POLICIES effected in this Office do not become void through temporary difficulty in paying a Premium, as permission is given upon application to suspend the payment at interest, according to the conditions detailed on the Prospectus. Specimens of Rates of Premium for Assuring 100l., with a Share in three-fourths of the Profits:-- Age £ s. d. 17 1 14 4 22 1 18 8 27 2 4 5 32 2 10 8 37 2 18 6 42 3 8 2 ARTHUR SCRATCHLEY, M.A., F.R.A.S., Actuary. Now ready, price 10s. 6d., Second Edition, with material additions, INDUSTRIAL INVESTMENT and EMIGRATION: being a TREATISE on BENEFIT BUILDING SOCIETIES, and on the General Principles of Land Investment, exemplified in the Cases of Freehold Land Societies, Building Companies, &c. With a Mathematical Appendix on Compound Interest and Life Assurance. By ARTHUR SCRATCHLEY, M.A., Actuary to the Western Life Assurance Society, 3. Parliament Street, London. * * * * * ROSS'S PHOTOGRAPHIC PORTRAIT AND LANDSCAPE LENSES.--These lenses give correct definition at the centre and margin of the picture, and have their visual and chemical acting foci coincident. _Great Exhibition Jurors' Reports_, p. 274. "Mr. Ross prepares lenses for Portraiture having the greatest intensity yet produced, by procuring the coincidence of the chemical actinic and visual rays. The spherical aberration is also very carefully corrected, both in the central and oblique pencils." "Mr. Ross has exhibited the best Camera in the Exhibition. It is furnished with a double achromatic object-lens, about three inches aperture. There is no stop, the field is flat, and the image very perfect up to the edge." A. R. invites those interested in the art to inspect the large Photographs of Vienna, produced by his Lenses and Apparatus. Catalogues sent upon Application. A. ROSS, 2. Featherstone Buildings, High Holborn. * * * * * PHOTOGRAPHIC PORTRAITS and VIEWS by the Collodion and Waxed Paper Process. Apparatus, Materials, and Pure Chemical Preparation for the above processes, Superior Iodized Collodion, known by the name of Collodio-iodide or Xylo-iodide of Silver, 9d. per oz. Pyro-gallic Acid, 4s. per drachm. Acetic Acid, suited for Collodion Pictures, 8d. per oz. Crystallizable and perfectly pure, on which the success of the Calotypist so much depends, 1s. per oz. Canson Frère's Negative Paper, 3s.; Positive do., 4s. 6d.; La Croix, 3s.; Turner, 3s. Whatman's Negative and Positive, 3s. per quire. Iodized Waxed Paper, 10s. 6d. per quire. Sensitive Paper ready for the Camera, and warranted to keep from fourteen to twenty days, with directions for use, 11×9, 9s. per doz.; Iodized, only 6s. per doz. GEORGE KNIGHT & SONS (sole Agents for Voightlander & Sons' celebrated Lenses), Foster Lane, London. * * * * *