Mr James Straton on the Rain-Gauge. 47 



gauge, even the most perfect, registers too litle rain, because 

 the quantity required to wet the inside of the receiver is 

 dried up, evaporated between showers three or four hundred 

 times every year. Now, water passes off glass very much as 

 it does from a cabbage leaf or a duck's back, so that the loss 

 from evaporation is reduced to the least quantity. (4.) The 

 strength is ample for every purpose of fair wear. The glass 

 gauge is as safe as our windows — much more safe than our 

 roof-lights, our cupolas, our greenhouses, and conservato- 

 ries. A heavy knock, or severe frost, is destruction to the 

 copper and iron gauge as certainly as the glass. In the form 

 of gauge which I propose, the risk from frost (the implacable 

 enemy of the rain-gauge, as I have said) is avoided by the 

 position of the cistern in the ground. Lastly, Glass is not 

 liable to rust and corrode like iron by constant exposure in all 

 weathers ; it requires neither paint nor varnish at any time, 

 and, except broken by accident, it continues sound and effi- 

 cient from age to age. 



The gauge I refer to (fig. 2) may be described as a small 

 bottle turned upside down, and the bottom cut off. The body 

 of the bottle forms the receiver A, one and a half inches 

 wide by six deep ; the neck, extended to 30 inches long by 

 f wide, forms the cistern B, on which the scale is engraved, 

 and the instrument is complete. The quantity of water 

 which would fill one inch of the receiver fills about five inches 

 of the cistern ; consequently, each inch of the scale is about 

 five inches, and each tenth about half an inch long. The 

 tenth may be easily subdivided into five or ten parts, and the 

 readings taken to the hundredth part of an inch. A frame, 

 C, formed of four slips of oak deal, is firmly planted in the 

 ground ; into this frame the gauge is passed down easily, but 

 without room to shake, and the whole is ready for use. The 

 line D represents the level of the ground, above which the 

 mouth of the receiver should be 15 or 16 inches elevated, and 

 quite level. The observer can draw up the gauge at any 

 moment, read the depth of water, empty it as often as he 

 thinks proper, and replace the gauge in its position. 



This, the most accurate and efficient form and size of the 

 rain-gauge — an instrument so essential to science and the 



