HARDWICKE'S SCIENCE-GOSSIP. 



195 



should be nakedly exposed, and the more they stink 

 the better. What we require is that all the sewage 

 of all our towns, all our villages, all our farm-houses, 

 and all other human habitations shall be deodorised 

 and restored to the land. This certainly can be done, 

 and would be done if the doing of it were compulsory, 

 and therefore the sooner we are compelled to do it, 

 by the urgency of intolerable stench and wholesale 

 pestilence, the better. 



In a letter from " Our Correspondent," dated 

 "Marseilles, Friday, August i," and printed in The 

 Times of August 2, is the following: "The muni- 

 cipality is washing the lower parts of the houses, the 

 drain openings, and the kerbstones with sulphate of 

 copper. The red colour of our streets may be 

 imagined." This is curious, seeing that sulphate of 

 copper is not red, l)ut very deeply green or nearly 

 blue. It is quite true that the red colour " may be 

 imagined," but certainly it does not exist as a con- 

 sequence of using sulphate of copper. Sulphate of 

 iron is sometimes called "green copperas," and this, 

 if applied to limestone, would be decomposed into 

 sulphate of lime and iron-carbonate, which carbonate 

 by exposure to the air would presently become red 

 sesquioxide of iron. I suspect that " O. C." has 

 been a victim of the word "copperas," though I 

 am not aware of its use in France. Sulphate of 

 copper applied to limestone would produce a 

 malachite-green stain. 



The old subject of the influence of gun-firing on 

 rainfall has been revived at the Antipodes, in a paper 

 read at the Royal Society of New South Wales by 

 Edwin Lowe, who advocates the practical use of 

 explosions for the purpose of effecting precipitation. 

 The subject is one of such vital importance in 

 Australia, where so many millions of sheep have been 

 lost during the last five years for lack of rain, that 

 something more than mere speculative paper-reading 

 is demanded there. Experiments on a scale of 

 sufficient magnitude to settle the question one way 

 or the other should be made ; and it is idle, feeble, 

 and unjust to leave such researches to private enter- 

 prise. The value of the sheep lost in a single month 

 would, if judiciously expended, settle the question for 

 ever. 



The 'climate of Australia is specially suitable for 

 the experiment. The uniform sweep of the upper 

 currents over its vast area, and its normal uniformity 

 of climate, permit the testing of the vexed question 

 by promoting a' local disturbance and observing the 

 local effect. 



During the recent sultry weather, I have made 

 some observations that strikingly illustrate the folly 

 of one of our customs, which is blindly followed by 

 people who ought to know better, and would know 

 better, if at all addicted to thinking about common 

 things. I refer to the practice of opening doors and 

 windows in hot weather for the purpose of keeping the 

 house cooL Seeing that the heat of a summer day comes 



from without, the absurdity of such a practice is evident 

 enough. I placed thermometers in two rooms ; one 

 a large room extending from front to back of the 

 house, the other just half the size, with windows only 

 on one side, facing north-west. Both windows of 

 the larger room were thrown open to secure the 

 " thorough draught " so much esteemed by the 

 majority in hot weather. The window and door of 

 the smaller room were closed. I found a difference 

 varying from five to nine degrees on different days, 

 between two and three P.M. The superior coolness 

 of the closed room was evident at once, on passing 

 from the open room ; it appeared even greater than 

 the thermometer indicated. To keep a house as cool 

 as possible in summer time, all '^doors and windows 

 should be closed from ten A.M. to five P.M., and the 

 blinds as well as the windows closed on the sunny 

 side.. The more open the better during . the early 

 morning, the evening, and night. Of course, in very 

 small houses, where the inmates are crowded, the 

 hot air from outside must be endured for oxygen 

 sake. 



School holidays should be arranged on meteoro- 

 logical principles. Having determined the number 

 of weeks of the summer vacation, tables of average 

 day temperature should be consulted, and the hottest 

 five, six, or other number of weeks should be chosen. 

 A crowded school-room caimot be kept cool by 

 excluding the outer air. 



Various devices have been suggested for the diffu- 

 sion of popular scientific knowledge, the latest being 

 one that has come about by a process of natural 

 selection. Professor Milne, of Tokio, in Japan, has 

 constructed a pair of pendulum seismographs, instru- 

 ments for the automatic delineation and registration 

 of the earthquake disturbances so frequent in that 

 country. He wrote describing them as "conical 

 pendulums," each consisting " of a heavy mass sus- 

 pended by a string." The printer of a local paper 

 improved the original by desci'ibing them as ' ' comical 

 pendulums," consisting of "a heavy man suspended 

 at the end of a string." This rendered the apparatus 

 extremely interesting to the general reader, and led to 

 many inquiries that have diffused extensive knowledge 

 of the subject, so much so, that in the interest of 

 popular education, the typographical errors have not 

 been corrected. 



It appears from the testimony of several corres- 

 pondents in " Health," that the crowing and clucking 

 of a neighbour's fowls is a serious nuisance. The 

 complaints of the aforesaid correspondents are very 

 loud and bitter. 



I have heard much of this before, and have deduced 

 a very curious psychological law, by collating the 

 facts connected therewith. This law is that people 

 generally are kept awake and seriously annoyed by 

 their neighbours' fowls, but not by their own. This 

 law is so universal that if A., who lives in a semi- 

 detached villa and keeps fowls which have destroyed 



