June 1st, 1887.] 



SCIENTIFIC NE^VS. 



93 



THE ROYAL INSTITUTION. 



LIGHT AS AN ANALYTICAL AGENT. 



AT a recent lecture, given by Professor Dewar, he .said that 

 many questions arose in the progress of research which 

 were perhaps to be considered rather as side issues than actually 

 coming in due sequence. Thus there were two conditions of 

 study — the action of light on matter, and the action of matter to 

 produce light. The latter, as was known, could be effected in 

 many different ways, but the recent methods by which the action 

 of light on matter had been studied had shown that light was 

 such an exceedingly refined agent that it was doubtful how it 

 would have to be regarded in future. In effecting some decom- 

 positions, its action appeared to be instantaneous. Among the 

 many puzzling problems that had lately arisen were those in 

 connection with electric discharges in high vacua. When carbon 

 was used as an electrode, a carbon compound was the result, but 

 the question was. Where did the o.xygen come trom? Could it 

 be that it came from the glass ? Many most interesting conclu- 

 sions had been drawn from vacuum tubes, but a most important 

 consideration was whether what was seen was rightly inter- 

 preted. Again, much reliance was placed on the spectra of 

 bodies to tell us of changes they underwent ; but, after all, what 

 were the spectra, and what were the molecular changes of which 

 the spectra were the result ? The path in which it was hoped, 

 perhaps, to find some answers was that of Stass, of Brussels. 



THE SOCIETY OF ARTS. 



THE CHEMISTRY OF PUTREFACTION. 



IN the second Cantor lecture on this subject given by Mr. 

 J. M. Thomson, he said Ammonia is produced in the de- 

 composition of organic substances containingnitrogen, whilst sul- 

 phuretted hydrogen and carbonic acid are also common products 

 of decomposition. When coal is subjected to dry distillation, all 

 these bodies are formed. Animal substances contain frequently 

 the element phosphorus, in addition to those mentioned. Animal 

 matter undergoing decomposition produces what are known as 

 ptomaines. They are poisonous nitrogen bases, similar to the 

 vegetable alkaloids, and can be recognised by the same general 

 tests. Iodine, dissolved in iodide of potassium solution, gives a 

 distinct precipitate of the alkaloid itself. Hair, wool, nail, and 

 horns also yield large quantities of ammonia, as a result of their 

 decomposition. Hydrogen is also liberated under certain con- 

 ditions of decay, and at the moment of its liberation is capable of 

 reducing phosphorus compounds, and forming with them phos- 

 phoretted hydrogen, a gas which is characterised by phos- 

 phorescence ; and it is, therefore, probable that the phos- 

 phorescence of some organic bodies is due to this cause. Sul- 

 phuretted hydrogen is found in numerous putrefactions, and is 

 produced, probably, in a similar manner. It exists in sewer gas, 

 and can be recognised by the blackening of paper, which has 

 been moistened with a solution of some soluble lead or silver 

 salt. The amount of sulphuretted hydrogen present can be 

 estimated by the intensity of the colour produced, as compared 

 with standard colours. Minute quantities, such as that present 

 in a single human hair, are recognised by the violet colour pro- 

 duced with it by a solution of sodium nitrorprusside in strongly 

 alkaline solution. Marsh gas and defiant gas are two hydro- 

 carbons which are also produced in decay, the former existing 

 in the bubbles of gas evolved from the bottom of stagnant ponds. 

 Ammonia, as already mentioned, is a frequent product of decay, 

 and from its solubility in water, affords an indication of former 

 putrefaction. The compound ammonias, ethylamine, propylamine, 

 and butylamine — are formed in the decay of such substances as 

 flour, herring roe, etc. Bones, when distilled, similarly yield 

 several of these compound ammonias. Putrefying flour yields 

 also trimethylamine and amylamine, which are bodies belonging 

 to the same group of substances. Nessler solution serves to 

 identify the presence of ammonia, if formed in matter undergoing 

 decay. The compound ammonias can be decomposed into 

 ammonia by boiling with potash, and so recognised by the same 

 test. Ammonia, on oxidation, yields nitrogen, nitrites, or 

 nitrates. In nature, when the oxidation proceeds slowly, nitrites 

 and nitrates are the products of the change ; nitre beds, which 

 exist in large quantities in sub-tropical climates, are produced 

 in this way, by the nitrification of ammonia in the presence of 

 bases such as potash and lime. 



THE INSTITUTION OF CIVIL ENGINEERS. 



THE MANUFACTURE OF SALT NEAR MIDDLESBROUGH. 



AT the ordinary meeting on Tuesday, the 17th of May, the 

 paper read was " On the Manufacture of Salt near Middles- 

 brough," by Sir Lowthian Bell, Bart, F.R.S., M.Inst.C.E. The 

 geology of the Middlesbrough salt region was first referred to, 

 and it was stated that the development of the salt industry in 

 that district was the result of accident. . In 1859, Messrs. 

 Bolckow and Vaughan sank a deep well at Middlesbrough, in 

 the hope of obtaining water for steam and other purposes in 

 connection with their ironworks in that town, although they had 

 previously been informed of the probably unsuitable character of 

 the water if found. The bore-hole was put down to a depth of 

 1,200 feet, when a bed of salt rock was struck which proved to 

 have a thickness of about 100 feet. At that time one-eighth of 

 the total salt production of Cheshire was being brought to the 

 Tyne for the Chemical Works on that river; hence the discovery 

 of salt instead of water was regarded by some as the reverse of 

 a disappointment. The mode of reaching the salt rock by an 

 ordinary shaft, however, failed, from the influx of water being 

 too great, and nothing more was heard of Middlesbrough salt 

 until a dozen years later, when Messrs. Bell Brothers, of Port 

 Clarence, decided to try the practicability of raising the salt by 

 a method detailed in the paper. A site was selected I,3i4yards 

 distant from the well of Messrs. Bolckow and Vaughan, and the 

 Diamond Rock-Boring Company was entrusted with the work of 

 putting down the hole. This occupied nearly two years, when 

 the salt, 65 feet in thickness, was reached at a depth of 1,127 

 feet. Other reasons induced the owners of the Clarence Iron- 

 works to continue the bore-hole for 150 feet below the bed of 

 salt ; a depth of 1,342 feet from the surface was then reached. 

 During the process of boring, considerable quantities of inflam- 

 mable gas were met with, which, on the application of flame, 

 took fire at the surface of the water in the bore-hole. The origin 

 of this gas, in connection with the coal measures underlying the 

 magnesian limestone, will probably hereafter be investigated. 

 For raising the salt recourse was had to the method of solution, 

 the principle being that k column of descending water should 

 raise the brine nearly as far as the differences of specific gravity 

 between the two liquids permitted— in the present case about 

 997 feet. In other words, a column of fresh water of 1,200 feet 

 brought the brine to within 203 feet of the surface, and it was 

 then pumped up. 



THE GEOLOGICAL SOCIETY. 



A MEETING of this Society was held on May 11, Prof. J. W. 

 Judd, F.R.S., president, in the chair. The following com- 

 munications were read : — 



(i) " Further Observations on //)'/(vW(;/C(ifo« Gordom." By 

 Prof. T. H. Huxley, LL.D., F.R.S., F.G.S. The author briefly 

 noticed the circumstances under which he first described the 

 occurrence of Lacertilian and Crocodilian fossils in the Elgin 

 Sandstones, and the confirmation which his views as 

 to the Mesozoic age of these remains had received from the 

 discovery of Hypcrodapcdon in English Triassic rocks and in 

 India. The original type o{ Ilyperodapcdoti Gordoni iiova Elgin 

 was, however, in bad condition, and the receipt at the British 

 Museum of a second much better preserved skeleton, found in 

 the Lossiemouth quarries of the same neighbourhood, had enabled 

 him to add considerably to the known cliaracters of the genus, 

 and to compare it more thorouglily both with the recent Spheno- 

 doii (or Haitcria) of New Zealand and with the Triassic Rhyn- 

 chosaunis articcps, several specimens of which are in the British 

 Museum palceontological collection. 



(2.) " On the Rocks of the Essex Drift." By Rev. A. W. Rowe, 

 M.A., F.G.S. The rocks of the drift in Essex are of such great 

 variety that it is difficult both to get a really representative 

 collection and to classify them when they have been collected. 

 About two hundred specimens have been taken, and sections 

 have been made of one hundred and fifty of these. There is a 

 remarkable absence of granite of any kind, and only two speci- 

 mens of syenite have been found. Ouartz-porphyrites and 

 quartz-tourmaline rocks are fairly abundant, felsites are rarely 

 met with, but felspar porphyrites are very abundant ; trachytes 

 also are found, but there is some reason for suspecting that 

 these do not really belong to the drift, but have been imported 

 in very early times. The most abundant of the igneous rocks 

 are the dolerites ; but all the coarser dolerites and those of a 



