, carbohydrates.

Innutrient matter.

Protein consists of the albuminoids, and, in vegetable matter, the amides, a less valuable portion of the food. The white of egg, the fibrine of meat, and the gluten of wheat are illustrations of albuminoid compositions.

Fats, such as those of meat, and the greases of vegetation, the oils of the animal and vegetable compounds extractable by ether constitute the basis of construction of the fats of the body and of a part of the nerve and brain substance.

Carbohydrates are the starches and sugars of the vegetable.

Salts are found in both animal and vegetable foods, and are in some cases essential elements of the compositions making up the body, though not, in the ordinary sense, digestible and nutrient.

Mineral matters constitute, in the case of the vegetable foods, the principal portion of the innutrient matter of food, and form the ash when the plant is burned. In some cases these mineral matters serve