454 Notices respecting New Books. 
which the original mode of practice exhibited. Mr. A., sensible 
of this, felt, as he informs us, that he should have been “ guilty 
of an injustice to the constant demand which still exists for his 
former Treatise,’ had he not made it his duty to suit it to the 
changes which have taken place; and in execution of this de- 
sign, | he has now presented the public with what is in fact quite 
a new work, superseding altogether the former publication, but 
superseding it, we must readily allow, from circumstances of ne- 
cessity, and with an undoubted view to the public good. 
The object which Mr. Accum seems already to have pursued 
in the present work has been, to make it a compendium of all the 
best information which the practice of the art down to the present 
moment has been able to afford ; and we must do him the justice 
to state it as our opinion that he has fulfilled his object with 
equal amplitude and exactness. It includes not only the result 
of his own experience in this department, which appears to have 
been extensive, but a great number of valuable data with which 
he has been favoured by other gentlemen practically versant in 
the art; and we are well satisfied the ingenious author will not - 
be disappoiiited in the hope he expresses of its proving a work 
-of truly practical utility. 
The following are the contents of the work : Part I. General na- 
ture and advantages of the art of procuring light by means of car- 
oS 
buretted hydrogen or coal-gas.—II. Outline of the new art of pro- 
curing light by means of coal-gas, and theory of the production of 
gas- lights. —III. Classification of pit-coal and maximum quantity 
of gas obtainable from different kinds of coal.—IV. Form and di- 
mensions of. the retorts originally employed for manufacturing 
coal-gas ; application of heat; the plan originally adopted; re- 
port on a course of operations made with sets of 66, of 30, of 
116, and of 64 retorts worked on the flue plan; oven plan lately 
adopted ; description of the retort oven.—V. and VI, Account 
of experiments pursued on a large scale in order to ascertain the 
most profitable mode of employing the retorts; differences of 
opinion wich have existed among practical men with respect to 
the degree of temperature fittest to be applied, and the number 
of hours at a time during which the retorts may most advan- 
tageously be kept in action, with the particular results which the 
experiments instituted into these points have afforded ; and va- 
rious other data calculated to enable the reader to adopt that 
mode of operation which under every circumstance of locality 
will be found most advantageous.—VII. Detailed description of 
_ the horizontal rotary retorts, the application of which has led to 
a more ceconomical, expeditious, and easy method of manufac- 
turing coal-gas than heretofore practised ; advantages which these 
retorts present 5 particular results they- afford, and method of ap- 
plying 
