The Ecclesiastical Calendar : its Theory and Construction. By Samuel
Butcher, D.D., late Bishop of Meath. (Hodge and Co., Dublin ; Macmillan, London.)—This learned work explains the principles on which the tables placed at the beginning of the Prayer-book for the finding of Easter, dm., are based. For the most part, the contents are of a technical kind, which would not interest the general reader, and which not all of those who are professionally interested in the subject would care to study. But there is something of general interest to be gleaned from it. We observe that the Bishop was strongly in favour of a Saari Easter, though he did not think that there was any hope of the change being made. We may quote the explanation of a difficulty which periodically occurs :—" The Lunar Tables, whether for the mean or true motion of the moon, are sufficiently accurate to make it possible that an astronomical Easter determined by the mean or true full moon should be kept on one Sunday in St. Paul's Cathedral, and in West- minster Abbey on the following Sunday ; for the difference of longitude between those two churches being about seven seconds (St. Paul's the more eastward), one Sunday morning begins at St. Paul's about seven seconds before it begins at the Abbey. Now suppose Eaater to be de- termined by the true full moon, and that on a Saturday evening at the Abbey the Paschal full moon happens at four seconds before midnight, then at St. Paul's it will happen three seconds after midnight on Sunday morning. The result will be that at the Abbey this Sunday will be Easter Day, while at St. Paul's the Paschal moon following on this Sunday, the next Sunday will be Easter Day."