920 kKEPORT-—1890. 
period, especially in the early years of the sixteenth century. And this brings us 
to the important point, viz. that the agrarian changes were facilitated by the law 
of customary tenure ; which but slowly recognised, or, at any rate, provided means 
for enforcing, the right of the customary tenants to undisturbed: and hereditary 
possession. The law as it appears towards the end of the period in Coke is very 
probably itself the outgrowth of the policy of the government, and of public 
opinion, in relation to the action of the lords of land, and does not represent the 
older law. ‘This seems to be shown, among other arguments, by the history of the 
celebrated clause in the later editions of Littleton, as to the judgment of Chief 
Justice Brian, and by a comparison with legal doctrine in other countries, e.y., in 
North Germany, where the conditions were in several respects similar. The views 
which have of late years been taken of the history of land-tenure in the Middle 
a\ges, have been unduly coloured by the assumption that the manor grew out of a 
free community, and that the lord’s legal rights were all encroachments. It would 
seem more likely that the legal right of the lord to dispossess his villeins is very 
ancient ; that it was exercised most sparingly for centuries merely because it was 
rarely profitable; that as soon as it became profitable it was exercised; and that 
it was not taken away until it had had great practical consequences. 
A similar point is illustrated by the development of the law as to fines on 
succession. It is probable also that in many cases the way was prepared for the 
removal of customary tenants by the substitution of leases for copyhold. 
The extent of the revolution can only be exactly estimated when due regard 
has been paid to each of the possible directions in which change could be effected. 
All that can be here attempted is to take the most important of the innovations 
tke enclosure of the open arable fields—and discover the area affected. ‘This can 
be done to some extent upon the evidence of contemporary writers: thus there is 
a concurrence of authorities that Essex and Kent were pretty completely enclosed 
(in this sense). But the vague declamations of the pamphleteers of the period 
need examination, e.g.,in the case of Oxfordshire; and even such a fact as the 
rising in Norfolk does not bear the interpretation which it might seem natural to 
put upon it. A more satisfactory basis for an estimate is to be found in the infor- 
mation given in the Reports to the Board of Agriculture, in Arthur Young’s 
Tours, and in Enclosure Acts, as to the extent to which common-fields still sur- 
vived in 1750. 
&. The Element of Chance in Examinations. 
By Professor F. Y. Epcnworru, D.C.L. 
This paper is a sequel to the paper on the Statistics of Examinations which 
was read before the British Association in 1888, and was published in the ‘ Journal 
of the Statistical Society’ for the same year. In that paper it was shown that the 
discrepancies hetween examiners marking the same work are subject to the laws of 
error which govern the differences between observations relating to the same 
physical quantity. This theory is now exemplified by a variety of statistics, It is 
shown that the following questions can be answered with some precision when the . 
requisite data are available: At a given examination how many of the successful 
candidates are quite safe—in this sense, that the chance is yery small (say 1 in 
100) that any assigned one of them would have come out unsuccessful if the 
work had been appraised by a different examiner or set of examiners? Of such 
displacements, what is the most probable number under given circumstances? The 
answer to the first question varies from a third to two-thirds of the successful can- 
didates. In answer to the second question it is found that the number most likely 
to he displaced by a change in the personnel of the examiners is sometimes a 
seventh part of the number of the successful, sometimes less. It is shown that the 
method of eliminating chance by manipulating the marks after they have left the 
examiner's hands is often precarious and ineffective. Other methods of alleviating 
the evil are considered. 
