Hilloa

1890, William Morris, News from Nowhere Chapter XXII http://en.wikisource.org/wiki/News_from_Nowhere/Chapter_XXIIAs for Dick, he looked at her admiringly a while, and then said at last: "Well, Clara, I do wish we were there! But, hilloa! we are getting back way."
1883, Howard Pyle, The Merry Adventures of Robin Hood, Chapter XIIIhttp://en.wikisource.org/wiki/The_Merry_Adventures_of_Robin_Hood/Chapter_XIII"Hilloa, brother," quoth Tuck, "let me aid thee." So saying, he took the key from the other's hand and quickly opened the door with a turn of it.
1847, James Malcolm Rymer and Thomas Peckett Prest, The String of Pearls Chapter 32http://en.wikisource.org/wiki/The_String_of_Pearls/Chapter_32'Ah,' muttered Todd to himself, 'I like boys of a religious turn. They are much easier managed, for the imagination in such cases has been cultivated at the expense of the understanding. Hilloa, who have we here?'

Full definition of hilloa

1836, James White, The adventures of Sir Frizzle Pumpkin, Nights at mess, and other talesI heard old Jenkins, scarcely recovered from the effects of his potations, hilloaing at the top of his voice for Julia