SCIENTIFIC NOTES.

Globe, Volume IV, Issue 453, 26 November 1875, Page 3

SCIENTIFIC NOTES.

(Chamoers's Journal.')

The Royal Commission appointed to inquire into the great question of the relations of government to science and scientific education, have brought their years of inquiry to a close, and delivered their final report. They have taken a wide range, and heard many and divers opinions and statements ; but they have not been led astray by sanguine advocates of plausible theories. Build a great national laboratory, say some, furnish it with all needful appliances, and a host of experimentalists will resort thereto, and develop chemistry and natural philosophy, and make the nation rich, and themselves famous. The Commission have been slow to believe in the existence of cases of scientific genius pining for want of encouragement, and they have not recommended that a big laboratory should be build at Hie natioual expense. But they do recommend that elementary and advanced science should be taught in schools, and that scientific research should, under certain conditions, be aided by grants of money. Science deals with laws of nature and with facts ; hence, if education can be improved by the accurate methods of science, so much the better tor the educated. Recently, the worshipful Company of Spectacle Makers entertained the Astronomer Royal at dinner. In h's after-dinner speech, that learned gentleman told them there was but one man in London who knew how to make spectacles. The company have resolved that henceforth that reproach shall not be theirs, and we mav believe that in time a citizen and spectacle maker will know something about optics and the physiology of the eye. As everybody knows, there are some months of the year in this climate of ours in which we contrive to keep ourselves tolerably comfortable without sunshine. The convenience of being able to make use of an equivalent for sunshine is obvious, and is often exemplified in manufacturing operations. Even hop-growers have been known, in moments of despair, during a wet season, to lay armfuls of their precious plants before the kitchen fire ; but, with that exception, we have never heard of a substitute for sunshine in agricultural operations, until now ; and now, Mr W. A. Gibbs, of Chingford, Essex, has brought out a machine for drying hay by artificial means. With a portable stove and a swift fan he produces a blast at high temperature (four hundred degrees or more), and drives it into a long trough, down which the wet hay, or grass, slowly travels, continually stirred and shaken up by small levers, contrived for the purpose. The hot, dry air, rushing with velocity, at once licks off all the moisture, and converts ' partially made, but wet hay, into a thoroughly dry condition for the stack ;' and, as is reported to the Times by a competent onlooker, ' we saw spoilt and musty hay dried into hay of fair ap- I parent quality and pleasant fragrance : and | we saw freshly-cut grass, saturated with rain I from a very heavy thunder shower which poured down at the time, diied into hay of first-class color, and possessing the rich malt odour peculiar to well made hay.' The cost of converting fresh-cut grass into hay is two pounds per ton ; if partially dried by the weather, the cost is not more than seven or eight shillings per ton. The inventor of the machine is of opinion that, even in fine weather, the quality of the hay would be improved by a spell of the hot-blast. As regards the economy of the operation ; we are informed that there are in the United Kingdom about nine million acres of grass, natural and artificial ; tbat they produce twelve million tons of hay, worth, on the iverage, four pounds per ton. The amount and importance of the total value may thus oe easily seen ; and any reader materially

interested in the question may calculate the difference in value between hay properly dried and hay badly made under unfavorable circumstances. The late ' catching ' summer will have prepared many minds for a solution of the question. What to do with our sewage ? is still a difficult problem to answer, either from the urban or the agricultural point of view. General Scott, whose endeavours in connection therewith we have before noticed, has just published ' A Compendious Statement of the Nature and Cost of certain Sewage Processes,' which is full of practical suggestion, and well worth consideration. There are five ways in which sewage may be utilised : (') By irrigation of a farm, which will yield a small profit, say £3OO a year, for a town of 100,000 inhabitants ; (2) purification of the fluid waste by chemical means, involving the lime method of precipitation, and the manufacture of dry sewage manure ; (3) the cement process ; (4) the improved calcination and manure process. As regards the merits of theße several ways, we are told that ' each of the first two costs about fiveper head per annum for the population ; the third, in any town large enough to afford a market for cement, will yield an annual profit of nearly a penny per head ; and the fourth may be made to yield a profit of more than three times that amount — apparently the extreme limit to which, as a matter of finance, the utilisation of liquid sewage can be carried.' The fifth way which General Scott now puts forward bears a high profit. In this, the excretions are not mixed with water, but are kept separate and undiluted. The liquid portion contains ammonia, and the ammonia is valuable. It is possible to separate the liquid from the solid portion. The ammonia can then be separated from the liquid by a •'chemical process of extreme simplicity." The liquid is passed through a series of tauks in which is a layer of phosphate of magnesia. This phosphate absorbs the ammonia. In other tanks, lime is used to arrest the phosphoric acid, which otherwise would be carried away in solution, and the resulting ammonia-phosphate of lime is treated with sulphuric acid, which removes the ammonia, and the solution thus obtained is concentrated, and set aside to crystallise. The phosphate of magnesia having been washed clean by the operation here described, can be used over and over again a number of times; but in the form of ammonia-phosphate it can be readily sold at £2O a ton. Meanwhile, the solid part of the excretions has been dried and reduced to powder ; and General Scott proposes to fortify this powder with a small quantity of the ammoniophosphate, and so produce a fertiliser worth from £6 to £7 a ton. This method has been tried at Oldham with complete success, and measures are set on foot for its introduction into other towns. The annual value of the excreta collected in Manchester is at present £7OOO. We are told that it would be £177,000 under the new process, and that if the process were generally adopted, ' it would render this country independent of Peruvian guano, and at the same time lift an enormous load off the shoulders of urban ratepayers.' It would, moreover, prevent waste of money in unwise schemes, as, for example, in a town not forty miles from London where the scw&ge, at heavy cost, is pumped up a long hill to its outflow on a farm.

As our readers are aware, we have many times called attention to instances of the injurious effects on climate of the wholesale cutting down of forests. An interesting account, communicated some time ago to the Linnasan Society by Dr Shaw, furnishes an example of another kind, and shews us how the vegetation and climate of the wool producing region of the Cape Colony are being changed for the worse by 'a persistent and trreedy system of overstocking.' The region in question is known as the 'Midlands,' situate far in the interior beyond the Sneeuwberg range (or Snowy Mountains), and in the days of the first settlers was the pasture ground of thousands of antelopes and other auimals. which, following the rains, migrated from one end to the other. It is very different now. When first introduced, the sheep thrived so in that prairie-like laud that the settlers crowded it more and more with sheep. Soon the grass was all devoured, and plants and shrubs were attacked, and came to be the main resource of the Hicks. The ground was consequently left to bush and scrub, and to obnoxious and poisonous herbs, and the intoxicating AJeliece —the 'dronk' grass of the Dutch colonists.

'• The climate,' says Mr Shaw, 'necessarily became affected. The rainfall came down less certainly and oftener, in the form of thunder torrents. Side by side with the attacks of the flocks the more subtile and insidious agency of a changing climate came into power. The hardy plants of the Karoo commenced to travel northwards, and added their energies to the extirpating of the indigenous and proper flora of the region, and being of a bitter and nauseous character, they enjoyed immunity, and were only eaten by sheep in circumstances of dire necessity. Sweet bush, such as Lyciums, vanished before them; and the veld has become what is called by the farmers, and indeed is now, a " bitter veld," and is rapidly becoming an extension of dreary, scrubby half-desert Karoo.' Besides all this, the ground becomes harder, and the perennial springs weaker.

It is clear that if some remedial measures are not applied, this once prosperous region will become a wilderness. Dr Shaw is of opinion that the Cape Government should ' experiment on the introduction of grasses,' and, ' by the construction of colossal dams, save the country, keep up the deep springs, aud in connection therewith, rear the beginnings of forests, to modify and increase the rainfall.' Nothing stops the extension of the 1 wild Karoo,' as Barry Cornwall calls it, so effectually as permanent moisture. As Dr Shaw says in conclusion : ' It is certainly a übject of alarm to the country when it is known that a drier season than usual entails poverty and death to an incalculable extent among our flocks in South Africa. Some tracts of country are poisoned by the extraordinary increase of the Tripteris ffcxuosa ; and transport riders, with their oxen (oui only carrying power), have to travel through certain parts of the country without pausing, on account of the Milioce, grasses which have increased within the past few years to a degree scarcely credible, and on eating

I which cattle become intoxicated to an alarming extent.' Railway signals which work without the help of human hands seem to off or some assurance of safety that has so long been desired by travellers. It is known that the distance-signals, worked by long wires, are liable to get out of order, and that there is a limit to the distance at which they can be placed. Mr Spaguoletti, chief electrician to the Great Western Railway, has invented an electro-magnetic signal which is well deserving of attention, inasmuch as it can be worked at any distance—at two or ten miles, as well as a hundred yards. The ordinary out stretching signal arm, with which we are all familiar, is attached to a rocking lever between two electromagnets ; these are connected with a battery in the ordinary way, and contact can either be made by a signalman touching a key, or by the locomotive pressing down a treadle. For night service, colored lamps can be worked as readily as the signal arm. To an outsider, the numerous signals at a railway station appear confusing and complicated. If this elfctro-magnetic signal were taken into use, no other woald be required, and thus simplicity would come , into play. In cases the apparatus is worked by hand, a little copy of the signals in the signalman's box tells him whether the distant signal, far out of sight, is working properly or not. But, as before stated, the locomotive itself will set the signals; will leave a danger signal standing in the rear; will ring a bell to announce its approach; and, on arrival at the next station, lets down the danger signals first put up, raises the next, sends on the warning whistle, and so does all the signalling with the regula-ity of clockwork. Of course there must always be a sufficiency of battery power to keep the magnets up to their duty; if this be done, the signal post may be fixed in any place wherever it is likely to be most effective.