The Somme is a fairly bloody battle and if we do the math of it it would look like this.

In the first day of the Battle of the Somme there where 57,470 British casualties, 7,000 French and 8,000 German so that puts the first day of the Somme at 3019~ casualties per hour[.

The full battle of the Somme was about 123 days in length with a total ranging from 860,000~ loses on both sides to 1,124,000~ loses (German numbers aren't exact).

So that puts loses at anywhere between 291-381 per hour.