After doing a little work on this, I'm quite certain holy smoke is not a minced oath nor an obscuration or euphemism for any more blasphemous exclamation. Its use as an exclamation also predates the Kipling quote by at least a decade. I found this
example from a poem by Cormac O'Leary in an 1882 edition of The Reading Club, a collection of prose and poetry (date check on p. 102):
I found several other references from the 1880s as well. @Master's comment is correct—and significant. Several of the early examples of its use read by the holy smoke. This is one reason I don't believe the exclamation is a euphemism for anything else. It was simply a shortening of this oath. And of the origin of this oath? I think @Chris Dwyer's answer nailed it. Google Books' listings of the phrase from the same time period are replete with religious references to "holy smoke." A closer look at most of them reveals that their context is in fact one of sacrifice or burnt offering as in this 1863 exegesis of a passage from Isaiah:
Michael Quinion's discussion of the phrase at World Wide Words points out the same sacrificial origin. For lack of a clear connection, however, he concludes that holy smoke was likely "invented anew as a mock-religious exclamation and mild oath on the model of the older holy Moses." I disagree. I think the oath by the holy smoke is a clear connection between the holy smoke of burnt offerings in Christian writings and the later shortened exclamation we still hear today.
"Holy crap on a cracker! That paint job would cost three or four
thousand dollars in the city,” exclaimed John loudly. When John saw
the expression on James's face, he knew he had said too much. “But, of
course, they rip people off in the city, and you're not like that, are
you Gator?" said John.
In Google Groups there's an older result from Jul 13, 2001 in by John in rec.music.phish:
Holy crap on a cracker!! I wish I could go!
There's a dozen "crap on a cracker" results, the oldest is apparently from 1992's Usher's Passing by Robert R. McCammon but there's no preview to confirm. The next is 1996's The Basement by Bari Wood:
"I'd say it was crap on a cracker, Reed. But what did happen to those bees?"
The oldest "Holy * on a cracker" from Google Groups is "Holy hell on a cracker!" from Oct 12 2000 in alt.roundtable.
The related "Jesus Christ on a cracker" can be found in 1993's Save me, Joe Louis by
Madison Smartt Bell:
"Jesus Christ on a cracker," Macrae said. "You about killed me there."
also cross country, crosscountry; 1767, of roads, from cross (v.) + country, or aphetic for across-country. Of flights, from 1909.
i.e. It does not refer to movement across borders of countries, but rather across a single country (at some scale).
So, "cross-country skiing" can basically be interpreted as "skiing across [significant] terrain". Specifically, it does of course involve a very specific technique, different to that of downhill skiing. Analogies can be made with "cross-country running" as well.
Best Answer
After doing a little work on this, I'm quite certain holy smoke is not a minced oath nor an obscuration or euphemism for any more blasphemous exclamation. Its use as an exclamation also predates the Kipling quote by at least a decade. I found this example from a poem by Cormac O'Leary in an 1882 edition of The Reading Club, a collection of prose and poetry (date check on p. 102):
I found several other references from the 1880s as well. @Master's comment is correct—and significant. Several of the early examples of its use read by the holy smoke. This is one reason I don't believe the exclamation is a euphemism for anything else. It was simply a shortening of this oath. And of the origin of this oath? I think @Chris Dwyer's answer nailed it. Google Books' listings of the phrase from the same time period are replete with religious references to "holy smoke." A closer look at most of them reveals that their context is in fact one of sacrifice or burnt offering as in this 1863 exegesis of a passage from Isaiah:
Michael Quinion's discussion of the phrase at World Wide Words points out the same sacrificial origin. For lack of a clear connection, however, he concludes that holy smoke was likely "invented anew as a mock-religious exclamation and mild oath on the model of the older holy Moses." I disagree. I think the oath by the holy smoke is a clear connection between the holy smoke of burnt offerings in Christian writings and the later shortened exclamation we still hear today.