It is some satisfaction to know that these houses have lately awakened the apathy of some of the public bodies, and that more than one scheme is being put forward with a view of erecting proper industrial dwellings. The Municipal Council is negotiating with the Credit Foncier for the erection of a certain number of cheap houses, which, for the space of twenty years, will be exempt from all taxes, such as octroi, highway, door and window tax, etc. There are also one or two semi-private companies, which are occupying themselves with the question, and it is to be hoped that the rumors of the pestilence in Egypt may hasten the much-needed reform. * * * * * There can be no doubt, says the _Engineer_, that the inventor who could supply in a really portable form a machine or apparatus that could give out two or three horse power for a day would reap an enormous fortune. Up to the present time, however, nothing of the kind has been placed in the market. Gas is laid on to most houses now, and gas engines are plenty enough, yet they do not meet the want which a storage battery may be made yet perhaps to supply. * * * * * RECENT EXPERIMENTS AFFECTING THE RECEIVED THEORY OF MUSIC. To prove the incorrectness of Helmholtz's statement that beats do not colesce into musical sounds, but that the ear will distinguish them as a rumbling noise, even when their number rises as high as 132 vibrations per second, Rudolph Koenig has constructed a series of tuning forks, recently presented by President Morton to the Stevens Institute of Technology. The following table exhibits the number of vibrations per second of these forks, the ratios of their vibrations when two are sounded together, the number of beats produced, and the resultant sound: Vibrations per second. Ratio. Beats. Sounds.