200 report — 1865. 



anything with them. After consulting the observers, each of whom was 

 asked to send in his or her definition of a rainy day, the plan I recommended 

 was to count as a day of rain every one on which O01 inch fell. How this 

 will work remains to be seen ; but it is certainly a step in the right direction — 

 that is to say, towards uniformity. 



Another point noticed at an early period was the unequal geographical 

 distribution of the stations, some parts of the country being amply provided, 

 while in others the gauges were fifty or sixty miles apart. Thanks to the 

 ,£55 granted by this Association, this state of things no longer exists ; how it 

 has been removed may be learnt from my previous Reports, or from the 

 accompanying Map. Of course there are still great inequalities, but they are 

 as nothing compared with what existed in 1859. 



It remains to notice the series of experimental gauges which have been 

 recently started to settle various disputed points. Reference has already been 

 made to the decreased amount of rain caught in gauges placed on high build- 

 ings, and to the experiments of Dr. Heberden and Professor Phillips on the 

 subject. On finding that (owing to the previous absence of any rainfall 

 centre, if I may so term myself) the gauges throughout the kingdom were 

 at all sorts of elevations, from 90 feet downwards, it was evident that 

 some means must be devised for correcting these observations and redu- 

 cing them to what they would be if made at one uniform level. Many of 

 the gauges being elevated on pillars or pedestals, it was urged, and with 

 apparent reason, that as all previous elevation experiments had been made 

 upon, and in the vicinity of, buildings, the laws of decrease deduced there- 

 from were not, or at any rate might not, be applicable to gauges mounted 

 as above described. In order to test this point, Colonel Ward, of Calne, 

 kindly undertook the cost and trouble of mounting a set of gauges on part 

 of his lawn, a description of which I read to this Section at the Newcastle 

 Meeting ; they are now eleven in number, and at heights varying from level 

 with the ground to 20 feet above it. In order to check the applicability of 

 the Cable results to other localities, a similar but less extensive set of gauges 

 lias been established near Manchester by the Rev. J. Chadwick Bates. 



It was rather singular that, although, as before stated, rainfall has been 

 measured in this country nearly two hundred years, there had been prior to 

 1860 no published experiments on a comprehensive scale to determine the 

 best size and form of gauge. It would be inappropriate here to enlarge to 

 any extent upon the various theories put forth upon the subject ; and I will 

 only remark that the gauges principally issued by the Scottish Meteoro- 

 logical Society are but 2 or 3 inches in diameter, while a high Scottish 

 authority '•' has no faith " in anything less than a foot in diameter. Mr. 

 Olaisher's gauges, everybody knows, are 8 inches in diameter, Luke How- 

 ard's 5 inches, and the Royal Engineers' are 1 foot square. An exhaustive 

 set of experiments have therefore been undertaken on this point also, by 

 Col. Ward and Mr. Bates, the gauges varying from 1 inch to 2 feet in dia- 

 meter — square gauges, turf-gauges, snow-gauges, &c, being also tried. Col. 

 Ward has altogether 29 gauges at work ; and Mr. Bates has, I believe, 13, 

 beside the thermo-rain-gauge mentioned below. 



Reference was made in the earlier part of this Report to the peculiarly 

 heavy rainfall in mountainous districts, which had been carefully observed in 

 Cumberland during the years 1844 to 1853. It was felt that it would be 

 very interesting to ascertain if similar physical configuration received similar 

 fall in other parts of the country, and that the district round Snowdon 

 appeared very suitable for the experiments. Favoured by the assistance of my 

 friend Mr. Rogers Field, of Hampstead, and that of Captain Mathew, of Wern, 



