Inventors of gas apparatus should note that the municipal authorities of Brussels have decided upon holding a competition, with a view to ascertain the best means of using gas for heating and cooking purposes. A large sum is to be offered in prizes to the successful competitors. Apparatus for trial must be forwarded not later than September next, and all particulars regarding the matter may be obtained from the chief engineer, M. Wybauw, Rue de l’Etuve, Brussels. In the island of Skye, large deposits of the very useful mineral called diatomite have recently been found. Under the German name of _kieselguhr_, this absorbent earth has been extensively used in the manufacture of dynamite, which consists of nitro-glycerine rendered more safe for handling by admixture with this porous body. It is also used as a non-conducting compound for coating the exterior of steam-pipes and boilers, as a siliceous glaze for pottery, for the manufacture of silicate paints, and for many minor purposes. In this particular deposit the varieties of diatoms are singularly few, only sixteen species of these wonderful microscopic organisms being represented. The deposit is estimated to yield a total of between one and two hundred tons. At a recent meeting of the Royal Society of Edinburgh, Dr A. B. Griffiths read a most instructive paper on ‘The Effect of Ferrous Sulphate in destroying the Spores of Parasitic Fungi.’ The value of this salt—the common ‘green vitriol’ of commerce—as a plant-food has long ago been established; but Dr Griffiths points out the important antiseptic property it possesses in destroying certain low forms of plant-life. As a preventive of potato disease, it is most effectual, although the spores of that fungus possess such vitality that they may be kept as dry dust for eight months without losing their power for mischief. Dr Griffiths also notes that in damp warm weather, the potato disease is actually encouraged by the use of potash manures. He advocates the treatment of manure with a weak solution of the iron salt before its application to the land. Wheat when treated with the sulphate is rendered proof against mildew.