130 
Fourth Law.—That when the azimuth of incident polari- 
zation exceeds the circular limit, and recedes from it, the ratio 
of axes again increases from unity. 
Fifth Law.—That when the azimuth is less than the cir- 
cular limit, the major axis moves always in the same direction, 
passing through the plane of incidence, when the incidence is. 
the principal incidence. 
Sixth Law.—That when the azimuth is greater than the 
circular limit, the axis major moves towards the plane of inci- 
dence, reaches a minimum, and turns back,—passing through 
the plane perpendicular to plane of incidence at principal inci- 
dence; and as the angle of incidence increases, the major axis 
describes a minimum on the other side of perpendicular, and — 
returns to a position at 90°, making an equal angle with that 
at which it set out, and at the other side. 
Rev. Mr. Jellett made some observations on this commu- 
_ nication, pointing out the great value of Mr. Haughton’s ex- 
periments. 
The following antiquities were presented by Joseph Hu- 
band Smith, Esq. :— 
1. Stone urn, found in a tumulus at Dunadry, county of 
Antrim, in 1837. 
2. Two fragments of rings, one of glass, the other of jet, 
found in the same place. 
3. Portion of large stone hammer, found in Island Magee, 
county of Antrim. 
4. Ball of green glass, found in a bog near Clogher, county 
of Tyrone. 
5. Small globular glass bottle, found at Slievegullion, 
county of Armagh. 
6. Fourteen ancient glass beads, found in the county of 
Antrim. 
7. Double glass bead, purple. 
8. Silver globular bead, ornamented. 
ae 
