kept constantly resolving, promising, even vowing to refuse Jesus nothing that He asked, to bear every little pain and inconvenience without relief, to give himself no gratification whatsoever at meals, even when not well or on feasts, and to increase his corporal penances. 'You must be your own executioner I want from you a suffering love,' were the words which Father Doyle says he heard spoken clearly and forcibly in his soul as he knelt one night in 1913 before the tabernacle. His intense desire for suffering led Father Doyle at times to practise mortifications which-to apply Mr. O'Rahilly's comments to the particular case-it would be hard to justify on general principles. Sometimes the mortifications merit to be called foolish or whimsical; sometimes they deserve to be more strongly condemned as unwise and exaggerated. Standing up to the neck in a pond at 3 o'clock on a freezing winter's morn; taking the discipline with a heavy chain; rolling in furze, and walking through nettles till the whole body was one big blister, smarting and stinging-these are rightly included in a section headed Holy Follies.' Mr. O'Rahilly, by quotations and examples, repeatedly helps us to place these incidents in their true spiritual perspective.

Father Doyle effectively concealed his spirit of mortification under a bright and genial manner and an unwearying activity. In social circles he was recognized as the type of a perfect gentleman and cultured priest; on missions he was an enthusiastic and successful worker; with nuns he was a favourite for retreats, for confession and for direction.

In 1914 he offered himself to be a Military Chaplain. 'I long to go and shed my blood for Jesus, and if He wills it, to die a martyr of charity,' he remarks in his private diary. A year later, in November, 1915, he received his appointment from the War Office. The story of his one-and-a-half years at the Front is told in a series of beautiful letters, chiefly to his father, supplemented by some notes and jottings. To abbreviate the account would but spoil it. Suffice it to say that Father Doyle spared no toil and shirked no danger; that he was beloved for his gaiety and revered for his piety; and that when he was numbered among the slain, private soldier and general, Catholic and Orangeman, bore tribute to his heroism and their loss.

In this biography Mr. O'Rahilly has given us a new evidence of his own literary versatility. And, however opinions may differ on other points, there are few, if any, who will not agree that Father Doyle's life, as it now stands revealed to us, was a marvellous one, paralleled only by the lives of the great ascetics of by-gone days.

D.

THE ENGLISH CATHOLICS IN THE REIGN OF QUEEN ELIZABETH. By John Hungerford Pollen, S.J. 1558-1580. London: Longmans, Green & Co.

THE task which Father Pollen proposes to himself in this volume is to describe the history of English Catholicism as a whole from the accession of Elizabeth till the rise of the counter-Reformation about

twenty years later. This is a work which was very much needed, for though the events of the period have been frequently treated of by Protestant writers, Catholic books, so far, are merely accounts of individual efforts on behalf of the old religion, or biographies of martyrs, confessors, or other notable persons belonging to the ancient faith. The author of the present volume points out that the publication in recent years of many series of documents bearing on the religious changes under Elizabeth makes it possible at present to discuss the history of the Catholics with some approach to completeness. The State Papers of England and Spain, in part now accessible, and other materials of various kinds have been utilized by Father Pollen, and his book runs to about four hundred pages, embracing, besides its nine chapters, an account of his main sources, abundant references to authorities, and a full and carefully compiled index.

There are two points that strike one at once at the outset of the re-establishment of Protestantism as the religion of England. The first is the extraordinary hypocrisy and double-dealing displayed by the Queen before and immediately after her accession. The second is the suddenness with which the Church re-organized by Mary collapsed before the onslaught of the Protestant party. A few days before Queen Mary died she recognized Elizabeth as her heir on condition that she should maintain religion as she (Mary) had restored it.' In January, 1559, Elizabeth was crowned by the Bishop of Carlisle, and swore at the ceremony to preserve to him and the churches committed to his care all canonical privileges and due law and justice,' and to protect and defend him, 'as every good king in his kingdom ought to be protector and defender of the bishops and churches under their government.' Before the year was out the Bishop of Carlisle, and all the remaining Bishops in England were deprived of their sees, and many of them imprisoned, the Acts of Supremacy and Uniformity having been passed in the meantime in both Houses of Parliament and confirmed by the Queen's assent. The other remarkable circumstance connected with the re-introduction of Protestantism must always remain a reproach to English Catholicism. Indeed, Protestants, no less than Catholics, says Father Pollen, must feel ashamed of the 'immediate surrender' of the clergy and the laity. The Bishops were the only party to make even the appearance of a fight at this stage. Various reasons are put forward to explain or account for the almost total defection of the clergy, but when everything is said, it still is extraordinary that the great majority of the English priests accepted the Acts of Supremacy and Uniformity without a struggle, while, as for the laity, Jewel wrote at the time that the ranks of the papists have fallen almost of their own accord.' To the credit of Ireland it should be remembered that such things did not happen there. Bagwell, a strong Protestant, admits that 'a Primate not acknowledged at Rome had small chance of reverence from the Irish masses' (Ireland under the Tudors, v. ii. p. 356), and other authorities might be quoted to the same effect.

L..

The fortunes of the Catholics in England went from bad to worse

for nearly fifteen years of the Queen's reign. Various efforts were made in the beginning to restore friendly relations between Popes Paul IV and Pius IV and the English Court. They were of no avail. Then came the landing of Mary, Queen of Scots, the rising in her favour in the North, the sentence of excommunication and of deposition against Elizabeth. These events led to increased severity in the operation of the laws against the Catholics, who were believed to be in sympathy with the partisans of the executed queen. These matters are ably described in the first half of the volume under notice. The remaining chapters deal in the main with the improvement in the condition of Catholicism which may be said to have synchronized with the growing influence of the Douay Seminary, founded as far back as 1568 by Dr. William Allen. Here some English exiles congregated to study for the priesthood, and in 1574 the first of them made his way to England to labour in the mission field. The English College in Rome, established a few years later, soon commenced to send home zealous men to work, and in the case of some of them, to suffer for the old religion.

Father Pollen's work carries the story of the Catholic struggles down to the year 1580, when the Jesuit Father Persons and others arrived from Rome. For the period embraced in the volume, it is likely to become the standard work of reference. The author has given many years' study to his subject, and he has pieced together from a vast variety of sources a most interesting narrative. His best recompense would be that the fruits of his labour should become known to all students of Catholic history, and we wish his volume the success it undoubtedly deserves.

PAUL WALSH.

BOOKS, ETC., RECEIVED

America: A Catholic Review (April).

The Ecclesiastical Review (April).

U.S.A.

The Rosary Magazine (April). Somerset, Ohio.

The Catholic World (April). New York.

The Austral Light (March).

The Ave Maria (March).

The Irish Monthly (April).

Melbourne.

Notre Dame, Indiana.

Dublin: M. H. Gill & Son, Ltd.

The Catholic Bulletin (April). Dublin: M. H. Gill & Son, Ltd.
The Month (April). London: Longmans.

Études (April). Paris: 12 Rue Oudinot (VIIe).

Revue Pratique d'Apologétique (April). Paris: Beauchesne.

Revue du Clergé Français (April). Paris: Letouzey et Ané.
The Fortnightly Review (April). St. Louis, Mo.

The Lamp (April). Garrison, N.Y.

Revue des Jeunes (April). Paris: 3 Rue de Luynes.

The Homiletic Monthly (April). London: Burns & Oates.

THE PRINCIPLE OF RELATIVITY AND EINSTEIN'S LAW OF GRAVITATION

BY REV. PATRICK J. BROWNE, M.A., D.Sc.

THERE are three periods in the history of physical theory which we must consider in order to arrive in logical sequence at the Law of Gravitation formulated by Einstein in 1915. The first is that previous to the famous experiment of Michelson and Morley in 1887; the second goes from the time of that experiment to the announcement by Einstein, in 1905, of what is now known as the restricted Principle of Relativity; the third lies between that date and 1915, when Einstein advanced a further Principle of Relativity, containing what he called a Principle of Equivalence and a Law of Gravitation differing from Newton's and dispensing altogether with the notion of attraction at a distance.

It is well to state at the outset that the Principle of Relativity, though coupled in the minds of some of its adherents with philosophic idealism, by no means involves such idealism. Those complete Relativists hold that we can know nothing but phenomena, and that all our Physics is merely a statement of the inter-relations of such phenomena. But we can believe in the real existence of matter, motion, and time, and the Principle of Relativity only commits us to holding that we cannot measure quantity in those things absolutely, because we are entirely dependent for such measures on our foot or metre rules and our clocks, and any universal law of change in the dimensions or rates of these instruments would for ever escape us. But, though we may not discover the absolute changes of our measures of space and mass and time, we may find a relation or relations between them which will fit in with the results of experiment. A Principle of Relativity was inherent in all the science of dynamics for a long time known as Newtonian, Newton being the first to formulate clearly, and to develop to a large extent, the three celebrated Laws (or rather axioms) on which it depends. The science treats of the molar motions of

FIFTH SERIES. VOL. XV-JUNE, 1920

bodies under the action of forces, and its axioms are (a) that every body, if undisturbed, remains in a state of rest or uniform motion in a straight line; (b) that the rate of change of motion in any direction is proportional to the force in that direction; and (c) that to every action there is an equal and opposite re-action. Now these laws allow us to discover only the motion of bodies relative to one another; the whole framework of any system of bodies we are treating might (along with ourselves) receive a uniform motion in any direction without our becoming conscious thereof. There is no use objecting that we might know it by noting the change of our position relative to the sun, or a fixed star, because we do not know if those bodies are really fixed; their absolute motion is unknown to us, and Newtonian dynamics gives us no means of finding it. The principal force in Newtonian dynamics, gravitation, was an attraction in a straight line between two bodies, proportional to the product of their masses divided by the square of the distance between them. It merely depended on relative position, by no means on velocity. Though it raised the enormous philosophic difficulty of action at a distance, it gave an excellent account of the behaviour of the celestial bodies. But it could not solve the problem of finding the absolute velocity of any one of them. Paradoxically enough, there is one part of the motion of bodies which dynamics can determine absolutely and uniquely, their rotation. There is a definite axis, and no other, through the centre of gravity of a body about which it rotates, and the amount of that rotation is also definite.

Let us turn now from dynamics to the very different physics of light and electricity. Newton imagined a ray of light to be an emission of particles in a straight line from the bright body. The phenomenon of refraction led to the conclusion that a refracting substance, such as water or glass, exerted an attraction on the particles of light. From this it should follow that the velocity of light in water or glass was greater than that in air or vacuum. But later experiments proved the contrary, and the Wave Theory of Huyghens gained acceptance. Light was conceived as an undulation, transmitted with great though measurable velocity through an elastic medium, the aether, pervading all space unoccupied by matter as we know it. we know it. The fact that two rays of light, when brought together, even though travelling in the same direction, do not necessarily produce