[60] The only trade which Glasgow carried on with foreign countries previous to the Union, was in coal, grindstones, and fish,--Glasgow-cured herrings being in much repute abroad. After the Union partnerships were formed; vessels were built down the Clyde, and chartered for carrying on the trade with Virginia, Maryland, and Carolina. The first _honest_ vessel crossed the Atlantic from the Clyde in 1719; in 1735 the Virginia merchants in Glasgow had fifteen vessels engaged in the trade, and the town shortly after became the great mart for tobacco. Of the 90,000 hogsheads imported into the United Kingdom in 1772, Glasgow alone imported 49,000, or more than one-half. The American Revolution had the effect of completely ruining the tobacco trade of Glasgow, after which the merchants were compelled to turn to other fields of enterprise and industry. The capital which they had accumulated from tobacco enabled them to enter upon their new undertakings with spirit, and the steam-engine which had by that time been invented by their townsman James Watt, proved their best helper in advancing the prosperity of modern Glasgow. The rapidity of its progress may be inferred from the following facts. In 1735, though the Glasgow merchants owned half the entire tonnage of Scotland, it amounted to only 5600 tons. In that year the whole shipping of Scotland was only one-fortieth part of that of England: it is now about one-fifth. From 1752 to 1770 the total tonnage dues of the harbour of Glasgow amounted to only 147_l._, or equal to an average of about 8_l._ per annum. In 1780, the Clyde having been deepened in the interval, they reached 1515_l._; and in 1854, they amounted to 86,580_l._ The increase has been quite as great in later years. In point of value of exports, Glasgow ranks fourth among the ports of the United Kingdom; and Greenock now takes precedence of Bristol. [61] For many curious particulars of Old Glasgow and its society, see Dr. Strang’s ‘Glasgow and its Clubs.’ [62] a temporary wooden theatre was run up in 1752, but the religious prejudices of the population were violently excited by the circumstance, and the place was attacked by a mob and seriously damaged. The few persons who went there had to be protected from insults. In 1762, when some persons proposed to build a theatre, not a single individual who had ground within the burgh would grant them a site. Two years later the theatre was erected outside the precincts, and on the night on which it was opened it was wilfully set on fire by some persons instigated by the preaching of a neighbouring methodist, when it narrowly escaped destruction.