Private Masses may be of the Ember Saturday: the Ember Saturday Mass has an ancient structure consisting of a series of liturgical units comprising of collect, OT reading and gradual. Before the collects, after Oremus, the deacon chants Flectamus genua and the sub-deacon Levate. Traditionally, ordinations to the various grades took place between these units. The last unit has the end of the story of the three men in the fiery furnace of King Nabuchodonosor (c.f. twelfth prophecy on Holy Saturday) and for its ‘gradual’ the hymn Benedictus es Domine Deus patrum nostrorum. This is followed by the collect of the three men, Deus qui tribus, then the second collect of the feast of SS Eustace and his Companions, the third collect of the Vigil of St. Matthew. The Mass continues then as usual but with Benedicamus Domino in place of Ite, missa est and the last Gospel of the Vigil. The deacon and sub-deacon wear violet folded chasubles. Four candlesticks are on the altar.
A private Mass may also be of the Vigil with second collect of the feast of St Eustace, the third collect of the Ember Saturday, Omnipotens sempiterne Deus. Again as in the Ember Saturday Mass Benedicamus Domino is sung but the last Gospel is of the Ember Saturday. In this case the deacon and sub-deacon wear violet dalmatic and tunicle. As for the Ember Saturday Mass four candlesticks are on the altar.
Vespers are first vespers of St. Matthew the Apostle and Evangelist with a commemoration of the preceding office of SS Eustace and of the fourth Sunday of September and XIX after Pentecost (the antiphon at the Magnificat being Adonai, Domine). When vespers are celebrated solemnly there will be four pluvialistæ in pariti assisting the Hebdomadarius in red vestments.
Followers of the 1962 liturgical books will celebrate a completely different liturgy today. The feast of SS Eustace and his Companions has been stripped down to a mere commemoration in the Saturday Office of the BVM. The Vigil of St. Matthew has been abolished. Mattins has but one nocturn with completely different scriptural lessons. When, in a week’s time, the 1962-ists celebrate Ember Saturday a novel mini-version is permitted: after the first prayer, OT lesson and gradual all the other units are missed out and the former second prayer is sung in place of Deus, qui tribus (without Flectamus genua etc) and any commemorations then made (a relative rarity by 1962). Folded chasubles have gone as has Benedicamus Domino.
In 1962 vespers St. Matthew does not even get a mention and ‘green’ vespers of the third Sunday of September are sung (with the antiphon at the Magnificat Ne reminiscaris that was sung last Saturday in the traditional rite). St. Matthew only gets a commemoration at Lauds and read Mass. Again a good illustration of John Eppstein’s point. (vide:http://ordorecitandi.blogspot.com/2008/08/st-bartholomew-apostle.html)