properties of medicine is quite different from knowing how to apply them; but when you consider that 
the properties in question would be but little studied but for the purpose of relieving human 
suffering; that their union under both points of view, abstract and practical, sustains the interest 
and saves time, you return to what at first seemed defective. "Life is short, and art is long." 
These memorable words of Hippocrates, let me add, whose truth has not been impaired by the 
materia-medica or therapeutics, unitedly or separately, deserve to be remembered in the distribution 
of the studies of youth. 
Ampère thought he had succeeded in avoiding entirely all repetitions; he flattered himself that 
henceforth each science could be studied without any trace of syllogistic circles; that, while 
engaged in one study, it would never be necessary to refer to the science coming after on the 
synoptical table. 
An illustrious metaphysician did not believe this methodical course possible unless in the science 
of abstract mathematics. Readers, he said, must trust; they must be willing to give credit for a 
time, if they wish to be satisfied; for geometers alone always pay cash. 
Could Ampère always pay cash, as Malebranche expresses it, even in applied mathematics? If time 
permitted I could easily prove, I believe, that on this point our illustrious colleague deceived 
himself. In his table I see, for example, astronomy before physics; and, consequently, before 
optics. How, then, in the first lessons of uranography and the first study of the diurnal movements 
of the heavens, could the professor explain the use of the telescopes, of the lines placed in the 
common focus between the object and eye glasses? What could he say, without asking for credit of the 
atmospheric refractions which so perceptibly deform the circular diurnal orbits of the stars? All 
astronomers would agree with me that it is very unnatural that heliostatics, or the demonstration of 
the Copernican system, should precede the exposition of the laws of Kepler, considered as simple 
results of observation. 
I could multiply these remarks, but they would not prevent Ampère’s classification from being 
very superior to all those preceding it; it would require but a few suppressions and some 
rearrangement of points of slight importance to make it as perfect as would be compatible with the 
nature of the subject. It can be unhesitatingly affirmed that its various parts bear the indelible 
stamp of an erudition as remarkable for its extent as its profoundness. 
Ampère had not only essayed the vast problem of a general classification of the sciences, but had 
also been engaged in introducing classifications into the physical and natural sciences separately. 
The chemical classifications proposed by the learned academician could even now be published with 
profit. They would prove – and how strange the fact – that, during one of the last revolutions 
in the science, Ampère, the geometer Ampère, was always in the right, even when his opinions were 
opposed to those of nearly all the chemists of the world.