Put a lump of zinc into the boiler of a steam-engine, and it will prevent the formation of ‘scale;’ that is, the stony crust which, as all engineers know to their sorrow, is very injurious and involves constant expenditure. The experiment having been successfully tried during four years by certain manufacturers in France, the Minister of Public Works appointed a Commission to inquire into and report upon it. From their Report, which was published last year in the Annales des Mines, we learn that the zinc is to be placed in the boiler as far as possible from the furnace, the quantity being a quarter-pound for every five square feet of boiler-surface if the water be soft, and a half pound if the water be hard. The boiler is then worked in the usual way; and when opened for the usual cleaning the appearances as the Commission describe will be—‘If the water be but slightly calcareous, the deposits, instead of forming solid and adherent scale, are found in a state of fluid mud, which is easily removable by simple washing. The iron being clean and free from rust, no picking or scraping is needed, whereby an important saving of time and labour is effected.’
On the other hand, if the water be strongly calcareous or hard, ‘the deposits are as coherent and strong as though the zinc had not been employed; but this strong coat does not stick to the iron. It can be pulled off by hand, or at the worst detached without much effort, leaving the iron clean. A simple washing clears it from the boiler; and in this case, as in the foregoing, picking and scraping are avoided.’
Here the question arises—What has become of the zinc? The answer given is, that it is not strictly correct to say it has disappeared, for it has been transformed into oxide of zinc, a white and earthy substance, which often preserves the lamellar texture of the metal, the central part sometimes continuing metallic and unattacked. At the same time it is worth remark that no trace of dissolved zinc is found in the water taken from the boilers.
A communication to the Royal Institute of British Architects by Mr Penrose makes known certain important ‘improvements in paint materials invented by Mr W. Noy Wilkins,’ which have been satisfactorily tested in the decoration of St Paul’s Cathedral. In the words of Mr Penrose, ‘The results arrived at are of such extreme simplicity as to make their general application extremely easy, and also to give a strong a priori conviction of their permanence. In the matter of pigments, white-lead is entirely banished from the painter’s stock, and the substitution of kaolin, mixed with a smaller proportion of zinc-white, combined with the limitation of the palette to the mineral colours. Mr Wilkins has practised for twenty-five years exclusively with these materials.... His discovery is that the chemical driers, which produce a very unfavourable effect upon painter’s work, whether of the house-painter or the artist, causing it to darken and to crack, can be entirely dispensed with, by simply boiling for a short time a small quantity of Turkey umber in the oil to be used for painting—whether linseed, poppy, or nut oil—producing as desired a drying painting oil or a varnish, and the residuum forming a valuable oil cement.’ Mr Wilkins permits cultivators of art, desirous of more particulars, to address him at ‘The Cottage, Elm Grove, Peckham’ (London).
In another communication, by Mr I’Anson, on the Architecture of Norway, the wooden churches were of course mentioned, and something was said about Norwegian timber which will bear repetition. ‘The Scotch fir furnishes the red wood, and the spruce-fir the white. What strikes one,’ said the speaker, ‘is, that the Scotch fir, which with us is regarded as the least valuable kind of fir-wood, scarcely fit for railway sleepers or fences, is the best fir in Norway. I account for that superiority of the Norwegian over the English tree in some measure by the greater length of time that Scotch fir takes to come to maturity in Norway than in this country. Scotch fir grows at the rate of as much as two feet a year in Britain, and takes about fifty years to become a usable tree; whereas in Norway it would take probably a century to grow to a tree of equal size.’
In the last annual Report of the Royal Asiatic Society it is stated as a now nearly accepted fact, that the language of Madagascar is a Malay language from Sumatra, and that its connection with the African Suahili is only that of loan-words, just as Persian has borrowed largely from Arabic. Philologists and others interested in Eastern Africa will perhaps be glad to hear that a grammar of Malagasi has been recently published.
Plantations of the cinchona tree were first begun in Jamaica in 1860, at the cost of the government. The experiment has proved so successful that more than eighty thousand trees are now growing in different parts of the island. Henceforth the West Indies will compete with India in supplying the world with quinine.
It is well known that in some churches and large halls a reverberation prevails which annoys the persons assembled, and prevents their hearing distinctly. A few years ago the discovery was made that the reverberation could be deadened by stretching threads across the building from wall to wall below the ceiling. This curious fact has been further confirmed at the Palace of Industry, Amsterdam, and in the church of Notre-Dame des Champs, Paris, in each of which, by the simple means of threads, the reverberation is silenced.
The importation of fresh meat from the United States of America commenced in the autumn of 1875. Since then the quantity brought to this country from New York, Philadelphia, and other ports, has reached a total of more than sixty million pounds; and great as the trade has become, it tends to increase. The graziers and agriculturists of Europe will have to consider whether some means may not be found for increasing and cheapening cattle-food, if they desire to compete with the transatlantic graziers. Whether the way shall be by improved irrigation, extended drainage, or creation of pastures, remains to be discovered. On this subject much valuable information is contained in a work entitled Food from the Far West, with special reference to the Beef Production and importation of Dead Meat from America (W. P. Nimmo, London and Edinburgh).
‘On Some Means used for testing Lubricants’ is the title of a paper by Mr W. H. Bailey, read before the same Society. There needs no argument to prove that if it be possible to discover the oil or grease which will best prevent friction, it ought to be discovered; and the engravings in this paper shew the contrivances for effecting this discovery. To Dr Joule, F.R.S. all who use machinery are indebted for having, as Mr Bailey remarks, ‘enabled us to look upon the cost of friction and the cash value of heat as mere questions of arithmetic. The energy which passes away in wasted heat may be measured and valued with nearly as much facility as any article of commerce. The science of heat teaches us that the relations between heat and mechanical motion are regulated by well-defined, accurate, and rigid principles. Those who would command Nature’s forces must first learn her laws; the first rudiments of which say, that when we produce frictional heat in our machinery, we become law-breaking prodigals, who have incurred fines and penalties, which are generally paid when a cheque is given to settle the coal-bill.’