Croll was the first to suggest that cyclical changes in the shape of Earth's orbit, from elliptical (which is to say slightly oval) to nearly circular to elliptical again, might explain the onset and retreat of ice ages. No one had ever thought before to consider an astronomical explanation for variations in Earth's weather. Thanks almost entirely to Croll's persuasive theory, people in Britain began to become more responsive to the notion that at some former time parts of the Earth had been in the grip of ice. When his ingenuity and aptitude were recognized, Croll was given a job at the Geological Survey of Scotland and widely honored: he was made a fellow of the Royal Society in London and of the New York Academy of Science and given an honorary degree from the University of St. Andrews, among much else.

是克罗尔第一次提出，地球轨道从椭圆形（那就是说，有点呈卵形）到接近圆形，然后再回复到椭圆形的周期性变化，可能是导致冰川时代产生和消退的原因。在他之前，从未有人从天文学的角度对地球的天气变化作过解释。多亏克罗尔富有说服力的理沦，英国人开始接受关于地球上的有些地区在以前某个时期处于冰川控制的观点。克罗尔的杰出才能得到人们的普遍认可，他在苏格兰地质勘察局谋得了一个职位，还获得了许多荣誉：伦敦皇家学会及纽约科学学会吸纳他为会员，圣安德鲁断大学授予他荣誉学位，等等。

Unfortunately, just as Agassiz's theory was at last beginning to find converts in Europe, he was busy taking it into ever more exotic territory in America. He began to find evidence for glaciers practically everywhere he looked, including near the equator. Eventually he became convinced that ice had once covered the whole Earth, extinguishing all life, which God had then re-created. None of the evidence Agassiz cited supported such a view. Nonetheless, in his adopted country his stature grew and grew until he was regarded as only slightly below a deity. When he died in 1873 Harvard felt it necessary to appoint three professors to take his place.

遗憾的是，就在阿加西斯的理论终于在欧洲开始为人们所接受的时候，他却马不停蹄地在美洲一些人类从未涉足过的地方作野外考察。在他所到之处，包括赤道附近，他不断发现冰川的痕迹。最后，他确信冰川曾经覆盖过整个地球，毁灭了当时上帝已经创造的所有的生命。阿加西斯所引用的证据没有一个能够支持这种观点。尽管如此，在他所移居的美国，他的地位越来越高，直到成为仅次于神的一位圣者，以至于1873年，当他去世时，哈佛大学认为有必要增补三位教授才能顶替他所留下的空缺。

Yet, as sometimes happens, his theories fell swiftly out of fashion. Less than a decade after his death his successor in the chair of geology at Harvard wrote that the "so-called glacial epoch ... so popular a few years ago among glacial geologists may now be rejected without hesitation."

然而，阿加西斯的理论很快不再流行了。这种情况有时候是会发生的。在他去世后不到10年，接替他的哈佛大学地质系系主任这样写道：“所谓的冰河时代……几年前在研究冰川的地质学家中还很吃香，现在会教人们毫不犹豫地抛弃了。”