Mr James Straton on the Raiti-Gauge. 43 



the mystery, " When there is no wind it (the gauge) is very 

 near the truth ; the more wind the farther from the truth." 

 Yes ; I have stood by the gauges in rain and in snow, in 

 calm and in storm, and seen the truth of the statement de- 

 monstrated many, many times. Indeed, all are familiar with 

 facts which demonstrate the proposition, though they may 

 not have drawn the important inference from what they saw. 

 When we witness the action of the driving gale, as, loaded 

 with the feathery flakes, it sweeps over the crested ridge of 

 the bank or wave of snow, we see the particles just when 

 they pass the crest, make a somersault, as it were, and fly off, 

 over the adjoining wall, some ten or twelve feet high, per- 

 hapsto some distance, where theyfall,and form a second bank. 

 We see also that the lee or lithe side of the bank is generally 

 scooped out in a kind of circular hollow, beyond which 

 the ground is for some distance cleared of snow. (Plate I., 

 D and I, fig. 1.) Now, the mouth or orifice of the receiver 

 is always in the lee-side of the run or lip, on passing over 

 which the wind, when strong enough, makes a whirl, and away 

 it flies over the opposite lip, carrying the particles of rain or 

 snow with it. It is in such circumstances that the efficiency 

 of gauges is put to the severest test. If they fail, they are 

 worthless ; and the most ample, elaborate, and expensive 

 instruments I have seen do fail in such circumstances. All 

 the " eye-traps or gimcracks, usually set up as rain-gauges" 

 as Dr Fleming expresses it, are worthless, yea, worse than 

 worthless, because they mislead, compared with a plain piece 

 of tube an inch or two wide, by three or four long, which 

 may be purchased in any town for a penny or two. 



The one, two, and three inches diameter gauges, particularly 

 the first and second, always register the most uniformly and 

 the greatest quantity, not a trifling or unimportant quantity, 

 but to the almost incredible extent of a third and a fourth 

 part more than the large gauges, during gales of wind. Now, 

 I can only account for this by the fact, which I have often 

 observed, that in small or narrow openings the wind does not 

 form a whirl sufficiently powerful, excepting perhaps in some 

 extremely rare instances, to carry the particles of rain or 

 snow out of the small, and away as it does out of the larger 



