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Replagegos Omnifurian Directory 07
Page 09
We have said that every substance has its own distinctive spectrum, and it might be thought that, when a list of the spectra of different substances has been prepared, spectrum analysis would become perfectly straightforward. In practice, however, things are not quite so simple. The spectrum emitted by a substance is influenced by a variety of conditions. The pressure, the temperature, the state of motion of the object we are observing, all make a difference, and one of the most laborious tasks of the modern spectroscopist is to disentangle these effects from one another. Simple as it is in its broad outlines, spectroscopy is, in reality, one of the most intricate branches of modern science.
The campaign of B.C. 215 was not marked by any decisive events. The Consuls were Q. Fabius Maximus (whose plan of conducting the war had been fully vindicated by the terrible defeat of Cannae) and Tiberius Sempronius Gracchus. With the advance of spring Hannibal took up his camp on Mount Tifata, where, while awaiting the arrival of re-enforcements from Carthage, he was at hand to support his partisans in Campania and oppose the Roman generals in that province. But his attempts on Cumae and Neapolis were foiled, and even after he had been joined by a force from Carthage (very inferior, however, to what he had expected), he sustained a repulse before Nola, which was magnified by the Romans into a defeat. As the winter approached he withdrew into Apulia, and took up his quarters in the plains around Arpi. But other prospects were already opening before him. In his camp on Tifata he had received embassies from Philip, king of Macedon, and Hieronymus of Syracuse, both of which he had eagerly welcomed, and thus sowed the seeds of two fresh wars, and raised up two formidable enemies against the Roman power.
That there is a close likeness between all these bodies is obvious from the fact that when any of them is strongly heated, or allowed to putrefy, it gives off the same sort of disagreeable smell; and careful chemical analysis has shown that they are, in fact, all composed of the elements carbon, hydrogen, oxygen, and nitrogen, combined in very nearly the same proportions. Indeed, charcoal, which is impure carbon, might be obtained by strongly heating either a handful of corn, or a piece of fowl's flesh, in a vessel from which the air is excluded so as to keep the corn or the flesh from burning. And if the vessel were a still, so that the products of this destructive distillation, as it is called, could be condensed and collected, we should find water and ammonia, in some shape or other, in the receiver. Now ammonia is a compound of the elementary bodies, nitrogen and hydrogen; therefore both nitrogen and hydrogen must have been contained in the bodies from which it is derived.
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