The size of each character (This scales the whole text).

	GetComponent(TextMesh).characterSize = 10;

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void Example() {
        GetComponent<TextMesh>().characterSize = 10;
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def Example() as void:
		GetComponent[of TextMesh]().characterSize = 10