504 Notices of Books. [Oétober, 
boiler, with pipes from 1 to 4 inches diameter, and a supply- 
cistern; coils of tubing, about 2 inches diameter, are placed 
where warmth is required, smaller pipes being used to convey 
the water to the coils. The size and length of the apparatus 
cause it to be rather unsightly, and the heat cannot be so equally 
distributed, although it is preferable in places removed from 
large towns, from the fact that an ordinary mechanic can attend 
to any repairs that may be necessary. The high-pressure 
system is better adapted to large houses, where several lobbies 
require warming. That described in the foregoing work is an 
admirable system, peculiarly adaptable to our climate, where the 
direct admission of cold air to our rooms is endumeole only a 
few months in the year with due regard to health; and we 
commend the work to our readers as well deserving their con- 
sideration. 
New Formulas for the Loads and Deflections of Solid Beams 
and Girders. By Wituitam Donatpson, M.A., A.I.C.E. ; 
Author of ‘‘ Switches and Crossings,” and a “Treatise on 
Oblique Arches.” London and New York: E. and F.N. 
Spon. 1872. 
Ir has been well said, by an American writer, that ‘* The least 
deviation from the assumed standard (of pronunciation) converts 
the listener into a critic.” And the same may be said of spelling. 
In the present work we have formulas, the assumed standard 
being formule. Now Mr. Donaldson may be more studious of 
the formation of the plural in the English language than is per- 
haps agreeable; for certainly this deviation from the assumed 
standard not only causes the thoughtful reader to pause, but its 
reiteration interferes with the grasping of the sense, and is most 
damaging to the ready perception of the course of reasoning. 
Where argument has to be so closely followed as in a mathe- 
matical work, every consideration should be given that there 
occurs nothing to distract the attention. This variation we 
advise Mr. Donaldson to alter in future editions, at least in the 
body of his work. We say advisedly in future editions, for the 
practical worth of the work will be at once recognised by the 
engineer. The formule are clearly deduced and plainly stated, 
while the illustration of the applications is of a high order. 
Contributions to Molecular Physics in the Domain of Radiant 
Heat. A Series of Memoirs published in the ‘“ Philoso- 
phical Transactions” and ‘‘ Philosophical Magazine,” with 
Additions. By Joun Tynpatt, LL.D., F.R.S., Professor of 
Natural Philosophy in the Royal Institution. London: 
Longmans and Co. 1872. 
Screntiric readers will recognise these memoirs which Dr. 
Tyndall has now produced in a book-form; to the general public 
