PROCEEDINGS. 
515 
319th Meeting. April 28, 1888. 
President Mallery in the chair. 
Twenty-five members and guests present. 
The President announced to the Society the death of Thomas 
Hampson, on April 28, and that of Emil Bessels, on March 30, 
1888. He also announced the election and acceptance to mem¬ 
bership of Robert Bowne Warder. 
The following communications were presented: 
On the Origin of Primary Quartz in Basalt, by Mr. J. P. 
Iddings. [Published in the Am. Jour. Sci., vol. 36 (3. s.), 
p. 208 .] 
Some Peculiarities in Personal Equation, by Mr. J. R. East¬ 
man. 
[Abstract.] 
In general, transit, observers who use the chronograph may be divided 
into two classes: First, those who make their record an appreciable time 
after the phenomena, and, second, those w T ho intend to have their record 
effected at the instant the transit takes place, and therefore necessarily 
begin the process of making the record before the star reaches the transit 
thread. In the case of the first, class the observer waits until he sees the 
star bisected by the thread and then makes his record, which occurs 
always later than the time of actual transit. The magnitude of this error 
depends upon the times required by the brain, nerves, and muscles and 
by the recording apparatus to act. For the same recording instrument 
the instrumental time is the same for all observers. The variability is 
due to the brain, nerves, and muscles. For all stars except very faint ones 
the error of the first class of observers does not seem to vary. So far as 
investigations have been carried, it is found that the errors of the second 
class of observers vary with the magnitude of the star. Large stars are 
observed earlier than small ones ; so that if a large star precedes a small 
one, the observed interval is too great; if the order is reversed, the interval 
is too small. 
Such work introduced into a fundamental catalogue would vitiate the 
results, and it would be impossible to determine the ultimate effect of 
such work without knowing the exact amount of error introduced by each 
observer. A discussion of the grouping of the large stars in every funda¬ 
mental catalogue leads to the conclusion that it is more than probable that 
a large portion of the catalogue errors, whose elimination is attempted by 
