1844.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



II 



GLASS, WATER AND GAS MAINS. 



(Translated for the Civil Engineer and Archilect's Journal from the Bulletin 

 du Miisee de I' Industrie.) 



The subject of glass mains is attracting some attention in France. Earth- 

 enware pipes have also been used on a small scale ; they must not, however, 

 be subjected to a pressure of two or three atmospheres, as the joints being 

 difficult to lute, give way, whatever cement may be used. For luting, some 

 gas companies have used Roman cement, but the gas escapes by impercep- 

 tible fissures at the joints, and they have been found so objectionable, on 

 account of the frequent escapes and disturbance of the pavements for repairs, 

 that the local authorities have objected to the use of earthenware mains in 

 such situations. The glass mains, manufactured by Messrs. Bergeron of 

 Rive de Gier, are luted with bitumen, and may be screwed together. The 

 weiglit is about a third of that of cast iron, and the cost laid down about 

 7s. Crf. per yard run for a 4Hn. bore. The process at present will not pro- 

 duce pipes of more than 8 in. bore. Of course, in England, with the low 

 price of cast iron and the duty on glass, glass pipes are out of the question 

 on economical grounds. 



AGRICULTURAL CHEMISTRY. 



Report of two Lectures delivered by Professor Brande, F.R.S., to the members 

 of the Royal Agricultural .Association of England, at the Royal Institution, 

 Albemarle-sireet, on Wednesday and Thursday the Gth and 7th December, 184.3. 

 (Specially reported for this Journal.) 



Lecture I. 



In compliance with the request of your noble President, I have the liomuir 

 to deliver to you two lectures upon subjects connected with agricultural Iiis- 

 tory. The subjects which I hnve chosen are those of lime and clay ; ami I 

 have fi.^ed upon these for reasons which I shall presently describe to )'ou 

 more at length. I think you will agree with me that under existing circum- 

 stances, the union of practice witli theory in the subject that is engaging our 

 attention is more than ever desirable; and that the important bearings of 

 chemical science upon agriculture become daily more and more evident. 

 Why cAcm/ra; science ? Because e.vpetience teaches us that that sort of su- 

 perficial knowledge wh'.cli may enable a man to make rough analyses uf 

 soils, to discover theirleading constituents, and to ascertain their relative pro- 

 portions, is far from being sufficient to satisfy the demands which the scien- 

 tific agriculturist thinks it right to make upon the practical chemist; much 

 more than this must be expected from the chemist — information, indeed, 

 wliich can only be furnished by the experienced analyst. 



It was long ago shown by Sir Humphrey Davy, and the celebrated Liebig 

 has proved more recently, that the fertility of a soil, as relates to the produc- 

 tion of particular crops, may depend upon the presence, or absence, of very 

 minute and almost imperceptible portions of inorganic substances — alkalis, 

 for instance, and the sails of metals — substances which, a few years av.u, 

 were either entirely overlooked, or thought nut worth looking after or men- 

 tioning it discovered; the necessity, for example, of sulphate of lime to 

 clovers, silica to grasses, phosphorus to wheat, and so on, was quite disre- 

 garded. But now these matters are beginning to attract notice, and to open 

 up new fields of chemical inquiry, wliich can only be successftdly cultivated 

 by the joint labour of the farmer and the chemist ; hence every one inter- 

 ested in the welfare of chemistry — and what rightly constituted person is not 

 so ? — must see with unlimited satisfaction, and with a happy anticipation of 

 the future, the good feeling that is beginning to dawn between practice and 

 theory — between the agriculturist and the chemist. We are beginning to 

 " scent the morning air," as it were, of a better order of things, and it is 

 with great satisfaction that I myself see, that you, gentlemen, impressed 

 with the importance of this union, have associated an eminent chemist w iih 

 your body, and that many valuable papers are beginning to appear in your 

 useful Journal. 



.Soils are made up of organic and inorganic constituents. AV'e are now to 

 confine ourselves to the latter, and these we class under two heads ; first, 

 those which constitute the bulk of the soil, and on the mechanical texture 

 of which the growing crops depend, such as clay, sand, and lime ; and se- 

 condly, those particular substances involving the fitness of a soil for parti- 

 cular crops, such as sulphate and phosphate of lime, soda, ammonia, mag- 

 nesia, &c. 



Lime is an article no doubt of great importance to agriculture, and some of 

 some of its salts perform such important, though often obscure, functions, that 

 I propose first to consider it, and then to call your attention to sihcious and 

 aluminous substances as existing in soils, which constitute clays. 



Firs!, I may ask, what is lime? The chemist will tell you it la a com- 

 pound of a metal and oxygen, being w hat he calls a metallic oxide, consisting 

 of 20 parts by weight of calcium and 8 of oxygen. I cannot show you this 



metal, calcium ; but I can show you the counterpart of it. It has hitherto 

 b.'en obtained in very minute ipiantities. It is one of those extraordinary 

 metals discovered by Sir Humphrey Davy which is most difficult to procure, 

 in consequence of its high affinity for oxygen. The moment it is olitained 

 and exposed to the air, it passes into lime. At the instant when deprived of 

 oxygen, we see it as a brilliant metal, but the moment the air is admitted it 

 passes into lime. 



I will now show you, as its counterpart, the metal potassium, which is a 

 white brilliant metal, resembling silver or lead in appearance, and distin- 

 guished by its strong affinity for oxygen, and by burning when put into 

 water. If it is thrown into water, it will take fire, dissolve, and produce a 

 solution of metallic oxide — so also with the metal calcium, the base of lime. 

 I'here is another ch.iracter belonging to this solution, which likew ise belongs 

 to i:me, and that is, that it is what chemists call an alkali ; and the test of 

 an alkali is that it reddens blue litmus paper, and browns paper tinged with 

 yellow. 



Lime does not exist in a native state— small quantities have been found 

 in some of the lakes of Tuscany, but it may be said not generally to exist in 

 a native state. What then arc its sources ? The best known is carbonate of 

 lime, which is very abundant, and which recommends itself especially as a 

 source of lime, in consequence of the facility with which it admits of decom- 

 position. Carbonic aciil has a weak affinity for other bodies, and can there- 

 fore be easily got rid of. But I must stop here, to tell you that carbonic 

 acid is a substance which combines with lime, and exists with lime in all its 

 natural spars. It is composed of charcoal and oxygen. Lime, as was just 

 told you, is composed of a metal and oxygen, and on the one hand we have 

 a compouml of oxygen and a metal producing an alkali, and on the other 

 hand carbon and oxygen producing carbonic acid. (The learned Profi-ssor 

 then proceeded to illustrate by experiment the formation of carbonic acid 

 from carbon and oxygen, and for this purpose he inserted a piece of burning 

 charcoal into a glass jar containing oxygen gas;) he then observed, 

 there is charcoal introduced into oxygen gas burning vehemently — doing, 

 in fact, what it does in the commim air, where it burns by virtue of the oxy- 

 gen which the air contains. If the charcoal be allowed to continue burning 

 as long as it will, we shall find that a large quantity of it has disappeared ; the 

 oxygen has lost all its original qualities, has combined with the carton, and 

 become carbonic acid, and that acid combining witii lime, pro<iuces,as before 

 said, carbonate of lime. We here employed first, combustible metal, then 

 charcoal, and then oxygen, and these are the ultimate elements of carbonate 

 ol lime ; the proximate elements are carbonic acid and lime. 



Now you must not forget that all we do here, and in fact all the bases of 

 chemical combination, are bound down l)y the strictest laws of weight and 

 measure; and though charcoal is burnt in oxygen without any reference to 

 weight, it can only combine in certain weights. So also when the metal of 

 lime is thrown into water, it burns, but requires a particular quantity to be 

 combined with a particular quantity of oxygen to produce lime. Six parts 

 of carbon added to \H parts of oxygen produce 22 parts of carbonic acid ; 

 20 parts of calcium added to 8 parts of oxygen produce 28 parts of lime ; 

 and thus 28 parts of lime added to '22 parts of carboni.c acid will produce 

 50 parts of carbonate of lime. 



Carbonate of lime constitutes in various forms mountains and hills and 

 strata, covering immense distances ; and it is common to speak of it as pri- 

 many, secondary, and lerti.ry limestone, meaning that it occurs in those 

 series of rocks considered generally under those terms, Hdiicli may be ex- 

 plained as signifying the older, intermediate, and newer strata of our globe. 

 There are a number of specimens of limestone upon the table, but I will 

 only select a few to show you the distinct char.icters of each. 



Tlie primary or primative limestone, illustrated in marble of different 

 kinds, more especially in the crystallised white marble of Carrara and the 

 Al|is, in statuary marble, and other varieties of limestone, has no organic re- 

 mains, because it has been subjected to great fires and beat, in which it has 

 heen fused, and thus lost all traces of organic remains. In the secondary 

 limestone we discover more or less of organic remains, and we may trace in 

 some of them the aggregates of corals and other bodies. The Derbyshire 

 spar is a specimen of this limestone. We now come to lime of the newest 

 or tertiary strata, and here we can trace the remains forming at the present 

 time. Shells are ground up and cemented in various ways, producing a 

 variety of limestones. 



In regard to chalk, it is right I should remind you that there are strata 

 distinguished as chalk with, and clialk without, flints. One particular pro- 

 lierty of the latter is that mortar made of it hardens under water, and it is 

 hence valuable as a hydraulic lime. 



There are a number of varieties of carbonate of lime producing calcareous 

 spars. Coral and shells, for instance, are made up of carbonate of lime. And 

 I will now remind you, that to whatever source you gu for carbonate of lime. 

 It is composed of carbonic acid and lime. You may easily recognize calca- 

 reoLis stone by the lest of its effervescing in acid ; and if you take any kind 

 of limestone, and pour upon it a weak acid, effervescence ensues arising 

 from the escape of carbonic acid, and this may be taken as a test of the pre- 



