18«.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



271 



deficient information furnished to us in our original inquiries. 

 AVe have constantly endeavoured to rectify any omissions of this 

 kind, when pointed out, and the investigation heing still in pro- 

 gress, the opportunities for so doing will receive every attention. 

 It is in accordance with this view that we have included in this 

 Report various coals from the South Wales coal-lield m hich ha\e 

 been sent to us since the publication of the first Report. The 

 examination has been made, as far as possible, by districts, and, in 

 accordance with this arrangement, the Lancashire and Newcastle 

 coal-fields have principally engaged attention in the present 

 Report. 



The peculiar quality of the coals employed in the experiments is 

 ascertained by chemical analysis. The character of the economic 

 and chemical experiments differ essentially in one respect — viz., 

 that while in the former many hundred weights are employed in 

 the experiments, in the latter only a few grains are required. It 

 is, therefore, essentially necessary to take precautions that these 

 few grains represent the average state of the coal. In order to 

 ensure this result, a large quantity of the coal is reduced to powder 

 and is well mixed, by passing through sieves of various sizes. The 

 larger fragments remaining on the wider meshes are reduced to 

 powder, so as to enable them to pass through the finer sieves, and 

 be completely mingled with the remainder. The quantity of coal 

 to be examined is taken from this carefully a\''eraged sample. It 

 is found by experiment, that perfectly accordant results are ob- 

 tained, when small quantities are operated upon, and that imper- 

 fect combustion, and therefore discordant numbers, always attend 

 the use of large quantities. These analytical results are placed in 

 Table II. In that table also will be found some valuable analyses 

 of coals from foreign stations, which have from time to time been 

 sent to us from the Admiralty. 



Table IV. — Showing the Expansion of Water in the Boiler at different 

 Temperatures. 



Another more simple means of identification, which it is conve- 

 nient to record, is obtained by estimating what has been termed 

 the calorific value of the eoal. This depends upon the circum- 

 stance, tliat within certain limits of error, the calorific value of a 

 coal may be expi-essed by the quantity of oxygen required to con- 

 sume it. This amount is experimentally determined by the quan- 

 tity of lead which the coal reduces when heated with an excess of 

 litharge, that oxide yielding the amount of oxygen necessary for 

 the combustion of the coal. Properly considered, all combustible 

 matter should be viewed as adding its increment to the calorific 

 result, and as suc^h should be allowed its value; but as the amount 

 of sulphur in coals, although increasing the calorific unit, is objec- 

 tionable in many respects, it maybe considered advisable to correct 

 the table for the quantity of lead reduced by it. This correction 

 is not, but may, be very simply made for Table III. by the follow- 



ing formula 



L-(f X 0-77) 



in which L is the quantity of grains of 



lead reduced by 5 grains of coal, s, per centage of sulphur as shown 

 in column E. of Table II. 



Tlie correction has not been made, as it is thought better to give 

 the actual result of experiment, and because tlie correction is 

 within the errors of repeated experiments. In most cases, the 

 error arising from iron pyrites is within 0-1 to 0-19 per cent, of t!ie 

 total lead found, and as this quantity is less tlian tlie difference 

 between three successive experiments, it obviously falls within tlie 

 limits of error, and may be safely rejected, so far as the practical 

 result is concerned. 



It may be desirable to state that the next Report will include 

 the remainder of those coals which it is thouglit exjiedient to 

 examine. The investigation continues to be conducted in the 

 same manner as formerly, our own superintendence being freely 



given as heretofore, and the actual practical experiments being 

 confided to Mr. J. Arthur Phillips. Mr. How conducted the che- 

 mical analyses, until liis removal to Edinburgh, after which they 

 were undertaken by Air. T. T. Philipps. 



Table V. 



Table VI. — Correction for Erpar,sion and Contraction of Water in the 

 Tanks, taking 70° as the Normal Temperature. 



In acknowledging the kind and liberal support which has been 

 extended to us by those desii-ous of promoting this inquiry, we 

 would wish more especially to call attention to the disinterested 

 and important aid afforded by Mr. Samuel Hocking, to whose 

 gi-eat knowledge of Cornish boilers we are indebted for much 

 valuable information, and for having personally superintended the 

 setting of the boiler employed in these researches. 



REViEiars. 



A Report on Indian River Navigation ; addressed to the Committee of 

 Gentlemen formed for the estal/linhment of Improved Steam Naviga- 

 tion upon the Rivers of India. By John Boubne, C.E. London - 

 Allen. 1849. 



Mr. Bourne went out to India with Mr. Macdonald Stephenson 

 as one of the engineers of the East Indian Railway, and had thus 

 the opportunity of examining the Lower Ganges. This has led 

 him to devote his attention to the subject of Indian river naviga- 

 tion, the drawing up of a plan for that purpose, and the publica- 

 tion of the present pamphlet. Certainly the subject is one of very 

 great importance, and which has been very much neglected, as we 

 have heretofore shown; and it speaks but ill for the Indian govern- 

 ment that steam navigation should be at its present low ebb. For 

 the non-extension of railways they have an excuse, that the pre- 

 liminary trials are not yet made; but steamboats have long been 

 tried, and have been found successful. As yet, there are only 

 steamboats on the Ganges, though it is known they will run oil 

 the Indus, and on the Assam river or Buri-ampooter. 



The true answer to any objections is, that no proper facilities 

 are given for private enterprise in India. It is worse off than 

 here; and instead of the steamboat being used in India, as in 



