300 
HERON OF ALEXANDRIA 
Pappus goes on to say that he will give four solutions, one 
of which is his own; the first, second, and third he describes 
as those of Eratosthenes, Nicomedes and Heron. But in the 
earlier sentence he mentions Philon along with Heron, and we 
know from Eutocius that Heron’s solution is practically the 
same as Philon’s. Hence we may conclude that by the third 
solution Pappus really meant Philon’s, and that he only men 
tioned Heron’s Mechanics because it was a convenient place in 
which to find the same solution. 
Another argument has been based on the fact that the 
extracts from Heron’s Mechanics given at the end of Pappus’s 
Book VIII, as we have it, are introduced by the author with 
a complaint that the copies of Heron’s works in which he 
found them were in many respects corrupt, having lost both 
beginning and end. 1 But the extracts appear to have been 
added, not by Pappus, but by some later writer, and the 
argument accordingly falls to the ground. 
The limits of date being then, say, 150 B.c. to a. d. 250, our 
only course is to try to define, as well as possible, the relation 
in time between Heron and the other mathematicians who 
come, roughly, within the same limits. This method has led 
one of the most recent writers on the subject (Tittel 2 ) to 
place Heron not much later than 100 b.c., while another, 3 
relying almost entirely on a comparison between passages in 
Ptolemy and Heron, arrives at the very different conclusion 
that Heron was later than Ptolemy and belonged in fact to 
the second century a.d. 
In view of the difference between these results, it will be 
convenient to summarize the evidence relied on to establish 
the earlier date, and to consider how far it is or is not con 
clusive against the later. We begin with the relation of 
Heron to Philon. Philon is supposed to come not more than 
a generation later than Ctesibius, because it would appear that 
machines for throwing projectiles constructed by Ctesibius 
and Philon respectively were both available at one time for 
inspection by experts on the subject 4 ; it is inferred that 
1 Pappus, viii, p. 1116. 4-7. 
2 Art. ‘ Heron von Alexandreia’ in Pauly-Wissowa’s Eeal-Encydopiidie 
tier class. Altertumsivissenschaft, vol. 8. 1, 1912. 
3 I. Hammer-Jensen in Hermes, vol. 48, 1913, pp. 224-35. 
* Philon, Mech. Spit, iv, pp. 68. 1, 72. 86.