Professor Gerlach has devised a means whereby the embryo growth in a bird’s egg may be watched. The end of the egg has a round hole cut in it; and by means of a kind of putty made of gum-arabic and wool, a pane of glass is inserted in the opening. This pane consists of a small watchglass, which is further secured in its place by cementing the outside of the joint with a suitable varnish. The egg so treated is put into an incubator in the horizontal position, and it can be removed and turned up for examination when required. A new kind of refrigerator has been devised, and is on sale in New York. The principle on which it acts is old enough, but the application of that principle is simple and interesting. An iron pipe two feet long and three and a half inches in diameter is filled with liquefied ammonia. To a stopcock at one end of this pipe is fitted a smaller pipe, which ultimately forms a coil within a cylinder about ten inches high and as many in diameter. This cylinder is made of wood and lined with hair-felt. The action of the apparatus is as follows: When the stopcock is turned on, the liquid ammonia rushes out in the form of gas, and absorbs so much heat that the temperature of surrounding bodies is immediately lowered. Any vessel placed within the coil inside the box can actually be lowered in temperature to sixty degrees of frost in a few minutes. Mr Price Edwards’s paper on ‘The Experiments with Lighthouse Illuminants at the South Foreland,’ recently read before the Society of Arts, London, was full of interest. In these experiments, the relative advantages of electricity, gas, and oil were put to careful test, temporary lighthouses having been erected for comparative trials of each. In the result, it was shown that in clear weather each illuminant was actually more brilliant than necessary. In dull and foggy weather the electric light penetrated further into the murky atmosphere than either gas or oil. But this extra penetration—amounting to two hundred or three hundred feet—is not of any practical importance to navigation. The final conclusion of the Examining Committee was: ‘That for ordinary necessities of lighthouse illumination, mineral oil is the most suitable and economical illuminant; and that for salient headlands, important landfalls, and places where a powerful light is required, electricity offers the greatest advantages.’ It may be noted as a matter of interest in the above-mentioned trials that the electric arc-lights employed were furnished with a novel kind of carbon rods, called the Berlin core carbons, and furnished by Messrs Siemens. These rods were fully an inch and a half in diameter, and were provided with a core of plumbago, or graphite, running through the centre. They were found to burn with exceptional steadiness, a result due to the superior conducting power of the central core.