in Mechanics, the matter of any body cohering with it, i.e. moving and gravitating along with it. In which sense, mass is distinguished from bulk, or volume, which is the expansion of a body in length, breadth, and thickness.

The mass of any body is rightly estimated by its weight; and the masses of two bodies of the same weight are in a reciprocal ratio of their bulks.

Mass, Missa, in the church of Rome, the office or prayers used at the celebration of the eucharist; or in other words consecrating the bread and wine into the body and blood of Christ, and offering them for transubstantiated as an expiatory sacrifice for the quick and the dead.

As the mass is in general believed to be a representation of the passion of our blessed Saviour, so every action of the priest, and every particular part of the service, is supposed to allude to the particular circumstances of his passion and death.

Nicod, after Baronius, observes that the word comes from the Hebrew milach (oblation); or from the Latin missa missorum; because in the former times, the catechumens and excommunicated were sent out of the church, when the deacons said Ite, missa est, after sermon and reading of the epistle and gospel; pel; they not being allowed to assist at the consecration. Menage derives the word from miffo, "diffusing." Others from miffa, "miffing, tending;" because in the mass, the prayers of men on earth are sent up to heaven.

The general division of masses consists in high and low. The first is that sung by the choristers, and celebrated with the assistance of a deacon and sub-deacon; low masses are those in which the prayers are barely rehearsed without singing.

There are many different or occasional masses in the Romish church, some of which have nothing peculiar but the name: such are the masses of the saints; that of St Mary of the snow, celebrated on the fifth of August; that of St Margaret, patroness of lying-in-women; that of the feast of St John the Baptist, at which are said three masses; that of the innocents, at which the gloria in excelsis and the hallelujah are omitted, and it being a day of mourning, the altar is of a violet colour. As to ordinary masses, some are said for the dead, and, as is supposed, contribute to fetch the soul out of purgatory: at these masses the altar is put in mourning, and the only decorations are a cross in the middle of fix yellow wax-lights; the dress of the celebrant, and the very mass-book, are black; many parts of the office are omitted, and the people are dismissed without the benediction. If the mass be said for a person distinguished by his rank or virtues, it is followed with a funeral oration; they erect a chapelle ardente, that is, a representation of the deceased with branches and tapers of yellow wax, either in the middle of the church, or near the deceased's tomb, where the priest pronounces a solemn abolition of the deceased. There are likewise private masses said for stolen or strayed goods or cattle, for health, for travellers, &c. which go under the name of votive masses. There is still a further distinction of masses denominated from the countries in which they were used; thus the Gothic mass, or missa mozarabum, is that used among the Goths when they were masters of Spain, and which is still kept up at Toledo and Salamanca; the Ambrosian mass is that composed by St Ambrose, and used only at Milan, of which city he was bishop; the Gallic mass, used by the ancient Gauls; and the Roman mass, used by almost all the churches in the Romish communion.

Mass of the Prefanctificati (missa praefanctificatorum), is a mass peculiar to the Greek church, in which there is no consecration of the elements; but after singing some hymns, they receive the bread and wine which was before consecrated. This mass is performed all Lent, except on Saturdays, Sundays, and the annunciation. The priest counts upon his fingers the days of the ensuing week on which it is to be celebrated, and cuts off as many pieces of bread at the altar as he is to say masses; and after having consecrated them, sleeps them in wine, and then puts them in a box; out of which, upon every occasion, he takes some of it with a spoon, and putting it on a dish sets it upon the altar.