374 



Note. In narrow trenches, as for drains, &c., deduct one-third. 

 Digging soft ground for agricultural purposes, from 8 to 10 inches 

 deep, 220 sup. yds. One ton of Sand, river, 20 cubic ft. ; sand, 

 pit, 21 cubic ft. ; gravel, coarse, 19 cubic ft. ; clay, stiff, 19 cubic 

 ft. ; coal, 45 cubic ft. ; earth mould, 32 cubic ft. Spans' Engineers' 

 Tables. 



ESTIMATED PERCENTAGE OF ELEMENTARY SUBSTANCES IN THE 

 EARTH'S CRUST. 



1. Silica ... ... 53*0 7. Carbonic anhydride ] 



2. Alumina ...... 19-0 8. Iron oxides ... I 



3. Lime ...... 6-3 9. Sulphuric anhydride (' 5 



4. Magnesia ... ... 5'8 10. Chlorides ... ... J 



5. Soda ...... 2-5 ii. Other bodies ... 3-5 



6. Potash ...... 2-4 McConnell's Note Book. 



FLY PAPERS. Of the sticky papers, the best are coated with 

 artificial bird lime, prepared by boiling any vegetable oil with a 

 little resin. Rapeseed oil, linseed oil, or any of the cheap oils 

 answer well. After the resin and oil have been compounded, they 

 may be made into a sort of emulsion with a little honey or molasses. 

 The following formula gives good results : resin, i Ib. ; raw linseed 

 oil, i Ib. ; molasses, 4 oz. Melt the resin, add the oil little by little, 

 and while still warm beat up with the molasses. The poisonous 

 fly papers are not open to the objection of being sticky, and if well 

 dried will keep indefinitely. Cooley gives the following formula : 

 Treacle (molasses), honey, or moist sugar, mixed with about i-i2th 

 of their weight of orpiment (yellow tersulphicle of arsenic). Paper 

 to be soaked in the mixture, dried and cut into suitable pieces, 

 which are to be laid on a plate containing a little water. The 

 water dissolves the mixture, bringing it back to the former condi- 

 tion of a syrup, which the flies drink with great eagerness. For- 

 tunately there are other substances which have a very disagreeable 

 taste to human beings, and are not poisonous to them, and yet are 

 quite attractive and fatally poisonous to flies. Redwood's formula 

 for such a liquid is : Small quassia chips, j oz. ; water, i pint ; boil 

 10 minutes, strain, and add 4 oz. of molasses. Flies will drink this 

 with avidity, and are soon destroyed by it. It may also be em- 

 ploved to saturate paper, which maybe used as previously directed. 

 Secrets." 



K CKKAM. (i) Soft water, i gall. ; soap, 4 oz. ; bees- 

 wax in shavings, i Ib. ; boil together and add 2 ox. of pearl-ash. 

 To be diluted with water, laid on with a paint brush and polished 

 off with a hard brush or cloth. (2) Wax, 3 <>/. ; pearl-ash, 2 ox. ; 

 warm water, 6 ox. ; heat them together and add 4 oz. of boiled oil 

 and 5 oz. of spirits of turpentine. (3) The name is sometimes given 

 to a mixture of i ox. of white or yellow wax, with 4 oz. of oil of 

 turpentine. Trade " Secrets" 



