Notices respecting New Books. 311 



more, however, than the evidence of the mere bodily senses 

 may be required, to appreciate the truths of nature, as it is a 

 notorious fact that the most important truths generally lie 

 below the surface. It should be noted that these media would 

 not be efficient as working agents unless they were concealed ; 

 for concealment (as observed) is the necessary condition to the 

 enclosure of a store of motion to a high intensity. Possibly 

 the absence of realization of this fact, and perhaps that pre- 

 judice which besets every new path, may in some degree 

 account for what must otherwise appear an extraordinary 

 indifference and absence of inquiry in a subject of great me- 

 chanical interest and involving possibly issues of the highest 

 importance and practical utility. When this, like every other 

 illogical prejudice to change, comes to be broken down by the 

 light of reason and reflection, there may be just ground for 

 surprise at the previous delay, and at the shallow and unsub- 

 stantial character of the theories which so long supplanted 

 rational conceptions of the processes of nature. 

 London, Marcli 13, 1878. 



XLIII. Notices respecting New Books. 

 Des Paratonnerres a Pointes a Conducteurs et a Raccordements Ter- 

 restres Multiples. Description detaillee des Paratonnerres etablis sur 

 T Hotel de Ville de Bruxelles en 1865. Expose des motifs des dis- 

 positions adoptees par Melsens, Membre de V Academic Royale des 

 Sciences de Belgique. Bruxelles : Hayez. 1877. 

 rPHE work, of which the title is given above, possesses an interest 

 -*- not only to the electrician and man of science, but to the 

 architect and antiquary; and Professor Melsens, already so favour- 

 ably known to the world of science, has done further good service 

 in applying sound scientific principles to the preservation of those 

 grand monuments of mediaeval architecture of which his country is 

 so justly proud. The origin of the work which we now notice was 

 in the circumstance that, in a thunder-storm in 1863, one corner 

 tower of the Hotel de Ville at Bruxelles was struck by lightning, 

 and that portion of the building seriously injured, whilst the very 

 much higher central tower and spire were not touched. The muni- 

 cipal authorities of Bruxelles at once proceeded to consider the steps 

 to be taken to preserve the building from any future like injury, 

 and requested the assistance of the Academy of Sciences, which 

 appointed a committee. Opinions were very much divided, and no 

 practical conclusion was arrived at; so the Municipal Council 

 very sensibly passed over the Committee and placed the whole 

 matter in the hands of Professor Melsens, who had formed definite 

 ideas on the subject, and was prepared to take the responsibility of 

 carrying them out. The great difference of opinion among scientific 

 men was as to the comparative advantages of concentrating the 

 means of defence in one or a very few lightning-conductors ex- 

 tended to a great height, overtopping the most elevated portions of 



