MR. BACKHOUSE asks if the observations given in vol. iii. p. 203, afford any proof that the Zodiacal Light is not a lens-shaped disc of light enveloping the Sun; if this theory were correct, and the sun enveloped in a continuous mass of light-reflecting matter, whenever the light is seen in the evening after sunset, it ought to be also seen in the morning before sunrise, of the same brilliancy at the same angular distances from the sun, especially when those distances are small, for then the effect of an elliptical form in the section of the envelope by the plane of the ecliptic would be almost entirely eliminated.