In Paris and elsewhere (as in Holborn, for instance), each Jablochkoff lamp is enclosed in an opal glass globe. Mr. Hepworth remarks on this, that in his opinion the use of the opal globe is a mistake, as it shuts off quite 50 per cent. of the light without any corresponding advantage, except the correction of the glare. 'This wasteful disadvantage will no doubt be remedied in the future,' he says, by the use of some less dense medium. 'Mr. Shoolbred states that from a series of careful photometric experiments carried out by the municipal authorities with the Jablochkoff lights, each naked light is found to possess a maximum intensity of 300 candles. With the opal globe this was reduced to 180 candles, showing a loss of 40 per cent., while during the darker periods through which the light passed the light was as low as 90 candles. It may be mentioned here that Mr. Van der Weyde, who has long used the electric light for photographic purposes, has given much attention to the important problem of rendering the electric light available as an illuminator without wasting it, and yet without throwing the rays directly upon the object to be illuminated. The rays are intercepted by an opal disc about four inches in diameter, and the whole body of the rays is gathered up by a concave reflector (lined with a white material), and thrown out in a flood of pure white light, in which the most delicate shades of tint are discernible. He can use any form of electric candle in this way. Only it should be noticed, before the employment of his method is advocated for street illumination, that there is a difference between the problems which the photographer and the street-lighter have to solve. The Jablochkoff candle, for instance, must be screened on all sides, and even above, when used to illuminate the streets. If its direct light is allowed to escape in any direction, there will be a mischievous and unsightly beam, and from every point along the path of the beam, the intensely bright light of the candle will be directly visible. Again: it is essential that whatever substance is used to screen the light should be dense enough to cause the whole globe to seem uniformly bright or nearly so. The only modification which seems available (when these essential points have been secured) is that the tint of the globe should be such as to correct any colour which the light may be found to have in injurious excess. We may, however, remark that the objection which has been often raised against the colour of the electric light can hardly be just--the injury to the eyes in certain cases arising probably from the strong contrast between the light and the background on which it is projected. For, as to colour, the electric light derived either from the glowing carbon or from incandescent metal is appreciably the same as sunlight.