PROTECTION FROM LIGHTNING. 



49 



the lightning. This state of the compasses continued throughout 

 the remainder of the voyage." 



In 180S, a Genoese ship was wrecked near Algiers, while the 

 captain and crew, deceived by the false indications which light- 

 ning had induced in the compasses, thought they were sailing 

 directly from the dangers which proved the destruction of 



their vessel. The effects of lightning upon the needles of sea 

 compasses haveo/fen led to like serious consequences. Lightning 

 may not only directly influence compass needles, but indirectly by 

 magnetizing pieces of hard iron and steel throughout a vessel, 

 which at once become agents in the deflection of the needles. 

 Such deflections are sources of peril, especially as it is not an 

 eas3 T matter for the navigator on the high seas, even when he is 

 aware that an error of the compass exists from such a cause, 

 to determine its value. His condition is still more perilous when 

 the steel pieces of his chronometers are also magnetized by light- 

 ning. Dangerous errors are then likely to occur in the compu- 

 tation of geographical longitude. The chronometers of the " New 

 York," a packet which was twice struck by lightning while at 

 sea on the 19th of April, 1S27, were found on arrival at Liverpool 

 to be 33 minutes 58 seconds in advance of what they would have 

 been ;< but for the stroke by lightning of the vessel. Adequate 

 means should evidently be provided on every vessel for conveying 

 away harmlessly the electric discharge. 



Without considering at present, more in detail, the properties 

 and peculiar characteristics of lightning, let us come directly to 

 the question : Is the extent of danger from this source so great 

 as to give importance to means of averting it ? The only answer 

 really needed to this inquiry is a reference to our daily papers 

 during the warm season. How many accounts do we see of barns 

 recently filled with newly made hay struck by lightning, and of 

 them aud their contents destroyed ! How often we read of per- 

 sons killed, buildings fired, and other injuries done by this agent. 

 Extended statistics showing the amount of damage by lightning 

 through a series of years are not readily obtained. Our con- 

 ception of the extent of damage may, however, be aided by the 

 following facts : 



From the month of June to the 28th of August, 179*7, Volney 

 counted up in the newspapers of the United States, eighty-four 

 serious accidents, and seventeen deaths by lightning. It is more 

 than probable he did not obtain an account of all. 

 4 



