You probably have never heard about this Johann Galletti. But probably you know the type of the absent-minded professor. Galletti was such a man, and for a long time he was the most known absent-minded professor in Germany.  And so it happened:

Life of Galletti very briefly

Johann Galletti's father, Giovanni Andrea Galletti, was an opera singer of Italian origin. He was in service of the Duke of Sachsen-Gotha [1]. Galletti, the singer, was married to a German actress, and on occasion of a guest performance in Sachsen-Altenburg this Elisabeth Galletti gave birth to Johann Georg August Galletti in 1750. Even though our future absent-minded professor was born in Altenburg, nearly whole the time of his life Galletti spent in Gotha (except of some studying and trainee years in Goettingen and Schlotheim). Galletti went into teaching on Gotha Gymnasium in 1778 and stayed there till 1819. 

He was an acknowledged historian, besides he teached Geography, Latin and Natural-history. Although he was married twice, his real love was reading & writing, and reading & writing again. He published a World-history in 27 fat volumes, a German history (10 volumes), a Thuringian history (6 volumes), a history of the Sachsen-Gotha dukedom (5 volumes) and an uncounted number of other books and essays about history and geography. Between reading and writing about all the countries, regencies and wars, surrounded by bookworms, he became an odd bookworm himself, and the real live became hard to an increasing degree. When Galletti's thoughts made somersaults or went cross-country, he said some more and more funny peculiar things. His students did collect Galletti's stylistic howlers and tongue slips, and 1878, 50 years after his death, they were published first (and from then time after time). This "Galletiana" are the lighthouse of a small German literary genre named Kathederblüten (unfortunate turns of phrases, especially by teachers).

Some tasts of Galletti sayings

This probably is a premiere. As far as we know Galletti's howlers have never before been published in English. Particular thanks go to certain newsgroup participants [2] for their help in finding proper English wording; especially to Stephen Hust, Andrew Bossom [3], Arfur Million and Ray.

As for the birds of Saxony, the largest of these is the jackass. [4]

After the Battle of Leipzig you could see horses with three, four, or even more legs shot off running loose all over the countryside.

The islands of the Mediterranean are all larger or smaller than Sicily.

When Humboldt climbed Mount Chimborazo, the air became so thin that he could no longer read without glasses.

The African Lion usually grows up to the age of ten, and from then on, its size simply increases.

The angora rabbit is one of the strangest but most useful of insects.

Indeed, Councillor, I am well pleased with Blädner, but with Seifert not at all; but at least he's better than Blädner.

Don't contradict what I never told you.

Gotha is not much farther from Erfurt than Erfurt from Gotha.

If we assume that a cannonball travels a quarter of an hour in just a few seconds, then it will just about reach Erfurt.

So you think that history is as easy as playing Snap? Ha! You can learn history in a flash, but learning Snap takes years of hard graft. [5]

Reading in bed at night is a foolish habit; We have several examples of people who forgot to put out their candles at night, and when they woke up the next morning, had been burned to death.

Footnotes
[1] By the way: British Empire's Prince Albert and Queen Victoria (on her distaff side) are related to this lineage
[2] de.etc.sprache.misc and alt.usage.english
[3] named rewboss (don't miss his website!), 
[4] Bird in German (Vogel) can mean a vertebrate as well as a odd person.
[5] Snap stands for an easy-to-learn card game. Galletti spoke about Schnarps, also named Sixty-six, a German version of Mariage. 200 years ago in Gotha it was a student's favorite way of passing the time between (and perhaps during) the lessons.

Picture:  
Old drawing by Wilhelm Busch (from the Comic "Ker and Plunk")