Progress of Invention. 391 



before expressed of Mr. Page's labours, and add that bis volume is 

 well illustrated, and so low in price as to be within the reach of 

 students of very small means — a fact which we consider important. 

 Mr. Page's larger work made its first appearance in 1856, and the 

 demand for a fourth edition, so soon as 1867, shows the well- 

 deserved repute in which it is held. The present edition appears 

 to notice all recent facts of importance. It is well printed and well 

 illustrated. 



PROGRESS OF INVENTION. 



A New Hydraulic Cement. — Many excellent hydraulic ce- 

 ments are already known. A very simple and effective one has 

 recently been added to the number by M. Lorel. It is merely a 

 basic hydrated oxy-chloride of magnesium, and it is formed by 

 addinsr a more or less concentrated solution of chloride of mag'ne- 

 sium to magnesia. The magnesia may be very conveniently obtained 

 by adding quick-lime to the mother liquor, that is the residue 

 in salt works, which contains chiefly chloride of magnesium ; 

 magnesia will precipitate, and is to be calcined. Double chloride of 

 calcium, and magnesium will remain in the liquid ; and if chalk or 

 lime are added, an excellent material for hardening common plaster 

 on walls, etc., will be obtained ; or the liquid itself may be used for 

 moistening the materials in making the cement. Magnesiam 

 cement is extremely plastic, and forms a substance like marble. 

 It takes colour well, and it has such agglutinative power, that one 

 part of it is capable of uniting twenty parts sand. It is, therefore, 

 expected to constitute a means of rendering building easy, where 

 building materials do not exist. 



ISTew Tubulated Syphon. — The common syphon, though made 

 of glass, cannot it is obvious, be used with corrosive fluids without 

 great inconvenience. A partial remedy, which consists of an acces- 

 sory tube containing a bulb, has been long employed. The air is 

 drawn by means of this tube from the lower end of the longer leg 

 of the syphon : the necessary vacuum being thus made, the liquid 

 ascends, and soon begins to flow. The bulb in the accessory tube 

 with moderate care, almost prevents the danger of any of the liquid 

 being drawn into the mouth. M. Zaliwski-Mikorski has, however, 

 invented a syphon which is perfectly safe, and very simple ; and in 

 which blowing is substituted for suction. In his instrument, the 

 accessory tube is attached to the lower extremity of the shorter leg 

 of the syphon, and, on blowing into it, the liquid will be drawn up, 

 and the syphon filled, provided the place of attachment is not too 

 far from the liquid. 



Printing on Glass. — Very cheap and beautiful products are 

 now obtained by printing on glass ; a large amount of the fine 

 effect of stained glass being had for a very small portion of its cost. 

 The inventor, M. De Mothay, uses for colouring matter pigments 

 mixed with a solution of silicate, or silico-borate of potash and lead, 



