"We use smoke flares," Paolo Sagretti, who was in charge of setting up the chapel for the election conclave, told AFP.

The ancient signalling system - still the only way the public learns whether a pope has been elected - used to involve mixing wet straw with the ballots to produce white smoke, and pitch to create black smoke.

After several episodes in which greyish smoke that could be interpreted as white or black created confusion, the Vatican introduced the surer system starting with the last conclave in 2005.

The Vatican now uses a mixture of potassium perchlorate, anthracene and sulphur to produce black smoke and potassium chlorate, lactose and rosin for white, the Vatican says on its website.

Two stoves stand in a corner of the chapel, one for burning the ballots and the other for the chemicals, with the smoke from both stoves going up a common flue.

An electronic control panel allows the choice between the two, and the correct compound is burned at the same time as the used ballots.

Sources

• NDTV

The last time cardinals in a conclave did not choose one of their members was in 1378 when they voted for the archbishop of Bari, Italy, who became Pope Urban VI.

The following is what should happen as soon as a candidate receives at least two-thirds — 77 — of the votes and is elected the 266th successor of St. Peter.

If he is not the one elected, Cardinal Giovanni Battista Re, the top-ranking cardinal elector, will ask the chosen cardinal, "Do you accept your canonical election as supreme pontiff?"

The ritual handbook for the conclave and election gives no formula for the candidate's response and gives no instruction for what would happen if the person declined.

Instead, it says, "as soon as he receives the consent," the top-ranking cardinal elector asks, "With what name do you want to be called?"

The master of papal liturgical ceremonies, Msgr. Guido Marini, a notary and two aides serving as witnesses draw up an official statement of the election and the name.

If the chosen candidate is not in the room, the top-ranking cardinal calls a top official in the Vatican Secretariat of State, Archbishop Giovanni Becciu, who "with great caution" and without letting the news leak, must get the new pope to the Vatican.

If the candidate chosen is not yet a bishop, he is immediately ordained.

Only after the candidate accepts his election and is ordained, if necessary, the ballots are burned with chemicals to produce white smoke and announce to the world a successful election, said Jesuit Father Federico Lombardi, Vatican spokesman.

The bells of St. Peter's Basilica will begin to peal, television and radio stations will broadcast the news, Twitter feeds and other social networks will pass the word, and tens of thousands of people in Rome will run to St. Peter's Square.

The new pope goes into the so-called "Room of Tears," a small room attached to the Sistine Chapel, and dresses in a white cassock and other papal vestments.

Then there is a brief prayer ceremony in the Sistine Chapel with the cardinal electors. The ceremony includes the reading of the words of Jesus to Peter either from the Gospel of Matthew — "You are Peter and upon this rock I will build my church" — or from the Gospel of John, "Feed my sheep."

Each of the cardinals present in the Sistine Chapel comes up to the new pope, paying him homage and promising him obedience, then they sing together the "Te Deum" hymn of thanksgiving to God.

If he is not the one chosen, Cardinal Jean-Louis Tauran, the top-ranking cardinal deacon, will go to the balcony of St. Peter's Basilica and announce the election to the crowds in St. Peter's Square.

But before stepping out onto the balcony, Father Lombardi said, the new pope will stop in the Pauline Chapel of the Apostolic Palace to pray briefly before the Blessed Sacrament.

Cardinal Tauran, or the top-ranking cardinal deacon after him, goes out onto the balcony and tells the crowd, "I announce to you a great joy. We have a pope ('Habemus papam')," saying the name of the one chosen and announcing the name by which he will be called.

The new pope then comes out onto the balcony and gives his first blessing "urbi et orbi" (to the city and the world) and usually gives a short speech.

For the crowds in St. Peter's Square and for those watching on television or listening on the radio, devoutly following the new pope's blessing carries a plenary indulgence, Father Lombardi said. He did not say if the indulgence applies to Twitter followers.

Sources

• CNS
• Image: BBC

Allen's models are:

• Let's get it over with
• The anti-establishment vote, or
• The 'third world' hypothesis

Let's get it over with

This model brings together those wanting to have the new pope installed by Holy Week, and not wanting to project an image of disunity.

For this person to be elected, Cardinals could simply note who seems to have the strongest support on the early ballots and then jump on the bandwagon.

This hypothesis assumes that most cardinals would be reasonably satisfied with any of the early leaders including Cardinals Scola, Ouellet, Scherer and Sandri.

The anti-establishment vote

This scenario gathers those cardinals who want to challenge the old guard in the Vatican and installing a new way of doing business.

The Roman Curia theoretically has 38 cardinals but it is unlikely they will act as a group.

The anti-establishment vote could unite moderates in the College of Cardinals and cardinals from the developing world who wonder if the powers that be in Rome understand their local situation.

But Allen says it's difficult to identify a candidate who is in a position to deliver real reform, however should such a figure emerges, there's a fairly clear path to 77 votes for that man.

The Third World hypothesis

This model presumes there's a solid pocket of voters in the College of Cardinals who would like to elect a pope from outside the West.

However while this sentiment exists, there does not appear to be a single clear canditate.

Allen suggest that if there were, he might have the position largely sown up.

However, Allen writes, should a consensus candidate from Latin America emerge before Tuesday afternoon, one can presume he'd draw most of the votes from his own cardinals (19), Africa (11), and Asia (10), which already brings him to 40, which he could get from some European moderates and the anti-establishment group.

Source

• Corriere Della Sera