Four years later, also using a cloud chamber, he discovered the muon, again in cosmic rays.

四年后，同样使用云室， 他又在宇宙射线中发现了介子。

Back in the Cavendish Lab in Cambridge he built an artificial cloud chamber, a simple device in which he could cool and moisten the air, creating a reasonable model of a cloud in laboratory conditions.

回到剑桥大学的卡文迪许实验室以后，他建起了一个人工云室，一种简单的装置，他在里面可以冷却和湿润空气，在实验室现有的条件下创建一个说得过去的云层模型。

These might be anything from a field biologist's notes of lemming populations on Spitzbergen to a physicist's creation of muon tracks in a cloud chamber, or from a set of equations in the mathematical imagination to a vast computer model of the world's climate.

在这本书中你将会看到野外生物学家对于斯匹茨卑根群岛上的旅鼠种群的阐述，物理学家在云室里创建的μ介子轨迹，利用数学概念思考出的一组方程式，以及巨型计算机模型中的全球气候。