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sea, emits clouds of ashes and pumice-dust. This dust is carried 

 by the winds as far as Mendoza, but these clouds do not strike 

 the town with the force of a San Juan zonda. The pumice- 

 dust is borne along by variable winds. From this fact we may 

 infer that the fine sand of the zondas comes from a similar source. 

 The most important question is, " Where originates the hot and 

 parching wind that always accompanies, and is peculiar to the 

 zondas ? " The old guides, who are familiar with the valleys of 

 the Andes, inform me that these winds blow from off the main 

 snow-clad ridge of that great chain of mountains, and express 

 their surprise at the fact, " that from a cold region comes a burn- 

 ing wind." 



Strong and steady winds generally follow a direct line. This 

 fact is peculiar to the zondas. If Miers's conjecture be true re- 

 garding the origin of these winds, the position of the volcano or 

 souffriere might be found by obsei'ving the following suggestion, 

 bearing in mind that the Mendoza wind comes from the north- 

 west, and the San Juan zonda from the west. That point where 

 two lines — one running west from the northern town, the other 

 northwest from the southern town — will intersect, is the starting- 

 point of the sand clouds, if not of the accompanying hot wind. 



Looking upon the map of South America, we find in the Cor- 

 dillera of the Andes, between the latitudes of San Juan and Men- 

 doza, four peaks marked as doubtful volcanoes, — Limari, directly 

 west of San Juan ; Chuapu, thirty miles further south ; and near 

 the half-way point of the two towns, Ligua. To the north of 

 west of Mendoza, stands prominent the lofty Aconcagua, that has 

 been estimated by two English captains to have an elevation of 

 23,900 feet. The point of intersection of the west and north- 

 west zonda lines is in the vicinity of Limari and Chuapu, and if 

 not either of these, the zonda volcano is a near neighbor to them. 



Mr. Sprague exhibited specimens of a fungus which 

 he had found upon young pear-trees, (Capnodium elong-a- 

 tum,) and which had been recently found in great quan- 

 tities on the stenns and leaves of young white pines grow- 

 ing in Hingham, by Mr. T. T. Bouve. He also exhibited 

 a drawing of the plant, showing the different forms of 

 the peridia, some being merely rounded half-spheres, 



