rg1t] DACHNOWSKI—CRANBERRY ISLAND 133 
periods of time as were necessary to make a reading. For strata 
nearer the surface differential and ordinary mercurial thermome- 
ters were used, the bulbs of which were pushed down into the peat 
around the rhizomes of the plants to a depth of one foot (20 cm.) 
and three inches (7.5 cm.), respectively. The glass stems of the 
exposed instruments remained shaded from the direct rays of 
light. The temperatures recorded below, in centigrade, were 
generally taken on afternoons, usually between 12 and 2 P.M. 
It should be kept in mind that the maple-alder zone conditions 
correspond very nearly to those of the tamarack-willow-poplar 
zone of the northern bogs and swamps, and that a similar relation 
exists between the local central zone and the open bog-sedge zone 
of northern bogs. 
The readings taken during the period of observation are too 
voluminous for a tabulated record. Only those of the seasons of 
1909 will be given in this place (table V). 
TABLE V 
TEMPERATURES (C.) IN THE PEAT SUBSTRATUM OF CRANBERRY ISLAND 
SEASON OF I909 
: ‘ Aug. | Sept.| Oct. | Nov.| Dec. 
Station ee ee ee 
Central (sphagnum- 
cranberry) zone: 
Art. ¢ic 6.5 {5 tA 124. 6|24° (20> (94 es 487 F-54365 
Air 36 cin 5 Ors 14.5 th (og 195. 20 ee 8 a7 7 ae 25 
Al 7. ¢ Om... 32. 1.0 (425 [84.5122 (26° 20 jaesSiz6 127.517 ita | 25S 
bol 7 Scan. O.8 10.5 Tre 1s ee Sit. Seek aS S27git0 1 fF  ) O.§ 
Soil 30 cm. O.5:19,051 7. 130. Ste2 iat Ol2a 2125. 129.5117 8 2,5 
ES SO 7.5 (6.3 | 8.5| 9 |x |16.0j21 |22 |22.5/21.5|16.5|13.0 
Maple-alder zone: 
OS 6 On O15. 12 tt |xt (136 120° (20.522 (20 [14 | 8 
SO 30 Mii. 1.5 12.0 |) o.5ix ta [tO 819% (27. 5/20: 135-5 5 
OOH Fb Mi. 6.5 |§.0.| 8.0|/10.5|14 |17.5]/10.5/21.5/21 [19 |15.5/14 
Lake zone: 
‘Water 7.6 cm... 23. C5 ir 13.5|14.5|20.5|26 |29 |28.5/25 |15 |6.5 | 3.5 
Water 30 cm....... 1.5 |0.5 |13.5)14. 5/2 G lag. (28 -bias 11s 16.5 1 4 
Water ¢.9 m:... 1.1 |2.7 |t3 |13.8|18.8|22.5/26 |26 |24 |12 |6.5| 5 
A glance at table V shows that the temperature conditions, 
though comparatively uniform and high throughout the bog island, 
range somewhat lower in the maple-alder zone than in the central 
