THERE'S a book to be written about Donald Trump and the psychology of hair.

Why else would a man buy 17 golf courses?

Just imagine him sprawled on a fairway, purring as he runs his fingers through the thick turf.

"Isn't it lush? Isn't it natural? Don't you love the way it stays put in the wind?"

While upstairs his own ­desiccated tussock keels over drunkenly at the faintest zephyr.

Over-compensating again for his hypnotically bad barnet, the US billionaire yesterday announced plans to invest "at least £100m" in course 17.

Or Trump Turnberry, as it has been known since the 68-year-old tycoon paid £36m for the Ayrshire links and five-star hotel in April.

Holding court in the resort's main restaurant, he announced the Ailsa course, host to four Open championships, including 1977's "Duel in the Sun" between Tom Watson and Jack Nicklaus, would benefit from improvements to the 10th and 11th holes.

The "decent" second course will be made "magnificent", he said, and the famous lighthouse looking to Ailsa Craig will be a new halfway house.

But although Turnberry's place on the Open rota was a factor in the purchase, Mr Trump didn't yet know if it would host the Championship in 2019, the last vacant slot for years to come.

It was a tamer Donald than Scotland is used to.

His livid spat with Alex Salmond over a wind farm near his other Scottish course, at Menie near Aberdeen, was dismissed as a "little argument" and he said he now had respect for the First Minister.

He said: "I actually like Alex Salmond, but I have to fight him. I created a masterpiece [at Menie] and I don't want to see it hurt by a very, very foolish technology that's obsolete."

Turnberry would also be a masterpiece, he said.

"I'm an artist. I really am an artist at things like this. I will make this resort the finest of its kind in the world."

As for putting his name on the place, "I'm not doing it for ego, I'm doing it because it's going to make the place more successful."

It was also a more family-friendly Donald, as he introduced his son, Eric, and wife Melania. "Eric is a good student, wouldn't you say that's true, Melania? ­Melania, my wife is here."

A quick glance along the front row confirmed an outcrop of diamond and legs belonging to the former Slovenian model 24 years his junior.

His son repaid the schmaltz with interest.

Promising to redo every suite and make "every corner moulding, every chandelier" the best in the world, he looked at dad and said: "We're going to have a blast doing this. To see the joy and happiness in his eyes, I look at him and ... Turnberry is something he truly deserves."

"Thank you, son," croaked the old man.

Mr Trump, whose mother was a Stornoway MacLeod, did not have a view on Scottish independence, but said it would not affect his investment.

"I hear bad things about it from people that are very smart. I hear things would not be good for Scotland ... taxes will go up. Where is all that subsidy going to come from if you don't have the source?

"So a lot of people ... think it's a negative for Scotland, but I don't have a view. The problem with the other is you don't know what's going to happen.

"It's nice to be rich. If it turns out bad, it's bad, you know. It would be too bad."

After an hour of relentless self-promotion, the photographers finally got their hair shot.

As he posed outside, a stiff breeze worked its magic and the hitherto limp bouffant stirred like a waking polecat, the fringe rising higher and higher until it was framed majestically against the shimmering Firth of Clyde.

He clearly knew the score, but didn't care. It was all publicity and money. If that book ever does get ­written, he'll be the first to sign it-- for a percentage.