ACROSS UNKNOWN SOUTH AMERICA 
when the rock now forming the mould was in semi-liquid 
form. Only once or twice did I notice hollows with a 
suggestion of spiral grooves in their walls; but I think 
that those had been caused at a more recent date by water 
flowing in and describing a spiral as it travelled downward 
in the interior of the vessels. 
On the hill where the observatory was situated, two 
circular volcanic vents were to be seen. The hill, which 
had a slope on one side, had evidently been split, as on 
reaching the top I found that an almost vertical precipice 
was on the other side. Quantities of quartz and crystals 
were to be found on that hill. All over that region 
quaintly-shaped rocks were also to be found, some like 
small cubic or rectangular boxes, others not unlike ink- 
stands, others in hollowed cylinders or spheres. Many, 
and those were the quaintest of all, were of a rectangular 
shape, which, when split, disclosed a rectangular hollow 
inside. These natural boxes were mostly of iron rock, 
laminated, which had evidently collected when in a liquid 
state round some soft matter, that had subsequently 
evaporated or disappeared with the intense heat, leaving 
empty spaces inside. The laminations were about one 
eighth of an inch thick. 
Padre Colbacchini told me that some distance off a 
curious pool of water existed which he called the “ electric 
spring.” When you placed your hand in it you received 
a slight electric shock, while an impression similar to that 
of an electric current continued to be felt as long as you 
kept your hand in the water. 
The mission buildings at Tachos were at an elevation of 
1,600 feet, the observatory, 100 feet higher. The tempera¬ 
ture on May twenty-third was maximum 81 °, minimum 
68 . 4 ° Fahrenheit. From the observatory hill an uncom¬ 
mon sight was before us. Seven large and small, isolated, 
conical and domed hills stood in perfect alignment from 
north-northeast to south-southwest in two different sets. 
248 
