certain minds. In that curious olla podrida of fact and fiction, "The Curiosities of Literature," D'Israeli gives a list of six of these problems, which he calls "The Six Follies of Science." I do not know whether the phrase "Follies of Science" originated with him or not, but he enumerates the Quadrature of the Circle; the Duplication, or, as he calls it, the Multiplication of the Cube; the Perpetual Motion; the Philosophical Stone; Magic, and Judicial Astrology, as those known to him. This list, however, has no classical standing such as pertains to the "Seven Wonders of the World," the "Seven Wise Men of Greece," the "Seven Champions of Christendom," and others. There are some well-known follies that are omitted, while some authorities would peremptorily reject Magic and Judicial Astrology as being attempts at fraud rather than earnest efforts to discover and utilize the secrets of nature. The generally accepted list is as follows:

1. The Quadrature of the Circle or, as it is called in the vernacular, "Squaring the Circle."
2. The Duplication of the Cube.
3. The Trisection of an Angle.
4. Perpetual Motion.
5. The Transmutation of the Metals.
6. The Fixation of Mercury.
7. The Elixir of Life.

The Transmutation of the Metals, the Fixation of Mercury, and the Elixir of Life might perhaps be properly classed as one, under the head of the Philosopher's Stone, and then Astrology and Magic might come in to make up the mystic number Seven.

The expression "Follies of Science" does not seem a very appropriate one. Real science has no follies. Neither can these vain attempts be called scientific follies because their very essence is that they are unscientific. Each one is really a veritable "Will-o'-the-Wisp" for unscientific thinkers, and there are many more of them than those that we have here named. But the expression has been adopted in literature and it is just as well to accept it. Those on the list that we have given are the ones that have become famous in history and they still engage the attention of a certain class of minds. It is only a few months since a man who claims to be a professional architect and technical writer put forth an alleged method of "squaring the circle," which he claims to be "exact"; and the results of an attempt to make liquid air a pathway to perpetual motion are still in evidence, as a minus quantity, in the pockets of many who believed that all things are possible to modern science. And indeed it is this false idea of the possibility of the impossible that leads astray the followers of these false lights. Inventive science has accomplished so much—many of her achievements being so astounding that they would certainly have seemed miracles to the most intelligent men of a few generations ago—that the ordinary mind cannot see the difference between unknown possibilities and those things which well-established science pronounces to be impossible, because they contradict fundamental laws which are thoroughly established and well understood.

Thus any one who would claim that he could make a plane triangle in which the three angles would measure more than two right angles, would show by this very claim that he was entirely ignorant of the first principles of geometry. The same would be true of the man who would claim that he could give, in exact figures, the diagonal of a square of which the side is exactly one foot or one yard, and it is also true of the man who claims that he can give the exact area of a circle of which either the circumference or the diameter is known with precision. That they cannot both be known exactly is very well understood by all who have studied the subject, but that the area, the circumference, and the diameter of a circle may all be known with an exactitude which is far in excess of anything of which the human mind can form the least conception, is quite true, as we shall show when we come to consider the subject in its proper place.

These problems are not only interesting historically but they are valuable as illustrating the vagaries of the human mind and the difficulties with which the early investigators had to contend. They also show us the barriers over which we cannot pass, and they enforce the immutable character of the natural laws which govern the world around us. We hear much of the progress of science and of the changes which this progress has brought about, but these changes never affect the fundamental facts and principles upon which all true science is based. Theories and explanations and even practical applications change or pass away, so that we know them no more, but nature remains the same throughout the ages. No new theory of electricity can ever take away from the voltaic battery its power, or change it in any respect, and no new discovery in regard to the constitution of matter can ever lessen the eagerness with which carbon and oxygen combine together. Every little while we hear of some discovery that is going to upset all our preconceived notions and entirely change those laws which long experience has proved to be invariable, but in every case these alleged discoveries have turned out to be fallacies. For example, the wonderful properties of radium have led some enthusiasts to adopt the idea that many of our old notions about the conservation of energy must be abandoned, but when all the facts are carefully examined it is found that there is no rational basis for such views. Upon this point Sir Oliver Lodge says:

One would naturally suppose that the extensive diffusion of sound scientific knowledge which has taken place during the century just past, would have placed these problems amongst the lumber of past ages; but it seems that some of them, particularly the squaring of the circle and perpetual motion, still occupy considerable space in the attention of the world, and even the futile chase after the "Elixir of Life" has not been entirely abandoned. Indeed certain professors who occupy prominent official positions, assert that they have made great progress towards its attainment. In view of such facts one is almost driven to accept the humorous explanation which De Morgan has offered and which he bases on an old legend relating to the famous wizard, Michael Scott. The generally accepted tradition, as related by Sir Walter Scott in his notes to the "Lay of the Last Minstrel," is as follows: