Baron d’Holbach, a native of the Palatinate, born January 1723, died 21st January, 1789, deserves special notice, as being the man whose house was the gathering place of the knot of writers and thinkers who struck light and life into the dark and deadened brain of France. He is generally reputed to have been the author of that well-known work, the “System of Nature,” which was issued as if by Mirabaud. This work, although it was fiercely assailed at the time by the pen of Voltaire, and by the _plaidorie_ of the prosecuting Avocat-General, and has since been attacked by hundreds who had never read it, yet remains a wonderfully popular exposition of the power-gathering heresy of the century, and, as far as we are aware, has never received efficient reply. Probably next to Paine’s works, it had in England during the second quarter of this century the widest circulation of any anti-theological book, this circulation extending through the manufacturing ranks. In the eighteenth century Mirabaud could, in England, only be found in the hands of the few, but fifty years had wondrously multiplied the number of readers. Joseph Priestley was born near Leeds, 13th March, 1733, and being towards the latter part of his life driven out of England, by the persecuting spirit evinced towards him, and which had been specially excited by his republican tendencies, he died at Northumberland, Pennsylvania, on the 6th February, 1804. Originally a Church of England clergyman, his first notable inclination towards heterodoxy manifested itself in hesitation as to the doctrine of the atonement. He ultimately rejected the immortality and immateriality of the soul, argued for necessitarianism, and earned considerable unpopularity by the boldness of some of his sentiments on political as well as theological matters. Priestley was one of the rapidly multiplying instances of heresy alike in religion and politics, but he provoked the most bitter antagonism. His works were burned by the common hangman, his house, library, and scientific instruments were destroyed by an infuriate and pious mob. Despite all this, his heresy, according to his own view of it, was not of a very outrageous character, for he believed in Deity, in revealed religion, and in Christianity, rather putting the blame on misconduct of alleged Christians. He said: “The wretched forms under which Christianity has long been generally exhibited, and its degrading alliance with, or rather its subjection to, a power wholly heterogeneous to it, and which has employed it for the most unworthy purposes, has made it contemptible and odious in the eyes of all sensible men, who are now everywhere casting off the very profession and every badge of it. Enlightened Christians must themselves, in some measure, join with unbelievers in exposing whatever will not bear examination in or about religion.” His writings on scientific topics were most voluminous; his most heretical volumes are those on “Matter and Spirit.”