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Meteorological Ohservalory of Mount Vesuvhis. 259 



has, vvhen drank from a glass, an agreeable pungent taste of free car- 

 bonic acid — with no more of sulphuretted hydrogen than is pleasant. 

 It is perfectly clear In the glass and effervesces briskly. The escape 

 of gas does not appear to be confined to any particular part of the bed 

 of the lake, but takes place equally over all its surface. The grass 

 and reeds which grow luxuriantly at Its margin are constantly encrusted 

 with carbonate of lime from the water, and it is from this cause that 

 the area of the lake appears to have been contracted, and not from 

 any partial drainage which is evidently inexplicable since the level of 

 the lake is now only a few inches below that of the adjoining and level 

 Campagna. Breaking off a mass of grass and clods from the shore it was 

 found that the roots of the plants were also encased, while the stone walls 

 of the fields adjoining were wholly composed of loose blocks of trav- 

 ertine made up entirely of casts of the stems of growing grapes and 

 aquatic plants. It required but casual observation of the travertine in 

 other and distant parts of the Campagna to detect the same species of 

 plants imbedded in every part of its mass'. Blocks of travertine in the 

 Coliseum at Rome and other ancient buildings also showed us the 

 same evidence. A large space on the Campagna near the sulphur 

 I . lakes lately fell in, owing to the cavernous and unsupported nature of 



^ the rock, and it was easy to see in the freshly fractured portions of the 



rock the same stems of aquatic plants, such as now grow on the margin 

 of the water. 



It is perhaps too much to infer from these casual observations so 

 Wide a deduction as that all the travertine is due to this origin from sul- 

 phur waters charged with bicarbonate of lime ; but it is not going farther 

 than is allowed by a prudent philosophy to say that travertine is now 

 forming on the shores of Lake Solfatara from this cause. 



4. Meteorological Observatory of 3Iount Vesuvnis. 



The Meteorological Observatory recently erected at Mount Vesuvius 



was projected by Prof. Melloni, so well known to all the world by 



his memorable researches on heat, and the most distinguished of all 



the Italian physicists. The King of Naples gave the enlerprise his 



« sanction, and furnished the means to construct the building. The 



house is of ample dimensions, standing on an artificial terrace at the 

 summit of the hill of ashes which forms the limit of the arable region 

 of Vesuvius, and at an elevation of about 2000 feet. The centre has 

 three floors above the basement, and the two wings each one floor above 

 the basement; iu the rear and joining the main building is a round 

 tower, and the roofs are conveniently arranged for meteorological pur- 

 poses. All the plans were furnished by Prof. Melloni, who also super- 

 intended its erection, which by an inscription on the exterior appears to 

 have been begun in 1841. 



Unfortunately for science, the revolution of 1848 entirely arrested 

 tne farther progress of the undertaking; the house stands vacant, no 

 instruments are provided, and worst of all, Prof Melloni has been re- 

 J»oved, not only from his direction in the Observatory, but also from his 

 Professorship in the University, under ihe caprice of a despot who 

 Knows no law but his own will, and who has shown in this act that he 

 was unworthy of so noble a subject. 



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