To endeavour to instruct the ignorant, to promote piety, and to remove unhappy prejudice, are aims laudable in every christian, but are particularly objects of pastoral zeal. The Holy Sacrifice of the Mass has ever been held, by Catholics, the principal homage of the Christian religion, and assiduous assistance thereat as one of the most useful, solid, and sanctifying exercises of devotion. It also is, and for some time has been, one of the chief butts of raillery, sarcasm, and scorn, to those who are apt to blaspleme whatsoever things they know not. The view of the Author, or rather Compiler of the following short Treatise, is to afford an easy means of familiar acquaintance with all the parts of this sacred Liturgy; to show the meaning, propriety, antiquity, and authority of its Vestments and Ceremonies, as also the orthodoxy of the Doctrines on which it is founded. or are connected with it. So that Catholics may be able to demonstrate that the Worship therein paid to Almighty God, is a reasonable service; and that they who have) unfortunately and almost unwittingly, imbibed prejudice against it, may have an opportunity of examining fairly rather than condemn rashly."