N the second century BCE, the Greek astronomer Ptolemy tried to explain the backward movement of the planets by using a solar system model that included . For centuries, this was the accepted model. During the Renaissance, Nicholas discovered the old heliocentric model of Aristarchus. In Aristarchus’s model, the rising and setting of the Sun was explained by the movement of the .

all persons entering into t

he employment of the compan

y, are considered as engaged

for twelve months, and those who leave

sooner, or do not comply with all these

regulations, will not be entitled

to a regular discharge.  

its main object was the establishment of "settlement houses" in poor urban areas, in which volunteer middle-class "settlement workers" would live, hoping to share knowledge and culture with, and alleviate the poverty of, their low-income neighbors.