I can speak to the political nature.

In February of 1858 Victoria revealed her choice, Bytown, on the Ottawa river. On July 28th of that year, an opposition member from Canada East proposed a motion (presumably of confidence) that declared the location unsuitable. A number of individuals in Macdonalds caucus actually supported the motion and government was defeated on July 29th. Macdonald resigned as Premier.

The Governor General invited the opposition to form government. At that time, incoming ministers needed to resign their seats in Parliament and go back to their constituents to hold a by-election to determine whether they still held the support of their constituents. If a minister held office within 30 days prior they did not need to go to a by-election.

At this time, Macdonald, leading the Conservatives and many ex Reformers held a majority in the legislature, and so took down the Liberal government led by Brown on August 4th. The Governor General refused Browns request to dissolve Parliament after his defeat, and Macdonald and his allies were able to take control of the legislature for the second time in a month on August 7th. Since it was under 30 days, no by-elections were necessary.

Now I might get nailed on the formatting, but source is Conrad Blacks Rise to Greatness, The History of Canada pg. 288-9