Between 1840 and 1843, Norman MacLeod, minister of St. Columba's, which served the many Gaels who migrated to Glasgow, published a magazine, Cuairtear nan Gleann. The sole purpose of the periodical was to provide information about emigration to a Gaelic-speaking audience. Sheila Kidd of the University of Glasgow analyzed MacLeod's publication in a 2002 article, "Caraid nan Gaidheal and 'Friend of Emigration': Gaelic Emigration Literature of the 1840s."
By the mid-19th century an increasing number of Gaels were becoming literate in Gaelic and English, so Gaelic publishing was a growth industry (in a manner of speaking). More importantly, emigration was a central topic in Scotland's national discourse; not unlike the current debate about immigration in the United States.
The Highlands had just emerged from a period of famine in the late 1830s and more and more landlords began to see emigration as the solution to their problems and those of their tenants. Kidd explains that MacLeod was often more a friend of emigration than a friend of the Gaels; meaning he probably thought it was a good idea for Gaels to leave Scotland rather than for them to oppose their landlords and eviction. Many of the articles that appeared in Cuairtear nan Gleann fall into three categories. First, that Highlanders should accept the situation passively. Second, emigration is framed in a spiritual context: the emigrant's journey is nothing compared to the final journey we must all face. Third, many articles promoted specific emigrant destinations and suggested that Highland communities in Australia, New Zealand or America really weren't that different from those in Scotland.
While MacLeod hoped to provide an honest forum of information for potential emigrants, most Highlanders who were determined to emigrate were probably influenced more by correspondence from friends and family members who had already emigrated than they were by a minister in Glasgow.
If you are a family historian, the article will provide insight to your ancestor's world because whether they stayed in Scotland or left, they were impacted by emigration. If you are a student writing a paper on Scottish emigration, this would be a good source on information available to potential emigrants and the general tenor of emigration rhetoric in Scotland during the 19th century. And, I speak from experience, instructors are always impressed when you use an academic article as a reference.
Dr. Kidd's article appeared in the April 2002 edition of the Scottish Historical Review and is available through JSTOR or Academic Search Premier. You should be able to access it through a University Library or large public library.
10/20/11: ADDITION- You can also access Dr. Kidd's article here via Enlighten, a database of research publications by University of Glasgow Staff. Thanks for the tip Peter!