Question about Prague Symphony by Mozart

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!

I believe clarino is a trumpet.

therefore, trumpets in D.

horns in D were natural horns, with crooks to place them "in D".

the modern horn in F (technically, a double horn in F and Bb) has valves and has no need for crooks, since it can play chromatically. however, it did not exist at the time of mozart.

as for the timpani, it was usual at that time to simply write the tonic and dominant as notes for timpani, since those were the most common notes it played. Again, the timpani at that time was not capable of being retuned during the piece. The timpanist tuned his pair of drums before the piece, and they remained tuned throughout the piece.

Okay, thanks a lot for your answer! I understand that it was impossible to retune the timpani during the piece, but I wonder why the timpani are transposed in this score: DME::NMA_KB_SYNOPSIS

In other scores there is just a D written in the first measures, while in this score there is a C written (that sounds like a D I guess)

Like the trumpets/horns, the timpani were sometimes scored "in C", so the 'C' was the tonic, and the 'G' was the dominant, regardless of whatever key the piece is actually in.

Oooh, okay, now I get it. Thanks a lot!:D