| OCR Text |
Show 162 WEIGHT OF EARTH CnAr>. TIL castings were dried (excepting in one specified instance) by exposure during many days to the sun or before a hot fire. WEIGHT OF TilE CASTINGS ACCUMULATED AT TilE MOU'l'll oF A SINGLE Bunnow. (1.) Down, Kent (sub-soilred clay, fullo~flints, ?vor-~ lying the chalk). rrhe largest casimg whlch l could find on the flanks of a steep valley, tho sub-soil being hero shallow. ln this one case, tho casLinO' was not well dried .. .. .. .. (2.) Do~n.-Largestcastingwhich I could tinc1 (con-} sisting chiefly of calcareous matter), O?- extremely poor pasture land at the bottom of tho valley mentioned under (1.) .. .. .. . ·· (3.) Down.-A large casting, but not of u~usnal Slz.e, t from a nearly level field, poor pasture, la1d dowu m f grass about 35 years before.. . . . . . · · (4.) Down.-Average weight of 11 not large castmrrs} ejected on a sloping surface .on my lawn? after they had suffered some loss of wmg~t [rom ben1:g exposed durin()' a considerable length ol tnne to ram .. (5.) Ne~r Nice in France.-~verage weight of 121 castings of ordin. ary dimenswns, collected by Dr. Kinrr on land which bad not been mown for a long tim~ and where worms abounded, viz., a lawn protected by shrubberies, near tho sea; soil sa~dy and~ calcareouR; these castings had been exposed 1or some I time to rain, before being collected, and must .have] lost some wei~ht by disintegration, but tbey sL1ll re-tained their form . . . . . . . . . · (6.) The heaviest of the above twelve casiinrrs .. (7.) Lower BengaL-Average weight of 22 castings,~ collected by Mr. J. Scott, and stated by him to. have been thrown up in the course of one or two mghts (8.) The ~~aviest of. the above .22 castings . . . . . (9.) Nilgm Mount~~ms, S. India; avorag~. w01g~1~ of} the '5 largest castmgs collected by Dr. h.1ng. lhoy had been exposed to the rain of the last monsoon, and must have lost some weight .. .. . .. (10.) Tho heavir:st of tho above 5 castings .. Ounces. 3•08 2·0U In this table we see that castings which had CuAr. Ill. BIWUGITT UP BY ·woRMS. 163 been ejected at the mouth of the same burrow, and which in most cases appeared fresh and always retained their vermiform configuration, generally exceeded an ounce in weight after being dried, and sometimes nearly equalled a quarter ·of a pound. On the Nilgiri mountains one casting even exceeded this latter weight. The largest castings in England were found on extremely poor pasture-land; and the e, as far as I have seen, are generally larger than those on land producing a rich vegetation. It would appear that worms have to swallow a greater amount of earth on poor than on rich land, in order to obtain sufficient nutriment. With respect to the tower-like castings near Nice (Nos. 5 and 6 in the above table), Dr. I(ing often found five or six of them on a square foot of surface; and these, judging from their average weight, would have weighed together 7 ~ ounces; so that the weight of those on a square yard would have been 4lb. 3! oz. Dr. King collected, near tho close of the year 1872, all the castings which still retained their vermiform shape, whether broken down or not, from a M 2 |
