406 Intelligence and Miscellaneous Articles. 



mean temperature of o, 10 at the bottom of the sea. At less depths 

 I always observed higher temperatures. 



I place very little reliance on the two experiments of Professor 

 Nordenskiold. They were made in winter, on the coasts of the 

 Island of Aland — at a depth of 21 feet, and at a distance of 100 feet 

 from the coast — with a single alcohol thermometer provided with a 

 mercury index. Neither the author nor M. Edlund describes the in- 

 strument ; they do not state whether it was protected from, or ex- 

 posed to pressure ; and no proof is given that the unique indication 

 derived from the bottom of the sea was exact. I may venture to 

 advise readers desirous of becoming acquainted with the minute 

 precautions which, in experiments of this kind, are necessary in order 

 to gain for the results the confidence of physicists, to refer to the 

 memoir I published in 1848 and 1849 in the Voyages de 'la Recherche,' 

 and in the Annates de Chimie et de Physique. To avoid the incessant 

 recommencement of the study of a question, it is necessary to con- 

 sult the works of those by whom we have been preceded. I have 

 carefully analyzed those of Scoresby and of Parry, who, in 1811 

 and 1827, had already observed, on many occasions, temperatures of 

 the sea below zero, both at the surface and at depths varying from 

 90 to 1314 metres. M. Edlund will find the tabular statement of 

 them in my memoir. Doubtless the procedure and the instruments 

 of the English navigators are not beyond the reach of criticism ; but 

 the fact of the depression, below zero, of the temperature of sea- 

 water was established by them at the above period, and has since 

 been verified by other travellers. 



ON THE ANCIENT AQUEDUCT OF ALATRI. BY FATHER SECCH1*. 



The town of Alatri, of Pelasgic origin, famous for its encircling 

 walls of Cyclopean construction, is very ancient. Placed on the 

 summit of a calcareous mountain, it was altogether deprived of 

 water, and was separated from the nearest mountains by a valley, 

 about 125 metres in depth. According to a celebrated inscription, 

 the Censor L. Betilienus Varus conducted water to the town by 

 means of an aqueduct 340 feet high, and for this purpose he caused 

 arcades and strong pipes to be constructed : " fornices , fistulas solidas 

 fecit." The recent researches, made by the order of His Holiness 

 Pius IX., in order again to provide this important town with pota- 

 ble water, have led to the discovery of a large portion of the ancient 

 aqueduct. The levels which I have made show that the lowest 

 point of the aqueduct was 110 metres below the highest part of the 

 town ; this accords with the 340 feet mentioned in the inscription. 

 We have here, therefore, a water-conduit in the form of an inverted 

 siphon, under a pressure of 11 atmospheres, constructed 160 years 

 before our present era. It is difficult to say what quantity of water 

 was conducted ; but the dimensions of the aqueduct (the buttresses 

 of which measure 1 " 75 by 1'45 metre) show that it must have been 

 sufficient to supply the baths of the town, several public fountains, 

 and the whole of the town itself, now found to be traversed with 

 pipes of lead and terra cotta. Near the Acropolis, pipes of bronze 



* From a letter to M. Elie de Beaumont, published in the Comptes 

 Rendus-oi September 26, 1864. 



