The Marquis of Salisbury possesses, at Hatfield, a fine library, which, like that of the Duke of Devonshire at Chatsworth, is rather the accumulation of centuries than the formation of any particular head of the house. Many of the oldest and rarest books were at one time the properties of either Lord Burghley, Sir Robert Cecil, or of some other distinguished member of the family. We may mention a few of the _incunabula_: Æneas Silvius, 'Epistolæ,' 1496; St. Augustine, 'De Civitate Dei,' 1477; a copy of the magnificently-printed edition of Aulus Gellius, 'Noctes Atticæ,' Jenson, 1477, a very rare work; Cicero, 'Ad Atticum,' 1470, also printed by Jenson; an example of the _editio princeps_ Homer, Florence, 1488; Juvenal, 'Satyræ,' 1474; the very rare second edition of Lactantius, 'Opera,' printed at Rome by Sweynheym and Parmartz, 1468; Livy, 'Historiarum Romanorum,' printed by Zarothus, 1480; Pomponius Mela, 'Cosmographia,' 1482; Ruffus, 'Opera,' 1472. Lord Salisbury's library includes several books which once belonged to Roger Ascham, notably a copy of Aristophanes, 'Comodiæ,' 1532; Aristotle, 'Opera,' 1531; Peter Martyr, 'Tractatio et Disputatio de Sacramento Eucharistiæ,' etc., 1549, one of the only two copies of which we have any record, the other example being in the Lambeth Library; and a large number of tracts of the time of Henry VIII. Of about 200 books which belonged to Sir Robert Cecil, we may mention two editions of Aristotle, 'Ethica,' 1572 and 1575; Baret, 'An Alvearie, or triple Dictionarie,' in English, Latin, and French, 1573; French Bible, 1546; Bodin, 'La Demonomanie des Sorciers,' 1580; Brache, 'Epistolarium Astronomicorum,' 1596; 'Astronomiæ Instauratæ,' 1602, and 'De Mundi Ætherei,' 1603; two editions of Cicero, 'Rhetorica,' 1552, 1562; Henning's 'Theatrum Genealogicum,' 1598; Galen, 'De Alimentis,' 1570; three editions of 'Natura Brevium,' one of 1566, and two of 1580; Ubaldino, 'Lo Stata Della Tre Corti,' 1594. The books of Lord Burghley include Aristotle, 'Ethica,' 1535; 'Opera,' 1539; 'Politica,' 1543; Ashley, 'Mariner's Mirror,' 1586; Basilius, 'Homiliæ,' 1528, and 'Opera,' 1551; Beda, 'Historia Ecclesiastica'; St. Chrysostom, 'Opera,' 1536; Cyrillus, 'Opera,' 1528; Demosthenes, 'Orationes,' 1528. The edition of Dioscorides, 'Opera,' 1529, belonged, respectively, to Lord Burghley and Sir John Cheke.