After this faint and incomplete sketch of that which human science has been able to accomplish, it might be supposed that every inhabitant of the earth is impatient to make all this knowledge his own, that every one must desire to fill his mind with its treasures. Alas! the great majority of the human species is ignorant of even the elements of all this. Take away the ten millions of individuals, to whom we have already alluded, and who, numerically, are hardly to be counted in considering the population of the globe, all people imagine that the earth is a flat surface which extends to the limits of the horizon, and is covered with a blue cupola, called _heaven_. If you assert that the earth revolves, they laugh, and point to the motionless earth, and the sun which _rises_ on the right hand and _sets_ on the left, a manifest proof that the sun comes and goes. The poets will have it that the sun rises from his bed in the morning, and returns to it in the evening. People believe that the stars which shine by night, in the celestial vault, are simply ornaments, an agreeable spectacle, made to please our eyes, and that the moon is a beacon. Nobody inquires into the causes of the rain or fine weather, of heat or cold, of the winds or the tides. Every one shuts his eyes to natural phenomena, so as to avoid the trouble of explaining them. Nature is a shut book for the majority of mankind, who live in the midst of the most curious and various phenomena, but who occupy themselves in eating and drinking, and trying to harm their fellows. It is a sorrowful spectacle to behold humanity thus preoccupied by its more material necessities, and utterly without interest in any mental exertion, and one grieves to think that such is the condition of almost all the inhabitants of the globe. How far is he superior to the great mass of his fellows, who has cultivated his mind, enriched it with various and useful ideas, and appropriated to himself at least one branch of the varied tree of the exact sciences. What breadth and power must be acquired by a mind thus fortified! Strive, O my reader, to study and to learn. Initiate yourself into the secrets of nature, try to understand all that surrounds you, the universe and its infinite productions, admire the power of God in learning the wonders of His works. Then shall you not approach the tomb with your soul void as on the day of your birth. At the supreme hour of death you will be wise, instructed, and, finding yourself nearer to the sublime essence of superhuman beings, you will be eager to follow them into the ethereal spheres.