Miscellaneous Intelligence, 83 
delicacy of texture or grace of motion; and even one who has 
never seen a living Ctenophore, may study their structure in 
as he is a biologist, and we cannot close without congratulating 
him most heartily on the publication of this model monograp 
A. AG. 
10. The Spiral Character of Celenterate Development.—Pro- 
fessor Joun Youne, in the number of the 
of Natural History for March, 1880, argues from the order of 
Ill. MiscentaNneous Screntiric INTELLIGENCE. 
1. Some incidental results from a series of analyses of air, 
made at Hudson, Ohio; by Epwarp W. Mortey.—The samples 
were taken daily, and at a regular hour. They were analyzed in 
duplicate. The greatest difference between the results of analyses 
of the same sample was ‘016 per cent. The probable error of a 
Single determination was less than ‘003 per cent. 
: e mean propertion of oxygen to the sum of oxygen and 
nitrogen for the first half of the year 1880 is as follows: January 
20, ‘951; February 20, 935; March 20, ‘949; April 20, 950; May 
20, 949; June 20, 951; January to June 20, -949. 
_ (2) Uncertainties in callibration, errors of observation and man- 
ipulation, and variations in the uantity to be measured, make the 
probable error of the final mean less than -002 per cent 
(3) Any given sample of air was as likely as not to differ from 
the mean of -012 per cent. 
(4) The probabilities are about ten to one that the differences 
between the means for any two months are within -002 per cent 
of the truth. 
(5) The largest proportion of nitrogen yet noticed was on De- 
cember 29th, 1879, when three analyses of the same sample gave 
21-045, 21°045, 21°044. The largest during the six months men- 
tioned was March 9th: 21-001, 21-006. 
(6) The lowest yet found was on February 26th, 1879, when, 
with another apparatus, there was found 20°45 and 20°50, The 
lowest during the six months was on February 14th, when one 
sample gave, 20°896 and 20°903; another sample gave 20°867. 
