298 HISTORY OF ASTRONOMY. 



was devoted to hourly observations. The magnetical 

 observations occupied nearly four hours of two and 

 sometimes three persons on three days of each month, 

 when all the elements necessary for determining the 

 direction and the total force of the earth's magnetism 

 were carefully observed. 



A minute record was preserved of all the earthquakes 

 experienced during the continuance of Lieutenant Gilliss 

 in Chili. The number of shocks recorded was 125 in 

 34 months, being an average of about one each week. 

 A seismometer was erected, but it was not sufficiently 

 sensitive, and generally made tLo record of the agitations 

 of the earth's crust. 



Congress liberally ordered the publication of the re- 

 sults of this expedition, directing that the whole work 

 should be well printed on good paper of quarto size, and 

 well bound. The results will be comprised in seven 

 volumes, of which the first two have already been pub- 

 lished. Yol. I. contains a full account of Chili, its 

 geography, climate, earthquakes, government, social 

 condition, mineral and agricultural resources, commerce, 

 etc., with a narrative of the general progress of the 

 expedition. Vol. II. contains Lieutenant MacKea's nar- 

 rative of his magnetical expedition across the Andes and 

 pampas of Buenos Ayres, with an account of the 

 minerals and mineral waters of Chili, their Indian anti- 

 quities, and a description of various mammals, birds, 

 reptiles, fishes, Crustacea, and plants collected by the ex- 

 pedition. Yol. III. will contain the differential observa- 



