"A" or "An," before Words, beginning with a Vowel

Your readers are much indebted to Dr. Kennedy for his late exposure of the erroneous, though common, use of the phrase "mutual friend," and I am convinced that there are many similar solecisms which only require to be denounced to ensure their disuse. I am anxious to ask the opinion of Dr. K., and others of your subscribers, on another point in the English language, namely, the principles which should guide our use of "A" or "An" before a word beginning with a vowel, as the practice does not appear to be uniform in this respect. The minister of my parish invariably says in his sermon, "Such an…