From Riehn
Possible Battle of Vitebsk (July 26 or 27)

On the 27th the French had (in march order)
                                                men        figs
1. I and II Cav Corps (- Div Valence)          13,000      162
2. IV Corps w/ Bav Cav                         37,000      308
3. I Corps (3 div)  Mouton-Lobau               32,000      267
   (- Desaix, Compans and cav)
4. Guard (- Vistula Legion, Colberts brig)     28,000      233
5. III Corps (-2 regt)                         25,000      208

                                   total      135,000
(This total seems high compared to the initial numbers given in
Nafzinger.)

On the 25th, Barclay had approx 75,000 men.
III, IV, V, VI inf Corps,  I, III Cav Corps