[Dr. Sivana]

Now you made me have to bring out the big guns.

My print edition of The Oxford English Dictionary has Scotch as the dominant usage except for formal speech. Used by real Scotch poets like Burns, etc. (See lines marked with red in margin).

http://sittnick.net/scotch_1.jpg

zoomed version

If you want an American dictionary, my 1968 World Webster's Unabridged (fake Webster's) is still serviceable:

http://sittnick.net/scotch_3a.jpg

[TokarevM57]

....well, stone the crows....!!! I guess we are both right, depending on how we wish to use the words Scotch and Scottish....although admittedly I never heard the term “Scottish whisky”..... may the wind always be at your back, laddie.....have a nice day......