Dr Morton on the Size of the Brain. 333 
tables. 1 have once and again tested the accuracy of this 
process, by experiment, in the lower animals, and have thus 
perfect confidence in the accuracy of its result, be the pro- 
blem to recover the weight of the encephalos, from the 
cranium of a sparrow or from the cranium of an elephant. 
“IT may conclude by saying, that I have now established, 
apart from the proof by averages, that the human encephalos 
does not increase after the age of seven, at highest. This has 
been done, by measuring the heads of the same young per- 
sons, from infancy to adolescence and maturity ; for the slight 
inerease in the size of the head, after seven (or Six), 1S ex-~ 
hausted by the development to be allowed in the bones, 
muscles, integuments, and hair.” 
Analysis of the Anthracite of the Calton Hill, Edinburgh. 
By Dr A. VoELCKHR, Professor of Chemistry in the 
Agricultural College, Cirencester. Communicated by 
the Author.* 
We are in possession of analyses of anthracite from seve- 
ral localities, and we have learned by them, that the composi- 
tion of this mineral, like that of coal, varies very much ac- 
cording to the locality where it is found; so that there are 
scarcely two localities which furnish anthracite of exactly 
the same composition. 
All samples of anthracite which have been analysed, have 
been found to contain carbon, hydrogen, oxygen, nitrogen, 
and more or less inorganic matter, as well as sulphur (at 
least where it has been looked for), in a proportion which dif- 
fers but slightly from that in which it occurs in common coal. 
Generally speaking, the per-centage of carbon is larger in 
anthracite than in common coal, whilst hydrogen predo- 
minates in the latter; and we find, likewise, that the more 
the anthracitic character of a sample is pronounced, the 
* Read before the Royal Society of Edinburgh, 4th Mareh 1850, 
