DOA AL ANNUAL REPORT 
Per cent. ] 
STV ay evga tae eas ete ea oe ape eae te ACE 63.26 
yaUUUNO CU) dv: Wen eae cM Pama sa a CNS galas Sgn SE ine 22.70 
FerriG. OX ak sine hae Nae cee eT Se ae ee) 
Loss On 1g nitio mings Sea erence Cae ter ew ieee re an 6.52 
97.68 
IRGO ISNO), 8 ALOR, 8 82.73 3 A 
This mill was in operation for a number of months, but did not suc- 
ceed in burning satisfactory cement. The heavy financial losses caused 
the plant to pass into other hands. ‘There is no reason whatever to believe 
why, with an addition of free silica in some snaee the clay would not 
have produced a good cement. 
Professor Edward Orton, Te, in investigating certain limestone ma- 
terials for Portland cement purposes found that the alumina was already 
high enough, while the silica required an increase. This he introduced in 
the form of finely ground sandstone, instead of the clay usually employed. 
The cements resulting from this mixture proved slow setting, requiring no 
addition of gypsum, but after 28 days showed an extraordinary strength, 
about 20 per cent higher than the best commercial cements. 
Blaese* was compelled to work a clay of the composition: 
Per cent, 
LTC are aoc heer et eh eee Ie ne IR oh em Ne eee gn ap 58.19 
AN UTTMAE, BWC! HAE ONICWs . ssccccasodoccnosavcecaovce 26.11 
| Ei) aay are ep nA Men Ay aR Sane RAEN hat cate bn tae i eh ee a 0.78 
Miaeies aye eek ok oe a een cee at errands eee era 2.41 
Loss omiugnitione «satire Was eeeweee eo eran ar erie ee are 6.69 
94.18 
The cement in spite of an addition of 2 per cent. of gypsum set in 2 to 
3 minutes and showed decided “blowing” tendencies, so much, in fact, 
that barrels of cement were bursted, due to the expansion, in spite of the 
fact that a series of compositions was made so as to determine the best 
mixture. In this difficulty, this chemist added sea sand to the clay and 
succeeded in producing a cement of excellent quality. However, it is 
interesting to note that an addition of 0.5 per cent. of fluorspar to the raw 
mix also produced a good cement. This last fact does not help out the 
statement made above nor does it tend to refute it. 
Prof. E. D. Campbell,** of the University of Michigan, has likewise 
found that lean clays, high in silica, are safer than aluminous clays. 
In examining a clay analysis it is always to be recoramended that the 
formula be calculated from it on the basis that alumina is taken as unity. 
*Tonindustrie Ztg. 1896, No. I. 
** Journal Amer. Chem. Society, 1902, No. 10. 
