[411] Instruction pour les Jardins. Paris, 1730, 4to, i. p. 263. The author says that ice in summer is indeed useful; but, as a gardener, he wishes that frost could be prevented; and that ice might be imported from the North, as olives and oranges are from the South. Some years ago, as no ice could be procured on account of the great mildness of the preceding winter, the merchants at Hamburg sent a ship to Greenland for a load of it, by which they acquired considerable profit.
[412] For the above account of the mode of collecting the ice at Wenham Lake, we are indebted to the ‘Illustrated London News’ for May 17, 1845.
HYDROMETER.
This instrument, called in Latin hydrometrum, hygroscopium, hygrobaroscopium, hydroscopium, areometrum, and baryllion, serves to determine the weight or specific gravity of different fluid masses, by the depth to which it sinks in them.
The laws respecting the comparative specific gravity of fluids and solid bodies immersed in them were discovered by Archimedes, when he tried the well-known experiment, by order of Hiero king of Sicily, to find the content of a golden crown, made for that sovereign. Upon these is founded the construction of the hydrometer; and it is not improbable that Archimedes, who was killed in the year 212 before the Christian æra, was the inventor of it, though no proofs to warrant this conjecture are to be found in the writings of that great man, or in those of any other author.
The oldest mention of the hydrometer occurs in the fifth century, and may be found in the letters of Synesius to Hypatia. Of the lives of these two persons I must here give some anecdotes, as they deserve to be known on account of the singular fate which attended them. Hypatia was the daughter of Theon, a well-known mathematician of Alexandria, some of whose writings are still extant. By her father she was instructed in mathematics, and from other great men, who at that time abounded in Alexandria, she learned the Platonic and Aristotelian philosophy, and acquired such a complete knowledge of these sciences, that she taught them publicly with the greatest applause. She was young and beautiful, had a personable figure, was sprightly and agreeable in conversation, though at the same time modest; and she possessed the most rigid virtue, which was proof against every temptation. She conducted herself with so much propriety towards her lovers, that they never could obtain more than the pleasure of her company and of hearing her discourse; and with this, which they considered as an honour, they were contented. Those who wished to intrude further were dismissed; and she destroyed the appetite of one who would not suffer her to philosophise, by means of some strong preparation, which, as far as I know, remained a secret. She was not baptized, and with all her knowledge, adopted the blind superstition of paganism. Had she been a Christian, and suffered a cruel death from heathen persecution, she would have merited a place in the martyrology of the saints: but the case was reversed; for, by the conduct of the Christians towards her, she became entitled to have her name enrolled in the martyrology of the philosophers.
The patriarch of Alexandria, at the time when she lived, was Cyril, whose family for a hundred years before had produced bishops, who were of more service to their relations than to the church. This prelate was a proud, litigious, vindictive and intolerant man, who thought every thing lawful which he conceived to be for the glory of God; and who, as prosecutor and judge, condemned Nestorius without hearing his defence. In the city of Alexandria, which was then very flourishing on account of its commerce, the emperor allowed greater toleration than he imagined could be justified to the clergy in any other place; and it contained a great many Jews, who carried on an extensive trade, as well as a number of pagan families who were of service to the city, or at least did it no harm. This, in the eyes of Cyril, was not proper; he would have the sheep-fold clean, and the Jews must be banished. Orestes, however, the governor, who was a man of prudence, and better acquainted with the interests of the city, opposed a measure that was likely to be attended with mischief, and he even caused to be condemned to death a Christian profligate, who had done some injury to the Jews. This malefactor was, by the order of Cyril, buried in the church as a martyr; and he immediately collected five hundred monks, who ill-treated Orestes in the streets, and excited an insurrection among the people, who plundered the unfortunate Jews, and expelled them from a city in which they had lived since the time of Alexander the Great.
Cyril, observing one day a great number of horses and servants belonging to persons of the first rank, before a certain house in the city, inquired the cause of their being assembled in that manner. He was informed that the house was the habitation of the celebrated female philosopher Hypatia, who, on account of her extensive learning and eminent talents, was visited not only by people of the highest distinction, but even by the governor himself. This was sufficient to excite the bishop’s jealousy against the unbelieving Hypatia, and he resolved to effect her ruin. As he had instigated the people against the Jews, he in like manner encouraged them to attack Hypatia. They seized her in the street, hurried her to the church, stripped off her clothes, tore her flesh to pieces with potsherds, dragged her mangled limbs about through the city, and at length burned them. This bloody tragedy, which took place in the year 415, could tend only to inspire the heathens with a greater hatred to Christianity, and to make sensible Christians ashamed of the conduct of their brethren. To Cyril, however, it occasioned no shame; on the contrary, he endeavoured to divert the emperor from punishing those who had been guilty of so gross a violation of the principles of justice, and in this he was assisted by his numerous adherents and friends. In some circumstances of this relation historians are not agreed, but they all concur in bestowing praise on Hypatia, whose memory was honoured and preserved by her grateful and affectionate scholars[413].