2 
Proceedings of the Royal Society of Edinburgh. [Sess. 
means of Boyle’s Law. We are now, thanks to the wonderful measurements 
of Amagat, enabled to estimate pressures with great precision from the 
corresponding reduction of volume of air at any given temperatures. The 
data, so far as this point is concerned, were not quite fully given in 
Andrews’ paper, inasmuch as he had given the estimated compression 
of air only, the estimate being founded on a law now recognised as not 
rigorously correct. 
“ The second depended on a difference between the pressures to which 
the two gases were simultaneously subjected, arising from the fact that 
the common mass of compressing mercury stood at different levels in the 
two tubes. This difference, of course, varied with the stage of compression, 
being considerably greater throughout the ranges in which the carbonic 
acid was much more compressed than the air ; and less in those regions 
in which it was entirely liquid, and thus considerably less (further) 
compressible than air. 
.“Dr Andrews’ notebooks have been sedulously preserved, and on a 
careful examination I found that they afford the means of almost 
completely supplying Professor Tsuruta’s desiderata. Miss M. K. Andrews 
has kindly undertaken the laborious task of collecting, copying, and 
arranging them in the form in which they appear below. She is specially 
qualified for this work by her familiarity with her father’s handwriting, 
especially in the matter of figures; and I think it barely possible that 
any mistake due to that cause will be found.” 
Here the manuscript ends ; but I should like to supplement the last 
sentence by the remark that Miss M. K. Andrews has, in addition to her 
familiarity with the symbols, a clear knowledge of the whole scope of 
the enquiry, even to the details of corrections for tube-ends, capillarity, 
temperature, and so on. Under her guidance I went carefully through 
all the notebooks covering the experiments on carbon dioxide. Verbatim 
copies were made of many parts of these, full indexes were prepared, and 
everything done to facilitate the accurate comprehension of every record. 
It was at times no easy matter to dig out the meaning of some of the 
records, but, on the whole, once the clue was found the interpretation of 
the experimental jottings was not difficult. During the process of eluci- 
dation, however, it was borne in upon me that Professor Tait’s plan of 
reproducing the data might, with advantage to all interested, give place 
to another method. It seemed desirable to present the data in a form at 
once intelligible to the reader rather than compel him to go through the 
labour of ferreting out the meaning for himself. Moreover, the form in 
which the data now appear below is much more economical as regards 
