159 MR. Gs ERDTMAN : STUDIES iN THÉ 
chemical examination. For taking levels and measuring sections I used a 
Tesdorph tube. The very short time at my disposal did not allow of such 
measurements, or of analyses of the recent peat-moss vegetation. For these 
a simple folding wooden square of 1 sq. m. is used (ef. Du Rietz, 1021, 
fig. 20). 
b. The Field Work proper. 
After making trial borings, a bore is made in the most representative spot, 
at first to a depth of 50 cm. The container of the bore has a length of 
30 em., and we thus get a peat core of this length. As a rule two samples 
are to be taken from every core, which, in this case, would come from a 
depth of about 25 and 45 cm. below the surface of the peat moss. Next, 
borings are made to 100, 150, 200 em., ete., below the surface. In some 
cases, especially when dealing with sediments or with peat which has taken 
a very long time to form, it is better to take 3 to 5 or more samples from every 
core, also to make borings every 25 em. When these manipulations are 
carried out with due cleanliness, there is no risk of getting dirty specimens. 
However, if there are peat-hags or cuttings in the neighbourhood, these are 
to be preferred. Such sections seem to be more common in Scotland than in 
Sweden, partly owing to the greater shallowness of the Scottish peat. (For 
a more detailed description, see Erdtman, 1921, pp. 15-16.) 
B. The Laboratory Work. 
When making preparations for mieroscopical examination, a very small 
amount of the samples taken from each end of the peat pillar and enclosed 
in the little glass tubes is laid on a slide and boiled with 10 per cent. 
caustic potash (KOH) *. When the greater part of the water has evaporated, 
a drop of glycerine is added. A part of the cooked substance is then laid 
on another slide and covered with a cover-glass. The pollen-grains are then 
counted by the use of the micrometer stage of the microscope, and for each 
specimen analysed I write a record ; for example, the following :— 
13. x. 1923. 167 (Skye). 
AINUS .......,.. 19= 11 per cent. Tetrads of Ericaceæ. 
Betula .......... 130= 74 per cent. Sphagnum spores. 
Pinus .......... l4= 8 per cent. Grass pollen. 
Quercus ........ 5= 3 per cent. Filicinean spores without exosporium. 
Ulmus .......... 7= 4 per cent. “Fragments of needles of sponge. 
TTT Nuphar pollen. 
c Total ...... 175—100 per cent. Polypodium vulgare (spore). 
orylus ........ 1=sporadie. Glwotrichia sp. 
PF (pollen frequency) =560 (0*6). 
* Minerogene earths are often better treated with HF] (compare Assarsson and 
Granlund, 1924). 
