265 
of correction for the self-registering thermometric observations were 
shown to be even more faulty than those used for that of the dry- 
bulb; firstly, from the circumstance that the faulty dry-bulb mean 
was held to be the only true mean, and made the basis for the cor- 
rection of the self-registering mean ; and secondly , from the circum- 
stance that the whole of the self-registering observations were made 
with Six’s registering thermometer, an instrument now considered 
inaccurate. By a reference to the Makerstoun Observations for a 
period of three years, and to those of Scotland for the last two 
years, it was demonstrated that, when the self -registering thermo- 
meters are of proper construction , the strict mean of the maximum 
and minimum readings appear to require no correction whatever, 
but indicate the true mean temperature. Particular attention was 
directed" to the Makerstoun Observations for 1844, when hourly- 
readings were taken with the dry-bulb thermometer, their strict 
mean giving the mean annual temperature as 44°9, while the strict 
mean of Rutherford’s self-registering thermometer gave the annual 
temperature as 45°0, than which no results could be closer. 
In the present state of the science, the author contended that the 
only safe rule for the estimation of mean temperature was to take 
the strict mean of the self-registering thermometers, provided these 
were of proper construction ; and he strongly denounced the practice 
followed in England, of withholding the strict means of the different 
series of dry and wet bulb readings, and only publishing deductions, 
which the facts brought forward in his paper proved must, in most 
instances, be erroneous. 
3. Description of the Plant which produces the Ordeal Bean 
of Calabar. By Professor Balfour. 
After noticing the various plants used in Africa as ordeal poisons, 
the author gave an account of the introduction of the Calabar Ordeal 
Bean into Scotland, by the Rev. W. Waddell, and mentioned its 
peculiar poisonous qualities, as determined by Dr Christison. To 
Dr Hewan, and the Rev. Zerub Baillie, who are connected with the 
United Presbyterian Mission in Old Calabar, he was indebted for 
some observations on actual cases of poisoning in Africa. The Rev. 
vol. iv. 2 N 
