It was into this busy scene of mechanical industry and skill that our party of travellers were now coming. But before I resume the narrative of their adventures, I will say a word about those parts of Scotland which lie to the north and south of these central regions that are occupied by the valleys of the Forth and the Clyde. The region which extends to the southward--that is, which lies between the valleys of the Forth and the Clyde on the one hand, and the English frontier on the other--is called the southern part of the country. It consists, generally, of fertile and gently undulating land, which is employed almost entirely for tillage, and is but little visited by tourists or travellers. The northern part of Scotland is, however, of a very different character; being wild, mountainous and waste, and filled every where with the most grand and sublime scenery. The eastern portion of this part of the island is more level, and there are several large and flourishing towns on or near the shores of it, such as Inverness, Aberdeen, Dundee, Perth, and others. But the whole of the western side of it consists of one vast congeries of lakes and mountains, so wild and sombre in their character that they have become celebrated throughout the world for the gloomy grandeur of the scenery which they present to the view. These are the famous Scottish Highlands. Mr. George's plan was first to visit the valley of the Clyde, and its various mines and manufactories, and then to take a circuit round among the Highlands, on his way to Edinburgh. CHAPTER III. ARRIVAL AT GLASGOW. One of the greatest drawbacks to the pleasure of travelling in Scotland, especially among the Highlands, is the rain. It usually rains more in mountainous countries than in those that are level, for the mountains, rising into the higher and colder regions of the atmosphere, chill and condense the vapors that are floating there, on the same principle by which a tumbler or a pitcher, made cold by iced water placed within it, condenses the moisture from the air, upon the outside of it, on a summer's day. It is also probable that the mountain summits produce certain effects in respect to the electrical condition of the atmosphere, on which it is well known that the formation of clouds and the falling of rain greatly depend--though this subject is yet very little understood. At all events, the western part of Scotland is one of the most rainy regions in the world, and travellers who visit it must expect to have their plans and arrangements very often and very seriously interfered with by the state of the weather.