The most obvious difference is that in 1940, the feast was called Whitsunday. As the 1912 New Catholic Encyclopedia writes:
Pentecost (Whitsunday)The two have a surprisingly similar approach. Hymnal 1940 lists 5 Whitsunday hymns (#107-111) and Hymnal 1982 lists 8 Pentecost hymns (#223-230). This morning, we opened with the most memorable hymn on either list: Salve Festa Dies (H40: #107, H82: #225), i.e. the Pentecost variant of Ralph Vaughan Williams’ second greatest hit (after his Nov. 1 classic).
A feast of the universal Church which commemorates the Descent of the Holy Ghost upon the Apostles, fifty days after the Resurrection of Christ, on the ancient Jewish festival called the "feast of weeks" or Pentecost (Exodus 34:22; Deuteronomy 16:10). Whitsunday is so called from the white garments which were worn by those who were baptised during the vigil; Pentecost ("Pfingsten" in German), is the Greek for "the fiftieth" (day after Easter).
Whitsunday, as a Christian feast, dates back to the first century, although there is no evidence that it was observed, as there is in the case of Easter; …
That Whitsunday belongs to the Apostolic times is stated in the seventh of the (interpolated) fragments attributed to St. Irenæus. In Tertullian (On Baptism 19) the festival appears as already well established. The Gallic pilgrim gives a detailed account of the solemn manner in which it was observed at Jerusalem ("Peregrin. Silviæ", ed. Geyer, iv). The Apostolic Constitutions (Book V, Part 20) say that Pentecost lasts one week, but in the West it was not kept with an octave until at quite a late date. It appears from Berno of Reichenau (d. 1048) that it was a debatable point in his time whether Whitsunday ought to have an octave. At present it is of equal rank with Easter Sunday.
What’s interesting in both hymnals is that the real hymnody comes from the list of hymns about the Holy Spirit (née Holy Ghost). For H40, it’s under “also the following” (13 hymns total) while H82 it’s under a section formally titled “Holy Spirit” (#500-516). Many of the great hymns fall under this category, include “Come, Holy Spirit, Heavenly Dove” (H40: #369; H82: #510) that we sang today.
One we didn’t sing was “Come down, O Love divine” (H40: #376, H82: #516), but with the 15th century lyric and the wonderful Vaughan Williams tune Down Ampney, we really should have. (After I wrote this posting, I noticed that bjs of Chantblog posted today a tribute to this, “the best hymn ever written.” High praise indeed.)
The other hymn I wish we had sung (perhaps at communion) is “Come, Holy Ghost, our souls inspire” (H40: #217, H82: #504) to Veni Creator. However, I understand the decision not to use it, because this Sarum (i.e. medieval Salisbury) chant requires either a good quality choir or an moderately large and experience congregation. I love plainsong but have come to recognize through my wanderings among the Anglican diaspora is that the average parish can’t handle plainsong without considerable practice.
Neither hymnal considers “Take my life, and let it be” (H40: #408; H82: #707) to be a hymn about Pentecost or the Holy Ghost. I disagree, but maybe that’s just how a particular Pentecost sermon struck me two years ago.
Overall, I think that H82 made a good choice to group some (even if not all) of the Holy Ghost hymns into one place — making it easier to find a good Pentecost hymn under “H” if not under “P”.