24 IMPROVING NATURAL KNOWLEDGE 



severe fires sometimes occur and inflict great damage, 

 the loss is very generally compensated by societies, the 

 operations of which have been rendered possible only 

 by the progress of natural knowledge in the direction 

 of mathematics, and the accumulation of wealth in vir- 

 tue of other natural knowledge. 



But the plague? My Lord Brouncker's observation 

 would not, I fear, lead him to think that Englishmen of 

 the nineteenth century are purer in life, or more fervent 

 in religious faith, than the generation which could pro- 

 duce a Boyle, 15 an Evelyn, 16 and a Milton. He might 

 find the mud of society at the bottom, instead of at the 

 top, but I fear that the sum total would be as deserving 

 of swift judgment as at the time of the Restoration. And 

 it would be our duty to explain once more, and this time 

 not without shame, that we have no reason to believe 

 that it is the improvement of our faith, nor that of our 

 morals, which keeps the plague from our city ; but, again, 

 that it is the improvement of our natural knowledge. 



We have learned that pestilences will only take up their 

 abode among those who have prepared unswept and un- 

 garnished residences for them. Their cities must have 

 narrow, unwatered streets, foul with accumulated gar- 

 bage. Their houses must be ill-drained, ill-lighted, ill- 

 ventilated. Their subjects must be ill- washed, ill- fed, 



15 Robert Boyle (1627-1691) is best known as a physicist and 

 the discoverer of Boyle's law of the elasticity of gases. Huxley re- 

 fers to him here, however, as the student and propagator of 

 religion. He established by his will the "Boyle lectures" for the 

 defense of Christianity against unbelievers. 



16 John Evelyn (1620-1706), the diarist, is described by Leslie 

 Stephen as "the typical instance of the accomplished and pub- 

 lic-spirited country gentleman of the Restoration, a pious and 

 devoted member of the Church of England and a staunch loy- 

 alist in spite of his grave disapproval of the members of the 

 court." Both Boyle and Evelyn were members of the Royal 

 Society. 



