266 
Notices of Books. 
[April, 
therefore, for the transit of the reported rich ores and produce of 
Yunnan and Tonquin, seems certain, and on the removal of 
three obstacles alone a large and profitable trade may be said to 
depend, viz., the consent of the Governments of Tonquin and 
China to open the mines, and the clearance of the frontier of 
refugee Chinese and leviers of black-mail. All these accom- 
plished, the rest is easy. If the Song-koi, or Red River, opens 
a route to Yunnan and Kwangsi, that via the Shan States and 
Bhamo is not the less available, and the two offer equal advan- 
tages, nor is there any reason why their interests should clash ; 
on the contrary, for these points of exit are distant, and one 
gives geographical facilities which the other does not.” 
Sir B. Robertson found it difficult to obtain information re- 
garding the commercial products of Tonquin ; but he met with « 
a native, called Patrus Trueong Vinkky, who was an employe of 
the French Government at Saigon, and had been sent to enquire 
into the trading resources of the country. He represented Ton- 
quin to be rich in products of all kinds, having coal, copper, and 
tin mines, as well as gold and silver. Its agricultural capabili- 
ties are immense, and silk is abundant and cheap, — in faCt, not 
much more than one-third of the price it is in China : it appears, 
however, at present to be much coarser in thread than the 
Chinese, and very badly reeled, and the fabrics made from it are 
of very poor quality. From all he could learn, Sir B. Robertson 
concluded that Tonquin was a very rich country, and, with the 
establishment of good relations with the Government, might be 
made a very profitable one to western nations. 
The Theory of Sound in its Relation to Music. By Professor 
Pietro Blaserna, of the Royal University of Rome. 
London : Henry S. King and Co. 
This volume of the International Scientific Series will be ac- 
ceptable to all musicians who wish to know something of the 
manner in which sounds are produced, and the laws regulating 
them. The author has combined his information in the most 
happy manner, and produced a work useful both to the students 
of physical and musical science. 
The earlier chapters treat on vibrations, and the various well- 
known experiments for their demonstration. After discussing 
the production of sound by means of the vibration of solid 
bodies, the subject of sounding-pipes is explained, and their ap- 
pLcation in the construction of wind instruments. The descrip- 
tion of the manner in which a single elongated tube is able to 
produce several notes, by overblowing, aided by opening com- 
munications with the external air by means of keys, as in the 
flute and clarionet, is correct ; but the singular error has arisen 
