Basically, in 1850 and 1890, the question was still very much which 100 or 1000 miles. Communication infrastructure was static and capital-intensive. As a result, communicating along much-used avenues was often quick and convenient while getting in touch with out-of-the-way places could be incredibly demanding in terms of resources and time.
Communicating over the 100 miles between, say, London and Birmingham or Paris and Le Havre even in 1850 would, bar the absence of the telephone, have looked very similar to the way it did until the 1990s - you posted a letter and it would be delivered the next morning. If things were very urgent, you could send a telegram which took only hours. Of course, once we're talking about a different kind of 100 miles - say between Gdansk and Warsaw, or Yaroslav and Vologda - you'de be looking at several days' transit time and not necessarily daily postal services or telegraph, and the connection between Boma and Maquela might give you half a year's turnaround time if you paid for a messenger and his armed escort.
By 1890, the infrastructure had expanded to the point that almost any urban centre was reachable within a few days at most from its 100-mile periphery, and most postal services would deliver overnight over such distances. THere were, of course, many areas where communication was still as fast as a messenger could walk, but the greater part of the Western world had become postalised them.
Communication over 1000 miles in 1850 meant that you either had some kind of sea route, or were looking at very lengthy travel times. You could already post international letters, but it was complicated and expensive and the journey from, say, London to Rome or Paris to St Petersburg took weeks. And that was in the middle of civilised Europe. Telegraphs over that distance were just being pioneered and as yet, there was no regular service. Sending a message from, say, Port Banana to (the future site of) Stanleyville might well require several years' hard work to assemble an expedition, stockpile the trade goods, hire guides and negotiate passage.
By 1890, international and deep-sea telegraphs were established technology and fast mail steamers plied all major routes, with travel times between Europe and America cut to under ten days. You could send a message from London to Simlah or San Francisco and have an answer the same day (again, the infrastructure only gopes so far - a telegram from London to a tiny village in Darjeeling would take a few hours to within 100 or so miles of its destination and then several days by post runner). I have a lovely little detail-obsessed pocket atlas printed in 1890 that claims that within five days, you (and your mail) could reach Moscow, Constantinople, Naples, Gibraltar, Stockholm or Bergen from London.- Within ten days, Boston, New York, Philadelphia, Aden, Arkhangelsk and Sierra Leone, within twenty San Francisco, Rio de Janeiro, Capetown, Delhi, Madras, Tobolsk and Vancouver. Within fourty days, a letter could be in anwhere but the polar region, northern Siberia, Central Africa, Central Asia, inner Australia and non-coastal South America. Even the upper Amazon is marked as '30 to 40 days'. So you're looking at remarkably good communication from a purely technical point of view. Of course it was still quite costly and not something people did frivolously.
If you are interested, you might want to read 'The Victorian Internet'. A fascinating history of the telegraph.