I have (saith he) sometimes thought upon the _Changes_, which 'tis likely, the supposed Inhabitants of the _Moon_ might discover in our _Earth_, to see, whither reciprocally I could observe any such in the _Moon_. For example, methinks, that the _Earth_ would to the people of the _Moon_ appear to have a different face in the several seasons of the year; and to have another appearance in _Winter_, when there is almost nothing green in a very great part of the _Earth_; when there are Countries all covered with snow, others, all covered with water, others, all obscured with Clouds, and that for many weeks together: _Another_ in _Spring_, when the Forrests and Fields are green. _Another_ in _Summer_, when whole Fields are yellow &c. Me thinks, I say, that _these_ changes are considerable enough in the force of the reflexions of Light to be observed, since we see so many differences of Lights in the _Moon_. We have _Rivers_ considerable enough to be seen, and they enter far enough {121} into the Land, and have a bredth capable to be observed. There are _Fluxes_ in certain places, that reach into large Countries, enough to make there some apparent change; & in some of our Seas there float sometimes such bulky masses of Ice, that are far greater, than the Objects, which we are assured, we can see in the _Moon_. Again, we cut down whole Forrests, and drain Marishes, of an extent large enough to cause a notable alteration: And men have made such works, as have produced Changes great enough to be perceived. In many places also are _Vulcans_, that seem big enough to be distinguish't, especially in the shadow: And when Fire lights upon Forrests of great extent, or upon Towns, it can hardly be doubted, but these Luminous Objects would appear either in an Ecclipse of the Earth, or when such parts of the Earth are not illuminated by the Sun. But yet, I know no man, who hath observed such things in the _Moon_; and one may be rationally assured that no _Vulcans_ are there, or that none of them burn at this time. This it is (_so he goes on_) which all Curious men, that have good _Telescopes_, ought well to attend; and I doubt not; but, if we had a very particular _Map_ of the _Moon_, as I had designed to make one with a _Topography_, as it were, of all the considerable places therein, that We or our Posterity would find some changes in Her. And if the _Mapps_ of the _Moon_ of _Hevelius_, _Divini_, and _Riccioli_ are exact, I can say, that I have seen there some places considerable enough, where _they_ put _parts that are clear_, whereas _I_ there see _dark ones_. 'Tis true that if there be _Seas_ in the _Moon_, it can hardly fall out otherwise, than it doth upon our _Earth_, where _Alluvium's_ are made in some places, and the Sea gains upon the Land in others. _I say_, if those Spots we see in the _Moon_, are Seas, as most believe them to be; whereas I have many reasons, that make me doubt, whether they be so; of which I shall speak elsewhere.