NEW DATA FROM TESTS ON GLACIAL BRICK CLAYS 865 



In 1920-1921 A. J. Collins, for his thesis, made a study of clays from 

 Blakeley's pits on Holyoke Street, Lynn — latitude, 42° 28'; longitude, 

 72° 58.8' — about 500 yards from the Saugus Eiver. 



A and B were gray oxidized clays, respectively 4 and 10 feet below the 

 surface. 



C and D were blue, more plastic clays, respectively 4 and 13 feet below 

 the surface. 



The analyses were all computed water-free in this undried clay, direct 

 from the pit, but the per cent of water was also determined. Moisture 

 was determined in weighing tubes and ignition loss in a porcelain 

 crucible. 



Students' tests on samples, taken at the same time and of varying dry- 

 ness, gave from 1.69 to 2.18 tons per cubic meter, with the best value 1.78. 



Sample A 



A B 



Percent. Percent. 



Silica 60.79 60.74 



Ferric oxide 5 . 11 5 . 14 



Ferrous oxide 1 . 42 1 . 41 



Alumina 17 . 78 17 . 73 



Titanium oxide 1 . 1 . 01 



Lime 2.05 2.08 



Magnesia 3.20 3.22 



Soda 3.16 3.14 



Potash 6.33 6.37 



100.84 100. S4 



Moisture 2 . 82 



Ignition loss 4.27 to 4. 19 4.23 



Per cent of HX> in undried clay direct from pit 15.97 



Sample B 



A B 



Percent. Percent. 



Silica 60.58 60.60 



Ferric oxide 5 . 34 5 . 31 



Ferrous oxide 1 . 88 1 . 87 



Alumina 14.70 14.76 



Titanium oxide 90 07 



Lim e 2.47 2.50 



Magnesia 2.80 2.78 



Soda 3.61 3.66 



Potash 7.78 7.82 



100.12 100.27 



