Table 202 continued.

Mr. Mallet found that the shock produced by the explosion of gunpowder, travelled at the rate per second of 951 feet in wet sand; 1283 feet in friable granite; and 1640 feet in solid granite.

The shock of an earthquake travels with a velocity of from 1000 to 1600 feet per second, on an average; but in some cases the velocity has been as high as 2860 feet per second.

A velocity of 1 mile per hour=146 feet per second, or 88 feet per minute, or 5280 feet per hour.

A velocity of 1 foot per second=60 feet per minute, or 3600 feet per hour, or 6818 miles per hour.

The selling price of goods to leave a given per-centage of profit on the whole returns may be found by the following rule:-Multiply the cost price by 100, and divide the product by 100, minus the required profit.

The interest for any number of days due on any principal, may be found approximately by the following rule:-Multiply the principal by the number of days to run, and divide the product by one of the following constant numbers, according to the rate of interest required, viz.:By 121 for 3%; 91 for 4 %; 73 for 5 %; 60'5 for 6%; 53 for 7%; 48.5 for 7%; 45 for 8; 40 for 9%; 36 for 10 %; 29 for 12%; 24 for 15%; 20 for 18%; & for 20%; and finally divide the quotient by 100.

Table 204.-PROPERTIES OF AIR, FROM OBSERVATIONS AT GREENWICH OBSERVATORY.-BAROMETER 30 INCHES AT 60° FAHRENHEIT.

Table 206.-MEAN ANNUAL RAINFALL IN INCHES AT VARIOUS PLACES.

An inch of rainfall on a square yard of surface represents a fall of 46'74 lbs., or 4'67 gallons: on an acre it represents a fall of 22,622 gallons, equal to about one hundred tons per inch in depth per acre.

Inches of rainfall × 14'501 = millions of gallons per square mile: ditto x 2,323,200 = cubic feet per square mile: ditto × 3630 = cubic feet per acre.

LEGAL MEMORANDA; AND PATENTS FOR INVENTIONS.

Bills of Exchange. It is not legal to issue a bill of less value than twenty shillings.

A person under age

is not liable on a bill, but it is valid against all other competent parties thereto.

A creditor having taken a bill in payment of a debt, is debarred from suing for the debt during the currency of the bill, but if the bill is dishonoured he can then sue for the original debt.

When a bill is taken in full satisfaction and full discharge of a debt, the debt is extinguished, and the creditor's remedy is on the bill alone, except where a bill is taken as collateral security.

A bill may be void if the consideration given is illegal; want of sufficient consideration may be insisted on in defence to an action on a bill. A forged bill cannot be sued upon even by an innocent holder for value. An innocent holder for value can recover on a bill although it was given without consideration. The drawer or the acceptor of an accommodation bill, may recover against the party accommodated. The holder for value of an accommodation bill may recover. Payment of a lost bill can be enforced, but the plaintiff must give indemnity against other claims arising on the bill; the holder of a bill that has been lost, or fraudulently obtained must, if he sue for payment, prove he obtained it upon good consideration. When a bill is lost, notice thereof should immediately be sent to all parties concerned.

Date of a bill.-When the date of a bill has been omitted, it will be intended to bear date on the day when it was made, but if the date be omitted for the purpose of the holder supplying the date at his convenience, the bill will be void. If a bill after it has been drawn, accepted, or indorsed be altered in any material respect, without the consent of the parties bound therein, it will discharge them from all liability. An innocent holder for value cannot recover, when the date of a bill has been altered after acceptance, whereby the payment would be accelerated.

Payment of a bill may be refused, unless the holder produce and deliver up the bill.

When a sum of money is paid into a bank for the stated and specific purpose of meeting a bill, the banker cannot place that money to the credit of the customer's overdraft.

The holder of a dishonoured bill may sue the acceptor, drawer and all the endorsers at the same time, but although he may obtain judgment in all the actions, he can only recover one satisfaction for the value of the bill, but he may sue out executions against all the rest for the cost of their separate actions.

Cheques. When a banker pays a forged cheque, he cannot charge his customer with the loss, and when he pays a cheque which has been improperly altered in the amount he has no claim against the customer who

drew it, except for the original sum, unless the careless way the cheque was drawn enabled the fraud to be effected. A cheque should be presented not later than the day after its receipt, after which time the holder keeps it at his own risk against the insolvency of the banker.

An I. O. U. is merely an acknowledgment of a debt, it is not negotiable and does not require a stamp.

Goods Sold. When goods have been sold on credit, and their purchaser becomes insolvent before the delivery of the goods, the seller may countermand the delivery of them, while in transit before they are actually delivered to the purchaser, so long as they are in the possession of the carrier: but the seller cannot retake the goods for non-payment after they are in the purchaser's possession.

Goods Sold on Sale or Return must be returned in a reasonable time, otherwise the sale will stand as an absolute sale, and the price of the goods may be recovered in an action for goods sold and delivered.

A Guarantee must be in writing. The guarantee to or for a firm will cease upon a change of the members of a firm, unless it be expressly stipulated to the contrary.

Patents. Before applying for a patent, it is advisable to search the records of the patent office to ascertain whether a patent has been previously granted for the same invention, or anything approaching it; for this purpose, and in order to protect the inventor's own interest, as well as to insure the preparation of a sound specification clearly embracing all the points of the invention without infringing the rights of others, it is desirable to employ professional aid.

An application for a patent must be made in the prescribed form, signed by the appplicant, and must be limited to one invention.

The application may be made by the actual inventor or inventors, either alone or in conjunction with others, but the declaration must state which of the applicants is the inventor.

If an inventor dies without applying for a patent, a patent may be granted for his invention to his legal representative, if application be made within six months of the inventor's death.

If an applicant for a patent dies, the patent may be granted to his legal representative, and be sealed any time within twelve months after the death of the applicant.

In applying for a patent, the inventor must lodge at the patent office a combined declaration and petition, and a provisional specification, describing the nature of the invention, accompanied by drawings, if required, or a complete specification may be lodged in place of the provisional specification, particularly describing the nature of the invention, and in what manner it is to be performed, and accompanied by drawings, if required.

A specification, whether provisional or complete, must commence with the title, and a complete specification must end with a distinct statement of the invention claimed.