Question about Prague Symphony by Mozart

[steven1990]

Lately I've been studying Mozart's 38th Symphony (great work!). But looking at the instrumentation I have a few questions.

Mozart writes 'Corno I,II in D', 'Clarino I,II in D' and 'Timpani in D-A'. First, am I correct when I say that Corno means French Horn and Clarino means Clarinet? I don't understand why he writes both of them in D? In my lessons about instrumentation I was taught that the Clarinet is in Bes and the French Horn in F, meaning that you have to transpose the Clarinet-part a major second higher and the Horn-part a perfect fifth higher. But Mozart transposes both the instruments a major second lower? Can someone please explain this to me?

Further; I always thought that the timpani didn't have to be transposed. But in this score the timpani are transposed a major second lower. This means that there is a C written, but there sounds a D.

I hope that you can understand me and explain it to me. Thanks in advance!

[neardn]

corno is italian for horn, so yes un corno is a french horn

a clarino i believe is actually a trumpet

through the 17th and 18th century timpani were transposed
usually to the tonic or dominant note

which would make sense that it would be tuned to D A for this symphony