140 IOWA ACADEMY OP SCIENCE 
Not long after the completion of well (2) an examination of well (1) 
showed that it had been filled to a distance of 800 feet from the bottom 
by caving shale. Attempts to clear the bore of this material proved 
nnavailing. What was left of the casing conld not be drawn or cnt out. 
Small sections of it were obtained and were found to be thin and full of 
holes. The well was abandoned and a new one begun in 1905. Soon 
after the completion of well (3) the capacity of number (2) became 
rather suddenly much reduced, and an examination showed the same 
difficulty as in number (1) ; that is, the caving of shale. The well was 
cleared to about 1,600 feet, where seemingly insuperable difficulties were 
encountered and the well was also abandoned. 
It was now evident that to continue to drill and abandon wells at this 
rate would prove a very serious tax on the resources of the city, and that 
some radical changes should be made in the casing of such wells. The 
casing should evidently extend below the shale that had caused trouble 
by caving, and the desirability of securing more durable casings became 
evident. So far as known to me the idea of a cast iron casing originated 
with Mr. Henry Simmon, at that time the city engineer. He talked with 
the writer from time to time, and as the idea finally developed, it was 
to sink a casing to just above the St. Peter sand-stone, 1,700; and to 
fill the space between the tube and the walls of the well with cement. 
Of course, his opinion gained from much practical experience, was that 
cast iron tubing of good quality would outlast iron tubing several times. 
This, in fact, seems to be the common experience, but one who under- 
takes to find proof of the great durability of cast iron over wrought iron, 
as deduced from scientific experimentation, will find difficulty. The lit- 
trature is full of comparative tests of the relative durability of wrought 
iron and steal, when exposed to water or the soil. This is probably 
owing to the great practical importance of the matter in relation to 
boiler construction. There seems to be very little on the comparative 
corrosion of wrought iron and cast iron. -The data, such as we have, 
are somewhat confiicting, but on the whole indicate that cast iron will 
outlast wrought iron two to four times. Cast iron seems to have excep- 
tional ability to hold a pitch enamel, which may extend its durability 
far beyond the above figures. ■ . 
The original intention was to case well (4) with cast iron tubing to 
1700 feet and the contract with the J. P. Miller Artesian Well Company 
of Chicago was so drawn. But, great difficulties were encountered when 
the attempt was made to ream out the lower part of the drilling. Shale 
caved from above, tools were fastened and some of them were broken 
away. For several months work was discontinued and there was some talk 
