1835.] Scientific Intelligence. 149 



10. „ 1607, observed by Kepler and Longoraontanus, Sept. 26. 



11. „ 1682, observed by Halley, who predicted its return in 1758. 



12. ,, 1758, returned as predicted, and discovered by Palitzch, 

 December 25. Observed by Messier and De L'Isle in January, 

 1 759. Arrived at its perihelion, March, 1 759. 



Mr. Twiss gave a short account of the papyri from Herculaneum 

 preserved in the Museum at Naples, and of the method of unrolling 

 them. 



They were first discovered in 1753, and are now deposited in the 

 Museo Borbonico. Being rolled up in scrolls, they have the appear- 

 ance of pieces of charcoal : and being piled up, it was only by acci- 

 dent that attention was directed to them, when Greek and Latin 

 characters were seen upon them. They are found reduced to a 

 scorched state, not more substantial than tinder. The difficulty of 

 unrolling them has been overcome by attaching to the back some 

 gold beater's skin by a strong gum : a small portion of this (when 

 fixed) is then gradually unrolled by bands attached to it, the scroll 

 resting in a semi-cylindrical trough lined with cotton. The process 

 can only go on at the rate of about one inch per day. Several 

 volumes have been restored and published. They appear to be chiefly 

 works of Epicurean philosophy. On the authority of one of them 

 the Economics of Aristotle is decidedly ascribed to Theophrastus. 

 The majority are Greek. One contains a review of the Iliad, in 

 which the heroes of Homer are considered as all allegorical. The 

 Latin works are on a differently prepared and thicker papyrus. The 

 name of the author never occurs till the end ; hence the impossibility 

 of ascertaining what they are till completely unrolled. 



Some remarks were made on the share which Sir H. Davy had in 

 suggesting the plan of unrolling, and conducting the whole research, 

 as described in his paper in the Philos. Trans. 1821. 



June \2lh. — An anonymous paper was read, entitled, '' A few 

 remarks on the theory of Volcanoes." 



The author's principal object in this paper is to support the theory 

 advanced by the late Dr. E. D. Clarke. 



Dr. Daubeny made some remarks on this paper, which he con- 

 sidered to accord with his own theory, as far as it goes. But it does 

 not proceed to account for ihe evolution of hydrogen, which he 

 explains by the action of water on the metallic bases of the earths. 

 The part of Dr. Clarke's view most open to doubt is the degree of 

 intensity of fusion, of which no sufficient evidence is adduced. 



Dr. Daubeny then referred to the subject of his own paper on the 

 absorption, &c. of plants. He had tried experiments in which plants 

 were deprived as much as possible of access to calcareous matter, in 

 which case the quantity of it found in their ashes was diminished, 

 but still some appeared. This might be derived from the water, or 

 even the atmosphere. He stated that when strontian was substituted 

 for lime, the same deficiency of calcareous matter was observed in 

 the plant, shewing that vegetables exercise a kind of selection as to 

 the earthy matter they secrete. 



Analogous experiments were mentioned on hens, who, when de- 



