136

External temperature: -12°C
Room temperature at the gas measurement locations: -6 to -8°C
Measured gas concentrations

 1st
measurement
location
 2nd
measurement
location
after 1 hour 4,48 g HCN9,80 g HCN
" 2 hours6,36 g " 8,00 g "
" 3 " 5,77 g " 6,80 g "
" 4 " 4,86 g " 5,40 g "
" 5 " 3,78 g " 4,30 g "
" 6 " 3,30 g " 3,70 g "
" 7 " 2,80 g " 3,10 g "
" 8 " 2,50 g " 2,60 g "
" 10 " 2,00 g " 2,00 g "
" 24 " 0,70 g " 0,60 g "
" 48 " 0,15 g " 0,15 g "

2. Barracks building B (economics building), area 4311 cbm
Zyklon consumption 43.2 kg CN = 10 g/cbm
Gas applied 20 January 1941, morning 10:15
External temperature +6 to +9°C
Room temperature at the gas measurement locations: -4°C (cellar), -5°C (upper ground floor)
Measured gas concentrations

 1st
measurement
location
 2nd
measurement
location
after 1 hour 2,32 g HCN4,59 g HCN
" 2 hours3,56 g " 5,24 g "
" 3 " 4,21 g " 5,35 g "
" 4 " 4,32 g " 5,29 g "
" 5 " 4,37 g " 5,24 g "
" 6 " 4,21 g " 5,02 g "
" 7 " 4,00 g " 4,75 g "
" 8 " 3,82 g " 4,60 g "
" 24 " 1,51 g " 1,51 g "

From these analytical values, the following can be derived:

1. In all cases, the essential part of the disengagement of the gas is complete after one or at most two hours. (A control of the residues at the applicable times confirmed their complete degassing.) The evaporation of the prussic acid was therefore not significantly delayed by the low temperature.

2. The obtained concentrations of gas did not distinguish themselves considerably from those achieved in buildings of a similar nature and measured on earlier occasions.

That, in addition, the dispersion and reaction of the gas in the given temperature conditions were sufficient at a normal dosage of 10 g prussic acid per cbm was confirmed through suitable biological controls. All test specimens, set out at various elevations, that were removed from the gas after 24 hours were without exception 100 per cent killed, including the most resistant larva phases.

Experiments in the laboratory

In the current apparatus that has already been described many times, the most highly resistant bugs and bug larvae