250 



SCIENCE. 



[Vol. IX., No. 214 



dense them from a recent parliamentary paper 

 which shows the extent of acreage, and the esti- 

 mated average produce per acre, of the principal 

 crops of the United Kingdom for 1886. The esti- 

 mate is based on returns received from about 

 14,000 parishes. 



The figures show that during the year, England 

 produced a wheat-crop of 58,071,171 bushels, 

 which shows the large faUing-off of 15,950,077 

 bushels, or more than 21 per cent on the year 1885, 

 at an estimated average in 1886 of 26.87 bushels an 

 acre, against 31.51 bushels in the year before. The 

 falling-oflf from the average yield of an acre ap- 

 pears in all the counties of England except four. 

 For Wales the estimated total produce of wheat 

 amounted to 1,501,075 bushels, at an average rate 

 of 21.86 bushels an acre, being .83 of a bushel 

 above the estimated normal average. For Scotland 

 the total produce of wheat is shown to be 1,895.- 

 652 bushels, at an average rate of 33.77 an acre, 

 which may be compared with an average of 84.33 

 in 1885. The year's average, though smaller than 

 the previous year's, is larger by nearly a bushel 

 than the ordinary average. The aggregate results 

 for wheat in Great Britain thus amount to 61,467,- 

 898 bushels, as compared with 77,587,666 in the 

 preceding year, while the acreage under wheat 

 was 7.8 per cent below that of 1885. Ireland also 

 shows a diminution in the production of wheat, 

 the numbers of bushels being 1,879,987 as against 

 2,048,103, a decrease of 8.21 per cent. 



Of barley, the United Kingdom produced 78,- 

 309,607 bushels, as against 85,721,632 in 1885, and 

 this decrease of 8.65 per cent is shared by all parts 

 of the kingdom. The return for oats is more 

 favorable, as the production of the whole king- 

 dom was 169,876,088 bushels, an increase of 5.57 

 per cent over 160,440,907 bushels, the yield of the 

 preceding year. In this crop Wales is the only 

 portion of the kingdom where there is a decrease, 

 and that is very small. 



The pulse-crops are again a partial failure in 

 many counties, and the production of beans and 

 peas shows unsatisfactory results when compared 

 with the normal rate of yield. The numbers for 

 the whole kingdom, however, show an advance on 

 those of 1885, being, for beans, 10,307,187 bushels, 

 an increase of 15 per cent ; for peas, 5,855,382, an 

 increase of 85 per cent. 



Of the root-crops, potatoes show a decrease 

 from 6,374,242 tons to 5,835,487, a faUing-off of 

 8.45 per cent ; and of this, Ireland bears more 

 than her share, as the returns from that country 

 fell off 16 per cent. Wales and Scotland, on the 

 other hand, are a little above the average. Tur- 

 nips show an improvement in all the four divis- 

 ions of the kingdom, having risen from 24,062,- 



608 tons to 33,957,415, which means an increase of 

 over 41 per cent. Mangold, again, shows nearly 

 as large an increase, from 5,969,523 tons to 7,788,- 

 811 tons, which is over 30 per cent. 



The hay-crop from grass grown on permanent 

 pasture-land is shown to exceed slightly the aver- 

 age yield an acre in Great Britain, the total prod- 

 uce amounting to 5,763,285 tons, while that from 

 clover is at the normal average of 3,311,449 tons, 

 the total produce of both descriptions thus show- 

 ing an aggregate of 9,074,684 tons. Hops show a 

 decided gain in the year, as the yield in 1886 was 

 776,144 hundred weight as against 509,170 hundred- 

 weight in 1885, or an increase of over 52 per cent. 



The tables show, that, on comparing the figures 

 for 1886 in Great Britain relating to the produce 

 of the crops dealt with, mangold, hops, and hay 

 are the only ones showing an increase on the es- 

 timated ordinary average yield. Corn and pulse 

 crops, potatoes, and turnips all show a decrease 

 on the average, though in some cases they are in 

 advance of the previous year. The returns for 

 Ireland sliow a decrease, on the average, of wheat, 

 barley, beans, and potatoes, and an increase of 

 oats, peas, turnips, mangold, and hay. 



NATURAL GAS. 



In a paper on the pressure and composition of 

 natural gas, read before the Engineers' club of 

 Philadelphia, Dr. H, M, Chance stated that there 

 are no records of the gas-pressure first shown by 

 the larger wells The recorded pressures were 

 nearly all observed after the gas had been blowing 

 off for some weeks, months, or even years ; and 

 the pressure then shown by a gauge is evidently 

 no measure of the pressure under which the gas 

 exists in the rock, for the gas soon becomes ex- 

 hausted from the immediate vicinity of the well, 

 which then draws its supply from a considerable 

 distance, and perhaps through bands of rock of 

 such texture — and perhaps even through the clay 

 filling of crevices — that the pressure shown at the 

 well may be only a fraction of the actual pressure. 



Hence, while recorded pressures range from 

 about 600 down to 200 pounds per square inch, 

 there is every reason to believe that the actual 

 pressures are perhaps from 500 to 1,000 pounds 

 per square inch, or even in some cases much 

 greater, but still being less than the maximum as 

 limited by depth. This maximum is very much 

 less than the pressure necessary to effect liquefac- 

 tion, and the supposition that the gas exists as a 

 liquid must therefore be abandoned. 



One of the most interesting phenomena recently 

 observed in natural gas is its variability. The an- 

 alyses of Professor Sadtler, made some nine years 



