Yoma, Chapter 4, Mishnah 6. This mishnah deals with the number of ma'arachos - the piles of wood and the fires that burned on top of the altar - on each and every day, and how many ma'arachos there were on the altar on Yom Kippur.
The words of the mishnah: "Bechol yom hayu sham arba ma'arachos, vehayom chamesh - divrei Rabbi Meir" - every day there were four ma'arachos there, and today there are five; these are the words of Rabbi Meir. Four piles of wood that burned separately from one another on the altar, and on Yom Kippur a fifth ma'arachah was added to them.
The four daily ma'arachos according to Rabbi Meir:
The large ma'arachah - the main fire, upon which the daily tamid offering and the rest of the offerings were placed and burned. As for the other offerings, if they were not olos, only the eimurim were burned on it, that is, certain portions of the fats.
The second ma'arachah - from which the coals were taken for burning the incense on the golden altar each day.
A ma'arachah for maintaining the fire - which served to fulfill what is stated, "a perpetual fire shall burn," and it is the permanent fire on the altar.
A ma'arachah for the limbs of the tamid - for those limbs of the afternoon tamid of the previous day that were not completely consumed during the night; the next day they would be burned on this ma'arachah.
The fifth ma'arachah on Yom Kippur: On Yom Kippur an additional ma'arachah was added, from which the coals were taken for burning the incense in the pan in the Holy of Holies. This is the opinion of Rabbi Meir.
The view of Rabbi Yosei: "Bechol yom shalosh, vehayom arba" - every day there were three, and today four. Rabbi Yosei reduces the count by one: every day there were only three - the large ma'arachah, the ma'arachah for the incense, and the ma'arachah for maintaining the fire. In his opinion there was no special ma'arachah for the limbs of the tamid that had not been consumed from the previous day; rather, they were burned on the large ma'arachah itself, at its sides. And the fourth is the ma'arachah unique to Yom Kippur, for the coals of the incense.
The view of Rabbi Yehudah: "Bechol yom shtayim, vehayom shalosh" - every day there were two, and today three. In his opinion there were only two ma'arachos each day: the large ma'arachah and the second ma'arachah for the incense, since he did not hold that a separate ma'arachah was needed for maintaining the fire. And on Yom Kippur there were three, with the addition of that ma'arachah from which the coals were taken for the incense that was brought lifnai velifnim, into the Holy of Holies.
In summary: Three views are stated in the mishnah regarding the number of ma'arachos on the altar, and each one adds a single ma'arachah on Yom Kippur for the coals of the incense of the Holy of Holies: Rabbi Meir - four every day and five on Yom Kippur; Rabbi Yosei - three and four, since the limbs of the tamid were burned on the large ma'arachah; and Rabbi Yehudah - two and three, since maintaining the fire also did not require a separate ma'arachah.