1430. Barometer in spring. Towards the end of March, or more generally in the beginning of April, the barometer sinks very low with bad weather; after which it seldom falls lower than 29 degrees 5 minutes till the latter end of September or October, when the quicksilver falls again low with stormy winds, for then the winter constitution of the air takes place. From October to April, the great falls of the barometer are from 29 degrees 5 minutes to 28 degrees 5 minutes, and sometimes lower; whereas, during the summer constitution of the air, the quicksilver seldom falls lower than 29 degrees 5 minutes. It therefore follows that a fall of one tenth of an inch, during the summer, is as sure an indication of rain, as a fall of between two and three tenths is in the winter.