SCIENCE SIFTINGS

New Zealand Tablet, 17 July 1919, Page 46

SCIENCE SIFTINGS

Over Four Hundred Perfumes.

It is interesting to note that 4200 species of plants are gathered and used for commercial purposes in Europe. ■ Of these, 420 have a perfume that is pleasing, and enter largely into the manufacture ". of scents, soaps, and sachets. There are more species of white flowers gathered than of any other c010r—1,124. Of these, 187 have an agreeable scent. Next in order come yellow blossoms, with 951, 77 of them being perfumed. Red flowers number 823, of which 84 are scented. The blue flowers are of 594 varieties, 34 of which are perfumed; and the violet blossoms number 308, 13 of which are pleasantly odoriferous.

World's Greatest Cantilever.

The story of the Quebec bridge, carrying the transcontinental line of the Canadian Government railways oyer the St. Lawrence River, is a record of a great engineering triumph. The bridge is notable as having the longest and by far the heaviest single span yet built, and for the novel method adopted to place the centre span in position. The story of the bridge is briefly told in the Engineering News Record, which says:—"ln the engineering world the name of Quebec has for half a generation been associated with a great prospective engineering triumph. Twice the hopes of success have been dashed, but never in the heart of the true engineer was there doubt that the enterprise would be brought to a successful completion. "Now the great hopes are realised, and the greatest of cantilevers stands closed across the St.Lawrence. Just 10 years ago the south half of the first bridge crumpled under its own weight, dragging 100 men to their death. The investigations and discussions that followed destroyed that first project to its very roots. " But new leaders were found, new ideas developed. On the wreckage of the old there arose the finest creation of bridge-building that any generation has seen. What courage was required to attack the work anew can be realised only when one recalls the extent of the defects revealed in the old design. True, these discoveries were warnings for the succeeding designers, but impressed with the terrible nature of the first experience, their work could not but be haunted by visions of what had happened in that dark August of 1907. Despite the most careful study and precautions, a second accident marred the record of the structure, when the suspended span, while being hoisted into position, fell into the river. The wires had not finished sending the story of this accident to the world when the announcement was made that it would be rebuilt and erected by the same method. This promise was fulfilled, and this greatest of bridges has been erected on the failure of 1907 and the loss of 1916. The Quebec Bridge, it may be pointed out, with its span of 1800 ft., exceeds the span of the famous Forth Bridge by 100 ft., and that these two are in a class by themselvesthe next longest, the Blackwell's Island bridge (New York) being less than two-thirds the span of the Quebec Bridge.