PLATE 8.

Fig. a.

Fig. b.

Fig. c.

Fig. d.

Transverse section of the wood of Araucarioylon noveboracense,
showing the persistent leaf trace. X 15.

Tangential section of the seedling stem of Agathis australis. X 60.
Another of the same further out in the wood. X 60.

Longitudinal section through the pith of a trunk of Araucarioxylon
noveboracense. X 8.

Fig. e. Longitudinal section of an undescribed species of Araucarioxylon from New Jersey, showing the region of the pith. X 15.

Fig. f. Part of the same more highly magnified. X 40.

PROC. AMER. ACAD. ARTS AND SCIENCES VOL. XLVIII

Proceedings of the American Academy of Arts and Sciences.

VOL. XLVIII. No. 14.-JANUARY, 1913.

THE ACTION OF SULPHUR TRIOXIDE ON SILICON

TETRACHLORIDE.

BY CHARLES ROBERT SANGER AND EMILE RAYMOND RIEGEL.