Radon concentration in groundwater was measured at 18 points including two continuous recording stations.
2
这是一台用于医药的打印式记录仪。
This is a printing recorder for medicine.
3
不论如何,沃尔夫查阅了欧洲各个天文台的所有记录,并把大约100年前的太阳黑子观测历史整理在一起。
Anyway, Wolf went though all records from various observatories in Europe and put together a history of sunspot observations going back about 100 years.