1885.] CHEMISTRY. 457 



that as good returns may still be made from plantations of it 

 planted with moderate thickness, as accrues to much mixed timber 

 wood at present existing, wliich only yields its occasional periodical 

 crops of brushwood and figgots, and generally, at rare intervals 

 apart, a fall of modei-ate-sized oak or mixed timber. Moreover, 

 where, as is occasionally the case, attempts are made to renovate 

 park lands by planting specimen trees on eligible sites, and in 

 connection with which elms are occasionally used, I would strongly 

 advise the use of tlie Huntingdon, or even the Scotch or Wych 

 elms, in preference to the commoner kind, which in too general a 

 way seems to obtain precedence." 



Ghemistry. 



DIFFERENT YIELD OF PRODUCE FROM THE TWO 

 VARIETIES OF THE OAK. 



ACCOPtDING to a report made to the Minister of Agriculture 

 by the Agricultural Society of Rhenish Prussia, the two 

 varieties of the ordinary oak {Q. Robur, L.), viz. Q. R. scssiliflora and 

 Q. R. peduncidata, give different yields of bark and tannin. The sessile 

 oak gave 2 '5 2 kilos of bark the 100 kilos of wood, or about 4 lbs. 

 the two cwt., while the pedunculated oak gave only 1 k. 92 — or 

 about 3 lbs. In the forests which were very closely planted, the 

 bark gave only 14'78 per cent, of tannin, whilst in those freely 

 open to the influence of the sun, as much as 15'77 per cent, of 

 tannin was obtained. The mean yield of the bark from the sessile 

 variety of oak was 14'62 per cent., and that from the pedunculated 

 variety was 14'13 per cent, of tannin. More bark was not obtained 

 from the trees which were closely planted than from those planted 

 so as to give free scope to the solar rays, the same area therefore 

 containing fewer trees. Digging of the ground between the trees 

 was favourable to their growth, though the financial results of this 

 operation were not tabulated. The Quercus R. sessilijlora thus 

 appears the best oak to cultivate for tanning products. 



